Heater wiring question

[jamme61]

about to build a mojotone brown face deluxe kit. My question is I usually twist the heater wires but I have a Morgan AC20 amp and noticed he doesn't twist the heater wires? I was thinking of giving this a try but like opinions on noise issues without twisting the wires? thanks for any input.

[pompeiisneaks]

about to build a mojotone brown face deluxe kit. My question is I usually twist the heater wires but I have a Morgan AC20 amp and noticed he doesn't twist the heater wires? I was thinking of giving this a try but like opinions on noise issues without twisting the wires? thanks for any input.

I've done a build with straight wires w/o any hum issues. Mostly just make sure they are away from signal wires, and enter and exit clearly away from the tubes. I saw another amp maker, maybe reeves? That had straight heater wires w/ no noise.

It's not super hard to twist them, but it also seems to me to be not so super important.

If it's easy enough for you to redo them, because you get hum, then give it a try.

~Phil

[sluckey]

I've successfully done it both ways.

[jamme61]

thanks guys - im going to try it untwisted, if I get hum, i'll do it again. thanks for the input - waiting on the kit to arrive.

Thanks for the pictures- it will help me out a lot. Great looking builds.

[jamme61]

was looking again at the ac20 and he is running pin to pin with the heater wires - here's a link to the pics on gear page let me know what you think - it looks like less wire used-

https://www.thegearpage.net/board/index ... y.1970212/

[pompeiisneaks]

I mean if you're trying to save 3-5 cents then yes, but the way sluckey dips the wires away from the tubes directly away from the tube socket means the heaters have very little close contact to any signal carrying wires, avoiding hum injection. I did a very similar thing. read merlin's heaters chapter, it covers the best way to make sure the heaters come in and right back out as directly as possible.

Not saying you'd have a 'ton' of hum with them like this, but it's going to have a way higher chance than the way sluckey's amps do it.

~Phil

[martin manning]

The photo above is essentially the same as Soldano parallel bus wires.

[xtian]

Years back, I left an extra long heater wire to V1, so during operation I could move the wire around. I could not intentionally inject hum into the circuit, even placing the heater wire parallel to the input grid wire. Maybe on a high gain amp this would be possible? Anyway, that was the moment that taught me that the amp's grounding scheme is far more important than heater wiring in keeping hum to a minimum.

[Bergheim]

Years back, I left an extra long heater wire to V1, so during operation I could move the wire around. I could not intentionally inject hum into the circuit, even placing the heater wire parallel to the input grid wire. Maybe on a high gain amp this would be possible? Anyway, that was the moment that taught me that the amp's grounding scheme is far more important than heater wiring in keeping hum to a minimum.

+1
Pretty much experienced the same thing. I exlusively use zip wire from scrapped power adapters these days. It doesn't have the classy look like twisted wires but it does the job just fine and is so much easier to work with. And it doesn't rob quite as much real estate as twisted wires either, which is a plus in (real) ptp builds.

[Phil_S]

The heat wire lead dress question is ages old. The conventional wisdom seems to be that high gain amps need special attention to keep heaters away from signal. Other than that, it usually isn't a problem, though anything can happen. I've observed there ares:
1) Heater wires tucked into the chassis fold. It's very tidy. I find this hard to do well.
2) Heater wires in the air twisted, signal wires on the chassis. Reasonable tidy, probably easier to implement, particularly for less experienced builders.I started out this way and I stick with it.
3) Do it with zip wire (lamp cord) because the wires are held parallel.
4) The way you show it above, lining up the pins on the tube sockets for a straight run.
5) Lazy loops. Look at some of the Express pictures here at TAG.
They all work most of the time. I suggest it isn't necessary to obsess about it, not that you are doing that.