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Digital audio playlist

01 Introduction - what is digital audio?

02 Binary and digital data

03 Data size, data capacity and data rate

04 The six physical forms of digital data

05 What is an analogue to digital audio converter?

06 Analogue to digital audio conversion - The 2 primary parameters

07 Analogue to digital audio conversion - Sample rate

08 Analogue to digital audio conversion - Nyquist theory

09 Analogue to digital audio conversion - Aliasing

10 Analogue to digital audio conversion - Word length and quantisation

11 Analogue to digital audio conversion - Common word lengths

12 Analogue to digital audio conversion - Setting record levels

13 Down sampling and dither

14 Uncompressed digital audio file formats

15 Compressed digital audio file formats

16 Digital audio interconnection signal types

17 Digital audio synchronisation

18 Connecting audio devices with Toslink leads

19 Connecting audio devices with AES3 or SPDIF coaxial leads

20 Latency

Digital audio 17
Digital audio synchronisation 

Level of challenge Hard

 

Welcome to this tutorial on digital audio synchronisation.

 

Digital audio synchronisation is essential when audio devices are connected digitally. Unlike analogue audio connections, when digital audio signals travel between devices (such as a DAW and and external hardware effect processor) they must be synchronised by a common clock. Like cogs in a mechanical system, they must mesh.

 

Devices that we regularly need to connect include ..

In this context we are not talking about audio signals travelling down computer connectors such as USB, FireWire, or ethernet leads. Signals in those situations can usually be considered to be synchronised within an integrated computer environment.

 

Caption - Digital audio signals

Digital audio signals consist of long sequences of individually discreet measurements of amplitude (called samples) taken at very precise intervals. They are like super precise join-the-dot pictures. The number of samples per second is expressed as the signals sample rate or frequency. For example, there are 48,000 samples of amplitude every second in a 48KHz digital audio signal.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Digital clock

Digital audio devices require a super accurate clock to ensure the precise timing of samples. If they are operating alone, they use their internal clock. But in a network of connected devices, timing errors can occur, which at best cause subtle audible distortion, and at worst produce audible clicks and pops and even complete drop-outs.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Digital clock master

It is therefore essential that individual devices in a digital audio network, conform to a common timing clock, known as the clock master. The clock master is set to a sample rate which all connected devices must follow.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Word clock

Work clock is a timing signal passed between devices on a digital audio network. One device is set as the clock master and it's job is to generate and send a word clock signal to the other devices on the network, each of which are set to slave to it. This ensures that the timing of all devices is synchronised. Word clock is embedded in almost all digital signals or can be sent as a separate signal commonly referred to by the connector it uses, BNC. The word clock signal embedded in an AES3 signal is also known as AES11.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Timing errors

When an analogue signal is converted into a digital signal by an analogue to digital converter synchronised by its own internal clock, the samples occur at very precise intervals. Almost all modern converters (last 10 years) are super accurate. However, once converted there are 3 primary conditions that can produce timing errors.

 

They are ..

  1. Jitter
  2. Drift
  3. Lack of sync

Caption - 1. Jitter

Jitter is sample timing irregularities in an individual digital signal and is most commonly caused by the interference issues and electrical properties of AES, SPDIF and BNC leads as a digital signal travels between devices. The longer the lead is, the worst the jitter can become. Jitter is a problem for larger networks carrying signals long distances, but not usually a big problem in smaller project and home studios.

 

Jitter can also be produced by a digital device, such as a converter or effect processor, but new super accurate chips commonly used in modern audio devices have minimised it.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - 2. Drift

Drift is caused by serious transmission problems in a lead or by the clocks of two devices in a network operating out of sync with each other. This can happen if the devices are not adequately synchronised, or one clock is operating less precisely than the other.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - 3. Lack of sync

In this situation, devices in a network are operating independently according to their own internal clocks and are not synchronised. Clicks, pops and drop-outs in the audio signals exchanged between them are inevitable. The same symptoms occur when the sample rates of connected devices differ.

 

Caption - A typical network

First, let's consider a simple system in which an audio interface is connected to a DAW with a fast USB connection. The audio interface has both analogue to digital and digital to analogue converters. Incoming analogue signals are digitised and passed into the DAW where they are recorded, edited and processed. Signals which have already been recorded, and those produced by plug-ins, are sent back to the interface, usually in the form of a stereo master monitor mix where they are converted back to analogue to be sent to the monitors.

