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

 

From: motm@yahoogroups.com [mailto:motm@yahoogroups.com] On Behalf Of Ti_
Sent: Wednesday, March 11, 2009 4:56 PM
To: MOTM
Subject: [motm] Suitable Wire Guage Questions

 

So, we know 22 guage is what's used with MOTM modules for non-audio
connections, but is there a minimum or maximum gauge to go by?
I've got a whole mess of 24 guage wire I've scrapped from dead things at
work, would that still be too thin?
Also have a bunch of 18 gauge which I guess could be a be unwieldy, but
would Too big of wire to a reasonable size add any problems?
Last, I've got a big bunch of rg-174.  How long could I possibly run it to
make normalizing cables inside the modular without problems, 2,3,4 feet or
more?
Thanks,
Tim