Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: shooter on April 24, 2015, 09:18:55 pm
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Ecstasy 5.7, besides being one of the east coast’s best classic climbs, is a continuing project. I up-graded the preamp design, from a 4 gain Hiwatt spaghetti , to the plexi-ish type build on turret board. The PA is from a Clubman sorta.
I started with an AU7 for V1, which I like better than the AX7, but I think the players will prefer the AX7 for the cruncher bight the extra gain yields. Did my standard tests before playing, the Pwr at the DL measured about 21Wrms, plate 433, G2 267, bias about 16.3vdc
I’m getting about 15.8vac-rms to G1 with the AU7, didn’t test the AX7.
The sound is very clean and crisp and loud up to about 8 on Vol, then it sounds like you been grabbed and squeezed exponentially to 10! The treble was pretty shrill, I added a .01uf off the bright V1a plate and that tamed it. the bass is spot on 1 to 10 and I’m not good enough to say what mid does. Sounds very good paired with my spaghetti Revibe. I tried the Revibe into the RET but there isn’t enough gain to drive the PA
I’m 0 for 2 now on turret board design! The 1st one was fine…as long as Doug mounted the turrets on the “bottom”, this one was a “mirror” of what I thought! So I ran the wires under and siliconed them so they stayed put. I’m running it into a 2X12, late ‘80s cream faced celestian paired with a new eminence legacy.
the blank turrets are for the PA section but it was already wired and working. The chassis has a spare octal and 1/2 AX7 for the future.
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Update:
Finally got a professional to evaluate this amp, I Got an "A" !
"full on Rock amp that works from Hendrix to Clapton, Don't change Anything"
and the same answer I get from most musicians; "Dude If I had the money....." :icon_biggrin:
thanks for all that contributed to getting me where I am :thumbsup: