Single Ended Amplifiers


Other possible projects -
    I've got a couple of NOS EL821 pentodes.  These weren't designed for audio use but are electrically equivalent to the earlier (and larger) EL33.  They could be driven by EF86s, using the same circuit as the EF36 + EL33 "bluetube" amplifier.

Recommended anode load for common pentodes in single ended mode.
 Valve Load
 6F6, KT63  7000 
 6V6, 6AQ5, EL90   5000 
 EL33,CL33,PL33,KT61,6P25  7000 
 EL34  2000 
 EL41  7000 
 EL84  5000
 6L6, KT66, 807, KT44  2500

Schematics at