Recent content by Outthewazoo

Thanks again.

Sorry meant 0.072 vDC bias.....not 0.72 vDC.

I agree that those pots would good, particularly to lock down the bias settings! Just a touch of a screwdriver can make a big change in the bias voltage (current) to the power tubes. Do you usually set a SVT with 6146Bs at 0.72 v bias per the Ampeg schematic?

So after re-tracing the circuit with low line ac, I found that the bias pot on the problem bank (which was showing a decent sweep range) is shorting the bias current to ground, which "flipped" it from negative to positive. That appears to be the problem! All components are ok. Replaced the...

Thank you for the advice! The bad bank is the V4-V6 power side. At full line AC (allowed for a very short time), the 6146Bs on that bank will red plate and the amp will hum badly....it doesn't like positive bias voltage....obviously! I think this is what caused all of the issues, but why? V5...

I'm working to repair a very early (~3/1970) SVT Blueline with 6146B power tubes. The amp blew one of the 6146B tubes and took out most of the plate resistors (10 ohm), grid resistors (22 ohm), and the 2 bias test resistors (1 ohm). Traces on the board were also burnt along with one bank of...

Hey everyone...wanted to join in on the AIMS thread, too, since there is limited information available on these amps. I picked up an ~1972 AIMS VTG-120 about a month ago in amazing, all original condition. It the "personalized guitar: 6x10 at 120 RMS model. It appears not to be used much at...