Heater wiring rant

[lord preset]

I hate doing heater wiring with a burning passion hotter than a thousand suns. In that way I'm just like everyone else.

But I do have a serious if possibly dumb question. If it is critical that filament wires remain tightly twisted in parallel all the way up to the pins why are tubes designed so the wires have to be run to pins on the opposite sides of the socket? This seems illogical if not evil.

[nickt]

Heater wiring proves Satan exists. It's a fact.

As far as tight twisting goes I'm not sure it's necessary. If I recall Soldano doesn't even twist his heater wires and just runs two straight lines close to the chassis because it's easier.

For less pain it might be an idea to use teflon coated wire. The Mojave amps look pretty good and teflon doesn't get messed up by soldering irons.

YMMV of course

[Firestorm]

Now you can see why Fender (and everybody) liked to connect one side straight to the chassis. Not modern practice, but easy.

[xtian]

Don't have to be twisted, just tightly coupled together. Twisting just helps them stay together. I've been experimenting with 2-conductor packages, but haven't found the perfect thing yet.

[lord preset]

I have seen the Soldano straight wire technique, but it presumes that you can get wires to be straight. In my world straight lines are impossible. I use teflon wire which for all its virtues tends to be springy and reluctant to stay where it's put. I twist heater wires on a drill because otherwise they will not stay together. Of course it's possible that none of this matters at all and the "rules" are a gag. Of the amps I have built some have hum more than others but I can't say I have ever traced the problem to filament wiring.

[BLT]

Some examples of Trainwreck Express type heaters loose wiring.

[Firestorm]

If you look at Hiwatt's wiring, you'll find straight leads to the outputs, twisted to the preamps. Some of the preamps have to have less than Blencowe wiring (Hi Merlin), but they cross tightly at right angles.

I do it Merlin's way (which is a pain), but it's the first stage that matters, especially in a high-gain amp. That's why some amps go DC for the first stage only.

If you bias the heaters up to 50 VDC or so, none of this matters. SE outputs can hum, but biasing them up kills that, too.

[Stevem]

I have grown to prefere biasing up the whole string to going the full DC route!
I find that the high level of DC current when running on 12 volts does change the responce of a preamp tube, no comments so far on output tubes!

[Smokebreak]

I did this a while back. I always keep a spool of bare 22ga and 20ga. I chucked 2 pieces of 22ga real tight, in essence making a very straight piece of wire. Do that again, and you have your two straight, parallel wires. This amp was totally quiet.

[lord preset]

I did this a while back. I always keep a spool of bare 22ga and 20ga. I chucked 2 pieces of 22ga real tight, in essence making a very straight piece of wire. Do that again, and you have your two straight, parallel wires. This amp was totally quiet.

Cool. Why not do that all of the time?

[Smokebreak]

I actually don't mind doing heaters the traditional way. I'm sure I could hone my technique with this parallel method, but it does involve some twisting of the socket pins, and I wasn't entirely keen on that. Probably overly cautious though.
The next step would be to use standard insulated wire, and not twist them, AND not even worry about making them parallel. I think it was the Kitty Hawk amps that did that, maybe? My estimation is that it's more important to keep signal wires away from the AC, no matter how you do the heaters

[pdf64]

For ac heaters, Merlin's suggest lead dress arrangement seems the clear way forward http://www.valvewizard.co.uk/heater.html

[Structo]

My estimation is that it's more important to keep signal wires away from the AC, no matter how you do the heaters

I agree

[Phil_S]

I've often toyed with the idea of the Soldano type heaters. I dislike the idea of wire without insulation. I'd want to sleeve it between the sockets. That makes it look like too much work.

As for the loose loop designs, I will go one better. I've got a Gibson Minuteman c. 1966 that uses no twist at all. They simply ran the wire from socket to socket on the chassis floor and it works fine.

I am thinking the more stuff, the higher gain, you have to pay more attention.

[Structo]

I don't mind doing heaters but I haven't built many amps.

It can be tedious trying to fit those wires in the holes of the pins.