Terminating Litz Cables using a solder bath

Here we have a pair of short, 1 metre, speaker cables featuring Audio Note`s new Isis LX 168 Reference Copper Litz cable terminated with Audio Note Silver Plated 4mm banana plugs. 

On the odd occasion we do get asked to make up special cables for customers, which we are happy to do. Now Audio Note cables are generally litz cables. Whereby every strand is polyurethane coated, the benefits of litz cables is a reduction in the skin effect and proximity effect - great for audio in other words. In order to terminate these cables you need to remove the insulation. Now you can painstakingly do this with a soldering iron or you can do what Audio Note do, use a solder bath. Effectively a device that heats up a small tub of solder, in the form of solder nuggets. Dip the exposed wire ends in flux then dip in the solder bath. The coating burns off and the copper wire is tinned. Then you can use a regular soldering iron and your favourite solder to connect the wires to your plugs.

Solder baths make life so easy, we purchased one especially for the job (I was so impressed I bought the company! - couldn`t resist). We are looking to buy in bulk to make them available to you guys.

So in the meantime if you guys want your Audio Note cables or Cardas cables, another lover of Litz, tinned ready for terminating please let me us know. There will be a small charge.

Happy DIYing

Nick Lucas

We have had some interesting comments from Mr Mars on this topic which I felt we had to add:

I'm pleased to see that you are promoting the use of a solder pot/bath for making up litz connectors. I could not have made up the number of cables I have done recently without one (not without seriously damaging my mental health anyway) ;-)

I found the following formula works for AN 19 strand silver litz using WBT silver solder:

A) First 'dip' 400 degrees C @10 secs

B) Scrape off burnt polyurethane 'scum'

C) Second 'dip' 400 degrees C @6 secs

D) Scape off scum

E) Solder component as needed.

I usually pre dip with additional liquid flux as using flux based solder in a pot means it burns off and the solder does not flow.

For soldering finer silver litz eg SOGON the above formula will result in melting the silver strands so experiment is need to get balance of temperature and time.   It would be good to point out that before using on a particular cable that whoever is doing it must experiment to find optimum temp and time for dipping in the pot. I reckon on Audio Note cable 350 Degrees C is the minimum to burn off the insulation. Silver wire will melt more easily than copper, so time is important. Melting silver litz is guaranteed to make anyone curse.   Also the flux issue is important. I used WBT silver solder when this goes in pot the flux will burn off pretty quick and create a fair bit of pungent smoke......ventilation is important here, also scum will appear on surface of molten solder this must be skimmed off periodically. To keep wire fluxed I got into habit of dipping wire into a liquid flux (Somerset Solders)immediately before tinning in solder pot, this helps solder flow into fine litz.   Thank you for your input.    With regard to the solder, we used a liquid flux, dipping the wire in that bofore dipping in the solder bath. We actually used lead free solder nuggets with 0.3% silver and 0.7% copper. Then we use a standard iron with Audio Note 6% silver solder.