new amp with wrong voltages

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lespaulblues
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new amp with wrong voltages

Post by lespaulblues »

Hi i built a fixed bias 36watt using el34's and an 18watt preamp same
as the trinity 18watt plexi.
With no tubes in and on standby i'm getting 415vdc on the first side of
the 32/32 can cap,which is ok for the el34's,the voltage should lower with
the tubes in.
The bias circuit is working with the trim pot.
The problem is the voltage on v1 pin1and pin6 being 369vdc and no voltage
on pin3 and pin8.
Any ideas would be helpful.
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katopan
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Post by katopan »

Pin 1 & 6 are the plates and 3 & 8 the cathodes. With no valves installed you would expect 1 & 6 to be up around the B+ and 3 & 8 to be at ground. Sounds like you're ready to test with valves in.
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