MOTM

Hi Tim,

I think in most cases for modular synth use, going a gauge or three in either direction isn’t going to be particularly critical since the distances are relatively short. The Oakley MultiMix modules I just built specified using 26 gauge for the PCB to audio jack connections, probably because it used small MTA connectors, and it seems to work well and sound fine.

The main reason not to use too fat of a wire gauge is that it may not fit through the holes in the PCB or switches etc. and things like crimp connectors and MTA connects etc have a narrow range of allowable gauges for them to work correctly. Unless you are getting into lengths (cumulative or one piece) of 10s to 100s of feet, the main concern would be handling and reliability IMHO. Too thin of a wire might be hard to work with, especially with big hands, and it can often be too fragile. Too fat of a wire may be too stiff and hard to place easily and being stiffer, could possibly cause PCB traces to lift or break if the wire is moved.

I personally like to lean towards using the biggest ‘reasonable’ size but . . if you look at the chart bellow and you used a 1 foot piece of 24 gauge instead of a 1 foot piece of 22 gauge, you’d only be adding just over one hundredth of an ohm in resistance! When you consider that a 1% 1k ohm resistor in your circuit can be as much as 10 ohms off in either direction, going a gauge step or two in either direction shouldn’t be a concern.

And the shielded cable shouldn’t be a concern either. Think about how long microphone snakes are for concert mixing consoles (100 to 300 feet long typically) and the signals are often much weaker. 4 or 5 foot pieces inside your modular shouldn’t be an issue. ;-)

From http://www.epanorama.net/documents/wiring/wire_resistance.html

Wire Gauge Resistance per foot

4 .000292

6 .000465

8 .000739

10 .00118

12 .00187

14 .00297

16 .00473

18 .00751

20 .0119

22 .0190

24 .0302

26 .0480

28 .0764

John L Rice