Vac 30/30

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OldScott

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Vac 30/30
« on: 25 Jun 2023, 10:02 pm »
Does this amplifier automatically bias itself?

JakeJ

Re: Vac 30/30
« Reply #1 on: 25 Jun 2023, 10:17 pm »
I found a copy of the manual online and skimmed through it quickly, did not see any biasing instructions but there is a reference to a green LED (one for each output tube) that lights up if the tube is bad, ie. won't hold bias.  The LEDs all come on when the amp is first turned on and then go out in a couple of minutes after the circuit stabilizes.  It appears this is a fixed bias amplifier.

http://www.vac-amps.com/manuals/Manual_Ren30-30.pdf

Jon L

Re: Vac 30/30
« Reply #2 on: 26 Jun 2023, 03:12 am »
I used to have Van Ren 30/30 amp, and it's cathode-biased (self-biased).  Renaissance amps run the 300B pretty hard, so AVOID 300B tubes like Sophia 300B fake mesh tubes.