Type 42 single ended ideas

[oleg___g]

Screen supply schematic:

5k OPT is very good for 42s in triode mode.

 

[bigbargain]

Triode 42's. Gonna be some flea power. BUT the good news is that I scored some Heresy's a week ago! See my earlier posts in this thread - I missed a pair. But I guess 80 year old tube karma is with me so I got a second chance and I was quicker this time.

Cathode biased but I don't see a cathode bypass cap. But see a cap screen to cathode. Is that correct?

 

[oleg___g]

42 tube in triode is about 1W of nice sound. In pentode mode more than 3W.
I know two options for grid capacitor - to ground and to cathode. I like to cathode. You can try both with good film capacitor about 4-8uF.
Cap in the cathode at your discretion. Try both options too.

 

[bigbargain]

Thanks. Will do.

Do you think the cathode bypass cap needs to be high quality? I think its more of a filter cap like whats in the PS - holding voltage steady. Right?

 

[oleg___g]

In my opinion all capacitors need to be high quality.
Waiting for results. And be sure to try 36 in triode mode.

 

[maxchau]

42 tube in triode may be flea power but I have used it to power a pair McIntosh XRT18s without any issues and the sound level is loud enough for normal listening. Driven by 6sj7s, the sound quality is not too far from that of the 45s.