Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Wanabejimi on October 16, 2020, 09:14:53 am

Title: Reverb Problems
Post by: Wanabejimi on October 16, 2020, 09:14:53 am

I have a 6L6 Princeton Reverb build and I'm having problems with the reverb.  The amp sounds fine without the reverb driver tube in.  With the driver tube in, the signal is very low and tons of noise.  I did the audio probe and I got full signal of V1 without the driver and no signal (that I could hear) with it in.  I have 440 vdc going into the reverb transformer.  I have 80 volts on the cathode.  I replaced the cathode resistor and the 12at7 with no change.  I don't have another 25/50 by pass cap (kind surprised it didn't blow).  Could the cap be the problem?  Any other thoughts?  Thanks!  I should also mention the amp makes an audible squeal...both the amp itself and through the speaker when the b+ hits it.
I have also traced with circuit and checked with a multimeter for any shorts and I have not seen any problems.

Title: Re: Reverb Problems
Post by: sluckey on October 16, 2020, 09:28:23 am

Measure resistance between V2 pin 8 and chassis. Put meter probe directly on the socket pin 3. What have you?

Title: Re: Reverb Problems
Post by: Wanabejimi on October 16, 2020, 03:32:41 pm

2.3k

Title: Re: Reverb Problems
Post by: sluckey on October 16, 2020, 05:10:05 pm

Something bad wrong if you have 80V on the cathode. Should only be 8V. I'd look for wiring errors.