heater twist

[Geezer]

R8burst
Junior tube assistant
Posts: 24
(3/3/04 12:07 pm)
 heater twist.
--------------------------------------------------------------------------------
 I have a 69 princeton non reverb that I rewired the heaters on with cloth wire. It then started to motorboat and hum. Couldn't fix it. Then today, I untwisted the wires from the preamp tubes to the power tubes, and between the power tubes. no more motorboat (yeah!), but hum is still there. New caps everwhere, and original 2 prong cord. My question is..should the wires be twisted or not from the pilot light and 100 ohm resistors to the power tubes? Will this being incorrect induce hum?

Help is appreciated.

Tony

 
Andy Poupart
Senior tube assistant
Posts: 125
(3/3/04 12:19 pm)
 Re: heater twist.
--------------------------------------------------------------------------------
 Twisting the heater wires is the way to go. Did you make sure that you wired all the tubes up the same way? In other words, the same wire goes to pin 9 on each of the 12AX7s and the other wire goes to pins 4 & 5? Crossing them over will induce hum.

Also, get rid of the two prong cord and install a properly grounded three conductor power cord. That will quieten things down a lot.
 
R8burst
Junior tube assistant
Posts: 25
(3/3/04 12:29 pm)
 heater twist
--------------------------------------------------------------------------------
 The preamp heaters are correct and twisted. I'll do the power cord next. Thanks for the help

Tony
 
GroundhogKen
Forum Moderator
Posts: 2306
(3/3/04 12:32 pm)
 Re: heater twist
--------------------------------------------------------------------------------
 Crossing the wires on pins 2 and 7 of the power tubes could introduce hum as well. Check it.

Ken