I've been building two amps for the last seven years, one SE and one PP. As I develop one to the point where it surpasses the other I remove the older amp from my main system put it on the work bench.

I believe the ultimate potential for either topology far exceeds the abilities of %99.9 of the amateur and professional amp buliders out there (and I most certainly include myself in those ranks.)

The primary disadvantage of the SE topolgy is the SE ouput transformer. The comprimise needed to balance DC power handling and good primary inductance is painful. The parafeed connection (and thus no air gap) helps a lot - but it introduces the problems of (some would say the evils of) large coupling caps.

The primary disadvantage of PP amps is that real, honest to god, dynamic tube "matching" is very rare, and possibly fleeting, as the tubes age. CCS's help a lot, but they have their own issues and colorations and complexities.

The good news is that either one can sound great, and that it's a heck of a lot of fun building tube amps! It's fun, because for maybe $300 to $600 you can buid an amp (PP or SE) that, soundwise, kicks the doody out the huge majority of commercial offerings any price.

The amp at the link below has morphed from a simple little 6SL7 SRPP driver to 6N1P (parallel sections) parafeed transformer coupled driver, parafeed output. It sounds fantastic, but it can't match the bandwidth (bass and treble) and drive/punch I'm getting out of my PP amp. The PP amp pretty much matches the midrange.

Fun times, man!

TC

• My Original SE AMP