shielded wire gauge minimum for typical marshall preamp

[pjd3]

Hello,

I'm getting an order together for some parts and components for a JCM800 2204 build and am ruminating over the minimum required gauge for preamp wiring, which will include shielded coax for "Input to V1, A HV FET input boost board, Zero loss series effects loop", and perhaps a few more gain mods with entail panel switches and even relay boards.

At work I have access to shielded coax cable that is 26AWG. In the process of building amps its normally 22AWG for most everything excluding heaters and some power supply things, so, ever though I see that there isn't ever much more than a handful of milli-amps running about a preamp for signals, I'm feeling a bit tentative about using the 26AWG for these preamp hookup duties, only because 22awg is the commonly seem gauge. I'm confident that 26awg has plenty of current capability for typical preamp signal paths but, would just like to check in with a few of you to make sure I'm not over-looking anything that's not obvious to me.

I also see that Amplified Parts carries a very similar shielded cable that is also 26AWG.

Thank you!
Best,
Phil

[xtian]

26ga is no problem for preamp signal wiring. More important is the outside diameter of the coax--I prefer slender vs chonk.

[ViperDoc]

Mogami makes some really nice 26 guage coax. I only notice a need to carefully tin the center conductor and to secure the cables after soldering to prevent deformation and breakage. It's much more flexible than the Belden wire I used previously.

[pjd3]

Thanks guys, that's good to know, I figured as long as the jacket is able to insulate the surrounding voltage it would be oK,

Its good to know I can move on with the build with less fear! And yes, I did hear good things about the Mogami and was tempted to "just order it". But, I'll give the 26awg stuff in work a try. I will be vigilant about giving good support to the cable end connections.

Best,
Phil Donovan

[pjd3]

Just to note, the cable from work is definitely more slender than "chonk".

Phil D.

[martin manning]

Does this coax cable from work have a number like RG-XXX?

[bmx]

26 awg should be good. Pickup wiring typically is 28 awg and we know that stuff gets bent all around by the average person with a soldering iron.

[pjd3]

I'll check the type name on the coax tomorrow. It is actually 25awg which is strange, never saw that gauge before.

It has both stranded shielding outside of a foil shield, and the inner conductor is solid which I didn't expect. I made the wrong assumption that it would be stranded.

Best,

Phil D.

[Stevem]

I use Belden 8425 .

[pjd3]

Written on the cable itself is:

Belden 7805 RF100A 6Ghz wireless 50 ohm coax - and it is 25AWG solid core.

So, this cable is obviously designed to handle some high frequency transmission of signal. I don't see any reason why it also wouldn't be fine for the preamp signal mods and routing on my current 50 watt JCM800 2204 build.

Thanks,
Best,
Phil D.

[martin manning]

So RG-174 spec. The only down-side there is that the insulation is PE. I'm a fan of RG-179, which has PTFE insulation. It's 28-30 AWG, and I don't have any problem with that.

[Encom]

On my next amp I want to try RG188. I believe its center wire gauge is 24awg.

[TUBEDUDE]

26ga is no problem for preamp signal wiring. More important is the outside diameter of the coax--I prefer slender vs chonk.

Don't we all!
For coax, the smaller the better, if flexible. A gauge difference might change capacitance, but at these short lengths that won't matter.
I prefer the Mogami 2314.