The 38 watts is class A1 but small amount of grid current as it approaches zero volts is expected. So a driver with low output impedance is for that reason.
Since you came back I’ll update you on this thread. A friend passed away and left me his Brompton in his will. So I have two now. But I had a stroke and just walk or go on buses or trains. I’m ok walking but not confident to ride a bike. Not allowed to drive yet because I still have symptoms. If ...
Certainly the fatter el38’s wouldnt fit youre chassis. But out of all the higher powered higher transconductace beam tubes and pentodes I like the quite different el38 and genuine Mullard much more affordable, especially the pl38 @ £25 delivered from Langrex. Also falling off a log.
I had to look at the MO data for the kt77, because Ive never encountered it. Derek Rocco is selling JJ’s for £28 at todays prices buying them is like falling off a log.
What surprised me was the better distortion profile in class ab ul pp fixed bias compared to cathode bias.
If you have room for two free el34’s I’d try those.
The triode ri is 910 ohm which is the biggest draw compared to the EL84 in youre situation. S triode is also high at 11.5 mA/v when youre looking for a cathode driver.
I dont have a working valve tester but I could plug them into my el38 amp to ...
Obviously el84 is mu 19. But 5k se might be ok, pp requires 10k. But 5k se isnt the usual 3 to one impedance ratio so might be a compromise on what you could hear with more load impedance and the associated ...
I got an O level GCE in the subject, but I can't remember what the test piece was, I think brazing was involved.
My first job, at Marconi, involved workshop training, for which I an eternally grateful. T'was there I increased my basic skills and added gas (oxy ...
Big brother of 6V6; 6L6 has a mu of 8 likes a 5k load too? Isnt that enough. Also as a speaker driver 1.4 watts. Sounds pathetic but better than 6V6.
EL37 close to 6L6 has better mu of 9. BUT because its stated purpose suggestion by Mullard is as a push pull driver for a bigger output stage. So its ...