100 Watt Plexi Kit Transformer Super Low Voltage?

planetjimi · Post by **planetjimi** » Tue Aug 07, 2007 11:48 pm

Got my kit together and I must have gotten one of the power transformers that was underwound.
With the low voltage taps my b+ is 366v. Is this to low? Will the el34's get pushed enough with this voltage?
Thanks

rockstah · Post by **rockstah** » Wed Aug 08, 2007 1:47 am

checked the bias? perhaps the tubes are drawing too much current.
36mA would be 60 percent max plat disapation with 400dcv on the plates.

if your amp is biased at 46mA ro even higher i could understand the b+ reading u r getting.

edit: we are talking about an amp with tubes in it and u are getting this reading?

planetjimi · Post by **planetjimi** » Wed Aug 08, 2007 12:49 pm

Hey Mark, this is plexi #2. Just finished it. The reading are with tubes in. With tubes out it's about 376. When I first had it together I had the high voltage taps on and was getting around 476v. Now I hooked up the low voltage taps and the b+ is around 366v. I changed the resistor in the bias circiut to acommodate the lower voltage I have it biased at 43ma. I'm wondering if 366v is even enough to make the el34's sweat?