Audio interconnection 20
Making audio leads and soldering

Level of challenge Intermediate

Welcome to this tutorial on making leads and soldering.



Many project and home studio owners connect their devices with off-the-shelf leads. Providing the correct leads are being used, this is perfectly acceptable. So why would you want to make your own leads?

 

The primary reasons for making your own leads are ..

  1. cost - if you need a lot of leads, making your own will save a lot of money
  2. it will help you to learn the practice and theory of interconnects
  3. you will be able to tailor leads to your exact requirements, especially length
  4. you can make simple repairs and thus save time and money

Caption - What's involved in making leads?

The processes for making leads are straightforward, but for quick results require a specific order ..

  1. planning - this involves determining how long leads need to be and identifying and buying the necessary connectors and cable
  2. cutting and labelling
  3. stripping the cables
  4. soldering connectors
  5. gathering groups of cables into looms

Caption - What tools do you need?

Demonstration

Here are the basic tools required ..

  • thin nosed pliers
  • wire cutters
  • wire stripper
  • sharp knife
  • insulation tape
  • temperature controlled soldering iron rated between 40 and 50 watts
  • solder iron sponge
  • de-soldering tool
  • common resin or flux cored solder rated for around 300 degrees melting point
  • mini-vice and or helping hands
  • adjustable light source
  • labelling machine

Caption - Planning

When planning your leads, you will need to ask these questions ..

  • how long does the lead need to be? - its a good idea to make your leads longer than you need in order to accommodate any future re-siting of equipment
  • are the leads for permanent installation purposes or will they be subject to regular handling? - this will help determine the gauge of cable you will choose
  • is there a limit to the diameter of the cable the connector can accommodate?
  • what are the connector requirements? - do you need male and female connectors?
  • will it be better to use multi-core cable or individual cables?
  • do you want to use coloured cable to make it easier to identify different types of connections?

Caption - Cutting leads to length

Sometimes its a good idea to cut cables longer than required. The nature of a project studio is that devices are constantly being moved around and updated and you want to make sure that your leads are long enough. You may want to ask the question, where might this device be located in a years time?

 

Caption - Labelling

Once you've cut your leads to length, it's a good idea to label them about 15cm from the ends. You can label the connectors but they will be harder to read once plugged into a device. 15cm will ensure they don't interfere with soldering and repairs. Labelling is essential, especially if you are going to gather them into looms. Some forms of cable, such as multi-core, have labelling numbers printed on the outer insulation.

 

Caption - Stripping cables

Demonstration Stripping cables accurately will make soldering much easier ..

  1. take the cover off the connector, hold the cable against it, and estimate how far back the cable should be stripped
  2. strip the outer insulation
  3. unbraid and twist together the earth shield
  4. look at the distance between the connectors cable grip and the connector poles and strip the inner insulation accordingly
  5. trim the inner cores to length and twist them
  6. tin the cores

Caption - Tining

Demonstration Tining is an essential part of the preparation process. A thin layer of solder is added to the cables and connector contacts, or poles, to aid the smooth flow of solder.

 

Caption - Soldering the connectors

Demonstration Here's a run through of the complete process of soldering ..

  1. turn on your soldering iron and set it to between 300 and 350 degrees. Around 320 degrees should be fine. If your solder melts quickly at a lower temperature then use that. If the solder is taking more than a half a second to melt, increase the temperature.
  2. wet your soldering iron sponge
  3. ensure the soldering iron tip is clean (use the sponge) and tin it
  4. push the tinned cable you have prepared through the connector cover
  5. tin the contact poles, and if available fill connector pole 'buckets' with solder
  6. if possible make a mechanical contact between the cable and contact. You may need to bend the cores with a pair of pliers. Some connectors have holes in the contact you can push the cores through.
  7. hold the cable to the connector, and heat the connector whilst simultaneously allowing some solder to melt and flow over the connection. You should not hold the soldering iron to the connector for more that a couple of seconds. If it takes longer for the solder to melt, your iron needs cleaning or is not at temperature, and you risk melting any insulation materials surrounding the core or which electrically isolate the contact. You want to deliver a high temperature to the joint quickly and for as short a time as possible.
  8. as soon as sufficient solder has flowed, remove the iron and blow gently to cool the joint. You will see the solders surface change from glossy to matt.
  9. inspect the joint visually and stress test it by pulling on it gently
  10. inspect the joint to ensure no short circuits have been made with other contacts or cores
  11. replace the connector covers

Caption - Cable management

You can gather cables into looms by using cable ties or plastic conduit. Cable ties are available in permanent and re-usable releasable format. Once tightened, you can trim the excess from the tie with some wire cutters.

 

You can also fit cable strain guides and cable ties to racks and studio furniture to direct and support cables.

 

Caption - Thanks for watching

The script for this video, with accompanying images, can be found at projectstudiohandbook.com 

 

We suggest you subscribe at our YouTube channel, and join our mailing list at our website to receive notification of new videos, blog posts and subscriber only extras.

 

Thanks for watching.

The copyright in this site's design and content is owned by Matt Ottewill © 2013 to the present day. Unauthorised duplication, redistribution, publishing, copying, hiring, lending, broadcast and public performance of all site content for commercial gain is prohibited. Use for non-profit educational purposes is freely allowed, please reference this site.