Posted by bill epstein [ 65.189.211.118 ] on October 20, 2006 at 05:32:27:
In Reply to: Rocky Mountain AudioFest posted by footsurg on October 17, 2006 at 21:17:14:
The 'Simple 45' amplifier Steve Brown and I built is the best-sounding here, Denver, or anywhere. It's a direct-coupled,CCS driven, parafeed design found here:
with a few additions to the circuit by Steve.
Temporarily, it resides in this plywood case:
See the "Group Build" Forum for our respective contributions 
Ever since I heard the Yamamoto at Speakerman's house I knew I wanted that 45 tube sound. Soon after, I built the
Welborne DRD 45 which was a huge disappointment. Then I had the KR Audio VA 340 with it's 300B XLS tubes in for review and that was forgotten. I became interested again after the KR went back and came across the Simple 45 design by John Tucker and maybe, only when presented in a positive light, (hee-hee) Doc Bottlehead. I showed it to Steve and he was impressed so I opened my wallet.
It's powered by a Hammond 373BX with 5965 drivers. All the signal path is silver wired and has Audio Note tantalum resistors.
The power supply includes the constant current source and, a little of the Evil Dr. Brown's secret sauce DC to the filaments that made for extremely low hum. Behind the drivers are JJ electrolytics; under the powder coated chassis are a pair of Hammond filter chokes and a big Solen cap.
The output stage features Magnequest EXO-03 plate chokes, Obbligato oil parafeed caps and Magnequest Robin Hood parafeed output transformers.
The bias meters, suggested by Steve, are a nice touch, don't you think?
That all-important first impression is of incredible detail and ultra-tight bass control. You hear all that audiophile stuff like fingers-on-strings, the bodies of guitars, violins and cellos, the column of air pushing through reeds and clear tones of the deepest bass instruments. Voices are just sooo natural.
None of these details exist by themselves, however. They become a part of a whole that invites you to just listen to the music.
We played it through 100dB efficient open baffles and a pair of mid-90's sealed boxes. No compression or strain. Now, back at my house, I have it driving the 1812's direct through a Goldpoint attenuator to room-filling levels with ease.
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