KT120 PPP Issues/Improvements

[gabdx]

wow, this is very sad! If you need the amp to go full to 100W without distortion like it should and paid for...

I have the 5k loaded 1950R of hammond (for experimenting) and I get easy 80 clean watts with a pair in UL.

a pair of 6sn7 should be able, like everyone mentioned earlier the voltages are penalizing your available output.

600+ at output 70ma per tube, and 200V + for the drivers, now why lowering to 33k and still no power...

I am no expert , but grid needs 50k to ground , now it looks like you have 150K and more...

 

[gabdx]

B+ too low for KT120 , no matter what modify you do can not increasing output power except. Change Tube rectifiers to Solid rectifier or increase AC voltage before GZ34. I design KT88 push/pull amplifiers at B+ 475~ 480V after heat up when working. KT120 need more higher B+ , It can be more than +500V.

yes, use a quality bridge that can take the voltage and use a softstart module