Pros and Cons seems a bit on the square side...stereo chassis seems OK to ~20W. L-C power supplies for anything bigger get too heavy to carry easily. Mono construction requires matched stuff. Can't have one channel 40V different from the other.

So, class A output stage. 15-25Watts. No rare or expensive valves. No scary voltages.

This leaves a few possibilities. I am trying to decide on the next amp project. Expanding to 813's for personal use and 'research' is one possibility. Some small, comparatively inexpensive stuff like 6V6's or 6L6's is another. The new 7591's look quite appetizing as well. The ease of driving them is not to be ignored. the question of where they like their U-L taps is probably going to be a somve by building thing. Multiple taps is no big deal with a lot of the designs I'd use for OPT's.

regards,
Douglas

Been following your group build pre. Looks like it is going to be alot of fun. Would have liked to join, but too many other irons in the fire right now.

For an inexpensive amp, with great sound, what about the:
a) Simple 84
b) Compact 84
c) PP 84 on both the Electra-Print & Chris Brady sites
d) PP 6v6 on Poinz's site.

Joe

Electra-Print http://www.electra-print.com/el84psa.html

Poinz http://audiotropic.netfirms.com/blurb1.html

Simple EL84 http://diyparadise.com/simpleel84.html

Compact EL84 http://diyparadise.com/ultracompact.html

Besides, the power diff between 80% and 95 is not a big difference. 807's are not out of the runing yet, they fall into good 6L6 cassification for me.
regards,
Douglas

EL84 is getting into the sought-after/expensive category for the good ones, so I put it a distant second to some other choices.
regards,
Douglas

That said, I did get a chance a while back to audition some "high end" equipement which included a SE 845, SE EL34, PP EL34. The amp that caught my attention was the PP EL34. I really enjoyed it. It could have been a system syngery thing, but I did have time to sort that out. Sooo, I've been looking at a lot of PP designs.

I've been looking at the Nutshell HiFi site, Bruce Rosenblitz site, Vacuumstate Electronics, Gary Pimm, as well as the sites listed earlier.

Nutshell Hifi favors PP DHT's. The others are into PP Pentodes and OTL's. I have favor PP Pentodes due to what I HAVE heard, which isn't much. Beside I figure you get more bangh for the buck here on the "dark side." So my earlier post.

What about Cris Brady's 6AU6 style SE input, autoformer coupled to a PP 6V6/6L6 output stage. The OP points would need to be wporked out, but it should hold its own with ALL comers.

Using Heyboer power tranies, and Electra-Print autoformer/output iron should be cost effective.

Joe