How close is too close?

I know it’s never a good idea to run the input wire of an amp near the tube filament wires, but I wonder how close it can be with no deleterious effects? That’s assuming the filament wires (6.3 VAC) are twisted properly and running at right angles to the input wire.

Hmmmmmmmmmm, good question....

(Sorry! Couldn't resist.)

All together now!  Hmmmmmmmmmm!!

The wires are gonna be pretty close no matter what you do in the stock chassis. We just do what we can to minimize any noise potential.

That said, I've got some long leads in my custom case with no deleterious effects.

(just knew I'd get to use that word today)  



PS - the only hum issues here were due to a loose mount on the can cap. Seems to be a common problem easily fixed.

I’m not referring to any specific chassis, but just wondering if say, you have an input wire 2” away and at right angles to the filament wires.

Try this thread at DIY audio.  
http://www.diyaudio.com/forums/tubes-valves/211731-heater-wiring-bad-ugly.html

I think as long as your aren't twisting the input wire together with the filament wires you'll be ok.

Read and saw some interesting restaurations from blueglow where subtle repositioning of some of the wiring evened out distortion on both channels - with the wiring moved around slightly it went from 1.5 to .5% hm I think the one I am thinking of was actually the restauration or rebuild of a pair of MK III's