 

The DAW and the interface are closely integrated and can be considered as one system. Although the DAW is in effect a slave device, and the interface is set as the clock master, with its clock regulating all the analogue to digital, DAW processing and digital to analogue conversion, there are no synchronisation issues to resolve. Everything works well.

 

Demonstration But what if we add a new external hardware effect processor to this simple system and decide to hook it up digitally. We connect the digital out of the interface to the processor and the digital out of the processor back to the interface. Typically this would use a Toslink, SPDIF or AES3 connection. Now there are 2 types of signal that must be exchanged between the devices, the audio signal and a clock synchronisation signal.

 

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Clock masters and slaves

Demonstration In this situation it would be sensible to leave the audio interface as the clock master and to set the processor as a clock slave, synchronising to the clock master. To achieve this you must make 3 settings on the effect processor ..

  1. Ensure it's sample rate is set to the same sample rate as the interface
  2. Set it to clock slave, or digital clock mode
  3. Select an incoming clock signal - BNC or embedded

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Embedded and BNC word clock signals

Work clock is a timing signal passed between devices on a digital audio network. It is a square wave at the same frequency as the sample rate.

 

Word clock signals can be transmitted in 2 ways ..

  1. Via a separate word clock connection using a word clock lead which terminates with BNC connectors.
  2. Embedded in an SPDIF, AES, Toslink or ADAT signal - in this case the word clock, or 'bit clock' as it is known, runs in parallel to, and at the sample rate, of the audio signal.

Demonstration continued Because there is no advantage in using a BNC word clock connection, and our effect processor and audio interface may not have them, we can safely choose the embedded work clock option.

 

Caption - Why use a BNC word clock connection?

Contrary to popular belief, distributing work clock signals separately via separate BNC connectors does not produce superior synchronisation. Fortunately, project and home studio owners rarely need to use them. Also, many cost effective devices don't have BNC connectors.

 

However, when you have a one way digital connection from a source device, such as a mic pre-amp channel with its own built-in analogue to digital converter, to an audio interface, and the interface is the clock master, the mic pre-amp has no way to synchronise to the system. There are 2 solutions ..

  1. Set the pre-amp channel as the clock master
  2. If your interface and pre-amp channel have BNC connectors, send word clock from the interface to the pre-amp channel

Caption - Daisy chained BNC word clock connections and termination

BNC connected devices can be daisy chained, but the last device in the chain may need to be terminated to prevent the word clock signal 'reflecting' back down the lead. This is usually accomplished either with ..

There is a relationship between cable length and signal strength that determines whether a signal should be terminated. A device's manual should idicate which, if any, type of termination is required, but if it doesn't, it should be possible to try different options and see which allow the device to lock without audible problems.

 

Caption - Correcting jitter and drift

At this point we should pause and consider the problem of lead induced jitter. If we are passing a clock signal down a lead, will it not be vulnerable to jitter also? The answer is yes! A master clock device cannot stop jitter developing in a lead, or other device, as it travels round a network. So we now have the problem of both the audio signal and word clock signal being affected by jitter!

 

We are now in danger of straying too deeply into digital theory, so it may be helpful for us to think of this problem like this ..

Because jitter and drift only becomes an audible problem when digital signals are converted back to analogue, it makes sense that the final correcting of these problems is handled by the master clock device, and that this device is itself the point at which signals enter and exit the central recording and mixing device, ie the DAW. It is therefore understandable that many believe that not only should your audio interface contain excellent converters and an accurate clock, but also jitter and drift elimination circuitry, a process sometimes known as "clock recovery".

 

Caption - To sum up

Welcome to this tutorial on the differences between microphone pre-amplifiers.



Microphone pre-amplifiers play an important part in the recording process and can make a useful contribution to the character of the sound. In this video we will examine the primary design factors that differentiate them, and how these factors affect their uses and audible character.



A microphone pre-amplifier performs a simple but essential job. It must amplify the very quiet mic level signal coming from a microphone to line level so that it can be processed, recorded and sent to a PA or monitoring system. It must do this without distorting or introducing unwanted artefacts into the signal. 







Caption - Ergonomics

The first thing we need to look at when choosing a mic pre are it's features. Some mic pre's are minimalist, whilst others are designed to accommodate a wide variety of microphone types and recording set-ups. Here are the primary things to look out for ..

Balanced XLR mic input

Balanced XLR line output

Hi-Z DI instrument input for connecting an electric guitar or bass guitar

Send return insert connections - to allow the connection of a compressor or EQ

Gain control - to control the input gain

Input gain metering - some mic pre's only have a single LED which changes colour according to the signal level, whilst others will have segmented peak metering or a VU meter.

