I think i have seen this in Jean Hiraga's book , la maison de l'audiophile used many penthode - triode designs using

Western electric tubes in general .The only thing i dont like to much is the automatic bias .

please note this amp is likely to hum slightly .

i suspect the diode rectification is because the first 2 powersupply caps are quite large to kill ripple .

 

Copyright 2002 Benny Glass webdesign for info : sales@diyparadiso.com