OK - I stared at the hot looking Poseidon board all day at work, nice job Shannon ! Decisions, decisions ... time to listen.
When I got home - I hooked up my Dynaco MK-III's - they have the "Brand N" boards - in fact - my MK-III's and ST-70 are the poster children on the "T" web site. No boutique parts - just the Xicon caps.
Test conditions for all amps ... bass heavy music from my new favorite source - a Polk XM tuner on Channel 84 - "XM Chill" which is like slow electronic something or other ... I like it. Feeding my Adcom GTP-500II with the contour button in and out for testing, but tone controls out. Into a pair of Klipsch KSB 3.1's No, I didn't warm each one up for an hour or anything ... just plug and play for 10 minutes.
MK-III's - Well - they sound pretty nasty - tubby, vibrating bass and not very clean at all. The worst out of all we will talk about here. Pillows over the speakers compared to the others. Probably time for new tubes - the Magic Marker on the sides says 6550 6/18/73 ... might be accurate ! (and it won't wash off) I rebuilt everything else - but no new tubes.
Next:
Dynaco ST-70 with the "Brand N" driver ... just as tubby bass, not all that clean. Low on the list. The EL-34s are new Valve Arts.
DiyTube ST-35 ... better bass, more open sounding than the old Dynacos.
Dynaco ST-35 - better bass than the ST-70 or MK-III's ... but not as clean as the DiyTube ST-35
Dynaco SCA-35 - sounds pretty much like the Dynaco ST-35 - probably a little cleaner. I replaced the coupling caps and put new JJ EL-84's in it recently. Pretty good sounding. Not as much bass as the others.
DiyTube ST-70 clone with Heathkit AA-100 iron and new 7591's ... ahhh ... more like it - cleaner bass - open sounding - more listenable. # 2 place Obviously a lot of kick.
The winner ... and who knows why ...
832A push pull amp I built recently ... solid bass - no tubbiness - clean midrange - very listenable. The bass seems to have a faster release time (to use an audio processing term) All around more kick and less muddiness.
OK - while I'm at it - I'm going to hook up my big azz 60 pound 300 B amp ... I know it's not PP - but it's here in the room already.
I'm back - I will agree with Eric in McKinleyville to an extent - complex music gets muddy. Solo instruments and voices sound pretty good. Solo bass compares well with the ST-35's. Still a pretty listenable amp. Disclaimer - this thing cost a small fortune to build, I may be biased.
While I'm at it - I'll drag the huge Velleman K-4000 up here ...
It's actually lighter than the 300B ... PPP Svetlana EL-34's ... mids and highs are nice - bass is pretty tight. This one ranks pretty high, lotsa kick - I guess so, they call it 95 watts per channel. First time upstairs on these speakers - pretty nice. Bass still isn't as clean as the 832A.
No real reason I did all this - I just couldn't believe my MK-III's sounded as bad as they did ... so I kept going. Bottom line - I need to learn to tweak ... I'm on the way.