이넘은 출력관에서 DC 바란스 취하는데 알렌은 ver 1 에서 처럼 초단에서 하는 것 을 권유함

이유는?

thought of...
But first up - it's starting to look pretty good, and once running could sound real nice!

But back to something that Spice has no chance telling you about, as it assumes perfect devices:

1/ either all the tubes have to be *very* closely matched (good luck!) - or you may/will need more DC balance adjustment than provided by that 100ohm Rpot2.

From some five years of building/supervising diff amps, they need the currents matched very closely in the output stage to get all the performance possible over a regular P-P amp. To provide this more readily, I would suggest moving the DC balance control to the cathodes of the 6SN7 stage - then you can tune the DC balance of both stages from one pot - which may need to be front panel adjustable.

2/ does Spice tell you haw much distortion you will get from running the 6SN& anodes at (what seems to me rather low) 62V, yet needing to swing the full drive voltage of the EL84?

3/ The second CCS will need a decent sized heatsink to remain alive for long...

Allen