Schematic for Tubeworks Pro Valve 60

[Roy Blankenship]

I need a schemo for a Tubeworks Pro Valve 60. This is the second one I have
encountered that is running 500 volts on the plates, the bias is -47 volts,
but the tubes are drawing 60 ma. There is some sort of interstage tranny in
the bias circuit, anyone? The amp is actually new, never sold, from a local
dealer, but it "done blowed up".

The other thing I am looking for is an opto for a Gibson GA-20RVT. There
used to be a thing by Clairex called a CLK320, but Mouser doesn't have any.

Thanks in advance.

Roy

[Robert M. Braught]

Post by Roy Blankenship
I need a schemo for a Tubeworks Pro Valve 60. This is the second one I have
encountered that is running 500 volts on the plates, the bias is -47 volts,
but the tubes are drawing 60 ma. There is some sort of interstage tranny in
the bias circuit, anyone? The amp is actually new, never sold, from a local
dealer, but it "done blowed up".
The other thing I am looking for is an opto for a Gibson GA-20RVT. There
used to be a thing by Clairex called a CLK320, but Mouser doesn't have any.
Thanks in advance.
Roy

Hi Roy,

Warranty was easy to set up w/ Tubeworks/GenzBenz, as I recall. Not
the highest paying, but quick. They supplied us a service CD that's
got that schematic, a 1.6meg scanned PDF single page. Doubt you'd need
it, really, but let me know (direct); if you'd like, I'll temporarily
upload it to my site.

It indeed has a driver transformer (ala Gibson GA-5T Skylark or Fender
Musicmaster Bass) shown on the schematic (of course those are tube
driver circuits, the Tubeworks is SS driven using a TL072!); secondary
center tapped for the bias supply connection, no bias voltage
measurement on the schematic but the bias voltage is 'set' by a 1N5261
(zener.) The plate voltage they indicate is 458VDC (at ? AC input.)

FYI the output stage negative feedback connection is *post* the
impedance selector switch, instead of 'permanently' wired to impedance
X (so it would appear to me that if the impedance selector switch was
a bit flaky, this thing could *really* flyback!)

Glad to know you're still 'kickin'!

(Sorry, no direct help w/the Gibson trem unit. FWIW I've built them
using 2~3 photoresistors in series, correct lamp etc.)

Cheers,
-Robert
QTS
http://www.Braught.com
real email addy : ***@NoSpamBraught.com (remove NoSpam to reply :
Duh!)