Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on August 29, 2023, 09:18:08 am
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does anyone make molded heater wire? it occurs to me this would make it alot easier.
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It's called lamp cord. Buy it anywhere.
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Most builds can indeed get away with side-by-side routing of heaters wires. I've done it, and Sluckey has a photo of a beautiful build with such heater wiring. Hoffman doesn't bother with on his BJ tube board https://el34world.com/Hoffman/Blues_Junior_Tube_Board.htm (https://el34world.com/Hoffman/Blues_Junior_Tube_Board.htm).
But it is also true that twisting your heater supply wires is less prone to propagating heater hum to nearby signal wires.
It's undeniable that twisting your heater supply is a mild pain. But I stress the term mild here.
I'm quite sure there are many ways to accomplish the goal. You could purchase Cat 3 UTP and liberate the twisted pairs from within -- these are normally 24ga solid. You may or may not be comfortable with 24ga heater wires, but -- recall the ampacity for these is stated for bundling purposes most often, and these wires are hanging out in the breeze and should not overheat.
Or, use the famous electric drill method for 22ga (what I use) or 20ga wires. I clamp two wires together in a vise, and then the other ends in my drill chuck. You have pull them tight enough so that the wires don't kink when you begin the twisting with the drill. Twist them tight -- and take care that they don't kink when you undo the chuck.
I have become a fan of routing heater wires at the lower back corner of the chassis. I orient the tube sockets so that 2-7 (octals) are at the back, and 9 is at the back for the noval sockets. This allows me to route the wire to the 4-5 straight across the top of the socket between the 1 and 9 pins. I have not had problems with this method, even in high gain situations. I'm not sayin' this is the best for everyone! It works for me.
I may look around for some fancy lamp cord, though.
Cheers.
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Not really what you asked about - but I sometimes use this twisted pair https://www.amplifiedparts.com/products/wire-18-awg-hook-twisted-pair (https://www.amplifiedparts.com/products/wire-18-awg-hook-twisted-pair) for the power tubes and lighter gauge for the preamp. But mostly I use the drill twist method. Its easy, looks good, and by using two colors you can keep track of the pin connections.
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note on stranded wire, triple check there are no individual stray "hairs", they have a nasty habit of touching adjacent pins, components, they are real small, easily missed when looking over your work.
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Not really what you asked about - but I sometimes use this twisted pair https://www.amplifiedparts.com/products/wire-18-awg-hook-twisted-pair (https://www.amplifiedparts.com/products/wire-18-awg-hook-twisted-pair) for the power tubes and lighter gauge for the preamp. But mostly I use the drill twist method. Its easy, looks good, and by using two colors you can keep track of the pin connections.
yup i've used that. some rigid stuff
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does anyone make molded heater wire? it occurs to me this would make it alot easier.
No.
You can't twist them.
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I had a spool of this from a non-amp related project & I have used it a few times for heater runs.
It twists better than you might expect...drill method anyway.
2 colors too...
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I think the Marshall style method of routing the heater wiring to the 9 noval sockets makes twisting the heater wires in the sections between the sockets pretty pointless
eg (https://i.ibb.co/KjXNLYS/IMG-2877.jpg)
the black wires sweeping around the outside of the socket to pin 9 create a large magnetic field.
Provided the other wires, especially grids, are kept well away from them, all is generally fine.
So if the heater wires between the sockets aren’t twisted, it’s no big loss.
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does anyone make molded heater wire? it occurs to me this would make it alot easier.
No.
You can't twist them.
i keep reading over and over twisting isnt necessary. soldano dont twist em. i rather not twist. also i always run dc heaters
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Never a need to twist DC heaters unless your ripple current is outa this world!
Twisting AC heaters was a pain until I learned a system and stuck with it. Now, no big deal.
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does anyone make molded heater wire? it occurs to me this would make it alot easier.
No.
You can't twist them.
i keep reading over and over twisting isnt necessary. soldano dont twist em. i rather not twist. also i always run dc heaters
I'm probably wrong about the pair of wires you show.
I have always found it very easy to use two wires.