Well, there are many "proven" topologies, obviously, as few people have yet build Seth there will be limited specific feedback.

Your options are:

1) Balance the currents in the cathode circuit using seperate cathode RC circuits (previously suggested by Jeff)

Pro - grid circuit remains undisturbed
Con - requires the heaters of the valves to be separated and the full AC signal current passes through the cathode RC, not only the error signal as in the original Seth (in my experience this sounds a LOT worse BTW).

2) Balance the currents in the cathode circuit using a Pot between the cathodes (Marcel/Clovis style)

Pro - grid circuit remains undisturbed
Con - a balance pot between the cathodes introduces local degeneration, increasing output impedance and again likely impacting notably on the sound, especially as good sounding high power pots are rare, the full output AC signal current again passes through this pot.

3) Balance the voltages for the Grids

Pro - leave the original Output circuit as is, IMHO it is of the best sounding solution that way (better is to use "ultrapath" cathode bypassing, WECO 86/92 style or the semi-fixed bias shown in my Amp and many vintage types which are really the same, functionally).

Con - requires a phasesplitter choke that allows the halves to be separated to inject a few volt positive (in my example with the Amp balanced with perfectly matched valves around 2.4V into each grid) into the grid circuit so that varying this voltage balanced the current, sonically IMHO though the best option

Either approach to balancing the valves requires significant changes to the design and balancing the current in the cathode circuit will change the sound of the design.

톨(Thorsten)씨가 각각의 방법에 대해 썰 풀어 놓은 것입니다. Pro & Con(장단점) 형식으로 잘 설명 되어 있심다.

그림의 회로는 톨씨가 권장하는 방법으로

1) 초쿠에 분리된 center tap
2) 초쿠 센터 사이의 VR은 그리드 전압을 변화시켜 DC balance
3) 캐소드의 VR은 hum pot 로 추정합니다.