Output level control - to attenuate the output level. This is useful if you are driving the input hard in order to add harmonic colouration and need to reduce the output level

Trim control - which may allow fine tuning of either the input gain or output level

Phantom power

A pad switch to reduce the input circuitry sensitivity and prevent input overloads

Polarity reverse - useful for multi-mic'ing situations

Impedance control - to accommodate the needs of different microphone types, especially ribbon mics. Condenser and dynamic mics operate well with an impedance input of between 500 and 8000 Ohms, 2000 Ohms being typical. Changing the impedance can have a subtle effect on the frequency response. Ribbon mics will need something like 20 k Ohms.

A dedicated ribbon microphone mode - which will raise the input impedance and disable accidental enabling of phantom power

High pass filter - to roll off unwanted low frequencies

Form factor - do we need the device to be portable, stand alone, rack mountable, or integrated into another device, such as an audio interface?



Caption - Technical specifications 

The technical specifications of a mic-pre amp will give you some indication of the quality of its design and manufacture. The primary things to look out for are ..

Frequency response - unless we have a specific need, we will want this to be as wide and flat as possible. This means at least 20Hz to 20kHz with no significant changes at any frequencies. We may not always want a flat response, and prefer a response that boosts some frequencies perhaps in order to add clarity or definition, but either way we can check the frequency graph if one is available.







Noise performance - mic pre spec's contain various confusing statistics on noise and distortion. Most devices perform extremely well or adequately, however, if we plan to record very quiet and delicate sources we will want to test performance audibly.



Dynamic range - An input gain range of between 0 and 60dB is typical and should accommodate most situations, especially if a trim control offers another 10dB or so of additional gain.




Caption - Transparency vs character

In the early years of microphone pre-amp design, the limitations of available electronics made it difficult to process a signal without distorting it in some way. As designs improved, these distortions became more acceptable, even desirable sometimes, adding harmonic colour and enhancing the signal. Today we refer to such designs as vintage or classic and the sound they produce as being silky and smooth or having character or warmth.









Modern electronic components have advanced to a point where transparent cost effective designs are common place, distortions are to all intents and purposes inaudible, and the full character of a microphone is revealed. In fact, the differences are so small its hard for even experienced engineers to identify devices in blind tests.



It is worth saying that even differences between transparent and character designs can be hard for the untrained ear to detect, and that choice of mic pre-amp usually has less of an impact on a recording than the choice of mic and its positioning.



However, many characterful designs are still manufactured and we therefore have a great deal of choice.



Caption - Character 

There are many components that contribute to giving a mic-pre its unique signature sound, but perhaps the 2 biggest are ..

the use of valves or tubes in the circuitry

and, transformers on the signal input and output stages



There are 2 primary ways in which components such as these can effect the signal.



Caption - 1. Slew rate

Firstly, slew rate. The slew rate is a measure of how fast an amplifier can respond to sudden changes in amplitude, especially those that occur at the transient, or attack of a sound. 







Early designs had slower slew rates which tended to soften or smear transients. This has the effect of making the signal sound more organic and less detailed, and can be useful in minimising the sounds of clicks and pops from instruments and saliva.







Caption - 2. Harmonic colouration

Secondly, harmonic distortion or colouration. Harmonic distortion was originally an unwanted side effect of early electronics but is now recognised as a useful effect. Even integer multiple harmonics tend to thicken the sound, whilst odd integer multiple harmonics can add some brightness. These effects can be subtle, and difficult to achieve with other processors such as EQ or exciters.



Caption - Comparing three mic pre-amps

Demonstration - Sound Skulptor M573, Grace Design m501, and Dave Hill Designs Europa.

For this demonstration we are going to look at three devices ..

The Sound Skulptor MP573 is a re-creation of the classic 1970 Rupert Neve design for the Neve 1073 studio console. This device utilises Carnhill transformers on the input and output signal path, and these, together with a slow slew rate, deliver a smooth sound in which transient are smeared and harmonic colour is added.

The Grace Design m501 - a modern transparent transformer-less design

And finally, the Dave Hill Designs Europa - a unique design than utilises digital control to allow the slew rate and amount of additional harmonic content to be determined by the user.

 

Caption - Don't forget to subscribe

The script for this tutorial, with accompanying screenshots, can be found at projectstudiohandbook.com 

 

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Thanks for watching.

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