Heater Wire Question

[Jman]

Wanted to see if anyone has a recommendation for heater wire that can be used. I have found the 18 guage green cloth covered wire is hard to work with and sometimes cracks the solder joint. Is it OK to use 20 guage or even 22 guage stranded pvc 600v wire? Thank!

[loudthud]

On a 5E3 I'd use #18 from the pilot light to the 6V6s and #20 from the last 6V6 to the preamp tubes.

I've found that #18 can have excessive voltage drop on long runs in 4 power tube amps. I tried #16 teflon aircraft wire and it worked well. Since you need two wires connecting to most of the tube socket terminals, both wires need to be inserted into the terminal and crimped tightly with needle nose pliers before applying solder. From the last power tube in the string, #18 or #20 can be used for the preamp tubes. On tubes like 12AX7 where pins 4 and 5 must be tied together, I prefer to make a jumper out of resistor lead between the socket pins and solder the wires to that.

[billyz]

I have been using 20AWG Teflon coated stranded wire for all heater runs in the amps I build. No problems and I can fit two wires to one tube pin. I do find it easier to use a small jumper on the preamp tubes pins 5 and 4. Or I wire one side to pin 5 and the otherside to pin 4, then solder those together. I use the stranded wire only, solid core does tend to break. Twist them in a drill and vise.

I wire then from the pilot light. here are a couple of shots. I do recommend the teflon, it will not melt when you try to solder it.

[Jman]

Thanks for your help!

[Jag]

On tubes like 12AX7 where pins 4 and 5 must be tied together, I prefer to make a jumper out of resistor lead between the socket pins and solder the wires to that.

Honestly!!! Why didn't I think of that :0)! Sometimes I miss the most obvious things for YEARS!!!