[FloridaBoy]

Originally Posted by Bombadil

I'm running an earlier Inspire, I think it is wired in Ultralinear for maximum power. Dennis has never described it as such, to my knowledge, but it produces 40% more power than his SE Pentode amps.

In my amp, my least favorites tubes are the 6V6, 6P3S-e, and 6F6. All sound very bright and have diminished deep bass. They do have great detail, if your ears can withstand all of that upper midrange energy. The high end detail from the 6P3S-e is amazing, cymbals just shimmer and strings vibrate like I've never heard before. But after 20-30 minutes the headaches come on.

As to rectifiers, while there are minor differences between types (5U4GB vs 5V4GA vs GZ34 vs 274B), within a type I can detect no difference at all. So I use all 5U4GBs interchangably, same for 274Bs, etc. I've swapped them over and over again but never hear a difference. Even inexpensive modern JJ GZ34s sound the same as expensive, vintage GZ34/5AR4s. However I believe I hear differences between every different 6SN7 that I try.

I generally use a new production Genalex GZ34 with my KT88 / KT120 / KT150 power tubes. This combination produces a powerful sound with very good deep bass detail along with smooth midrange (but not overly warm) and treble. The difference on the lowest notes from an acoustic bass guitar or a piano between the KT88/KT120 vs a 6V6 is striking.

Seems like power tube preference depends on speakers. For power tubes I prefer 6L6GA's and 6V6's with a 5R4GY rectifier driving Heresy III's with a new to me PSE with IIPS that I purchased from Beetlebum.

The input tube used has a large influence and experimenting has been very worthwhile.