Am I Crazy to Use this Wire for my Heaters?

[Alexo]

I guess it's just standard 18 gauge zip wire. I know everybody does the twisted pair thing, but isn't the purpose of the twisted pair to get maximum emf coupling between the out-of-phase leads so that the radiating 60 hertz signal cancels? Wouldn't paired-up zip cord offer maximum emf coupling since the two cables are basically glued together? Bad idea?

Thanks!

-A

[Mooreamps]

I think you would be fine. 18 guage wire can support plenty of current for heaters, which should be your first concern. EMF cancellation is a second order source for hum injection. But I am of the mind to believe the two fields generated by the two wires side-by-side would cancel each other out.

-g

[particle]

You could always try twisting the zip wire and have the best of both worlds...
(however, your milage may vary depending on the type of zip wire).

[LooseChange]

That wire would be fine. Just be sure to tin each end as you work along the sockets.


The biggest difficulty I run into with heavy gauge wire is trying to hook a few 9 pin preamp tube sockets in a row. The heavy gauge wire makes it really tough to get them through pins 4 and 5 and out to the next. I try to scale the gauge down as I move further away from the power tubes.

[zaphod_phil]

After seeing gut shots of of "first born" Marshall 18Ws, I now use zip wire for all my heater connections. 22guage or 20 guage is usually fine, because the wire lengths are now much shorter due to not being twisted, and therefore ohmic losses and heating effects are also reduced. Hum cancelling is equally effective as with twisted.
See http://www.18watt.com/modules.php?set_a ... _photo.php
http://www.18watt.com/modules.php?set_a ... _photo.php

[brownnote]

I've thought about it, but how much of a time saver is it really?
It takes about 5 seconds to use a drill to twist a length of solid core wire.

From that point you are working with small lengths of wire (same thing as zip cord)
except you don't have to tin the ends, and the solid core fits easily into small 9pin lugs.

If you're not braiding your twisted wire together to make a real pretty heater loom, and you're just daisy chaining it like you would with zip cord, I can't see how it would be any faster or easier to use the zip cord.

[Mooreamps]

maybe zip cord is all he has.

[floridajack]

i have used 20ga zip cord, twisted 20ga and 22ga solid and even some 22ga stranded for heater wires and fond no difference when it comes to noise. just depended on what i had at hand. (twisted looks prettier!!)

even 24ga has the ampacity for heater wire on 18w and 36w amps.

fj

[LooseChange]

I worked on a Boogie head (Dual rectifier 100 watt). All the heater wires for the power tubes were bare wire, preformed and straight runs on each side of the tubes. There you go.

[zaphod_phil]

I've thought about it, but how much of a time saver is it really?

I don't know. I just like zip cord now. And yeah, I guess I'm even too lazy to get the drill set up....

[morcey2]

I've thought about it, but how much of a time saver is it really?

I don't know. I just like zip cord now. And yeah, I guess I'm even too lazy to get the drill set up....

Necessity is the mother of invention, but everyone forgets that laziness is inventions illegitimate father.

[beamer]

Mooreamps, what do you mean by "second order source for hum injection"?
Always looking for tips on reducing hum.
I am using twisted 22 gage on my latest build. 3 amps worth of heaters if I use 6L6's. The 22ga is rated at 7 amps, probably a little less twisted.
Judging from you guys' answers, starting to think maybe we make too big a deal of this twisted heater wire thing.
Maybe, just maybe, this is one of those "everyone says it, doesn't make it true" things?
I'm no expert.
scott

[brownnote]

I've thought about it, but how much of a time saver is it really?

I don't know. I just like zip cord now. And yeah, I guess I'm even too lazy to get the drill set up....

I hear ya

The boogie, soldano, etc "air dialectic" method of heater wiring looks pretty slick, and some say it's easy, but to me it looks like a PITA to get right.

[zaphod_phil]

Judging from you guys' answers, starting to think maybe we make too big a deal of this twisted heater wire thing.

Yeah, the benefits of twisted wire for 60Hz/50Hz heater wires have been somewhat exaggerated IMO. You can safely use thinner wire, if you don't twist it, so that the lengths stay real short.

[floridajack]

now this is just from my "book lernin'" about all things electrical (i'm a mechanical engineer,) but the ampacity of wire seems to be of little concern in the projects we do.

for instance, 24ga solid is rated for 5 amps and drops off to 4 at 120 FEET!!! i don't think there's 100 feet of wire in the whole amp (excluding the xformer windings.)

let's not get too close to the edge, but if you're only drawing 3 amps, then 4 is a 33% safety factor. does that sound right?

fj

[LooseChange]

I've thought about it, but how much of a time saver is it really?

I don't know. I just like zip cord now. And yeah, I guess I'm even too lazy to get the drill set up....

Do you just go from socket to socket keeping the zip cord together between sockets? Got a picture of that, I'd like to see it.

Now, how about if you just lift the heater circuit on DC and run them directly in line from socket pin to socket pin? That's gotta work pretty well.

[zaphod_phil]

Do you just go from socket to socket keeping the zip cord together between sockets? Got a picture of that, I'd like to see it.

I don't have a picture of one of my amps that uses zip cord, and my camera's broken. However, you can get the general idea from these first-born Marshall 18W pictures in the gallery:
http://www.18watt.com/modules.php?set_a ... _photo.php
http://www.18watt.com/modules.php?set_a ... _photo.php
I prefer to use bicolor wire or striped wire, usually sold as cheap speaker wire, so I can keep track of the phase.

Now, how about if you just lift the heater circuit on DC and run them directly in line from socket pin to socket pin? That's gotta work pretty well.

I'm not sure I follow how DC-elevating the heaters makes it different... I normally DC-elevate all my heaters anyway.

[LooseChange]

Thanks for the pictures, that explains it.
Yes, the DC elevated heaters will help to reduce any noise that may be provided by the non twisted approach. I DC elevate all my heaters too.

[Alexo]

Thanks for the advice guys, I wired up the amp with zip cord last night, we'll see how it comes out tonight when I fire her up but I'm betting it'll be OK, noise-wise. Luckily this was an all-octal circuit, or else that 18 gauge wire would have been a huge nuisance.

Gotta say I liked how solid core would stay in place a lot better than this floppy zip stuff, but at least now my friends will stop asking "what's that rope in there for?" when I show them the inside of my amp with twisted cloth-covered heater wires.