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Bad Voltages in my Princeton Reverb?


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5/22/2000 4:48 PM
Mark
Bad Voltages in my Princeton Reverb?
I am getting what appear to be bad or strange voltage readings in my SF Princeton Reverb that I need help interpreting.  
 
When I measure the voltages after the first .022 coupling cap (feeding the 3.3M/10pf reverb splitter network), I get some DC fluctuating between 4mv and 15mv with the amp idling. When I play a note, DCV shoots up to several volts. Its my understanding that there should only be AC after coupling caps and no more than 5mv DC. I replaced this cap with several new O'drops but I get the same results. Is this normal? Incidentally, the distortion is somewhat buzzy, with garbage noise intermodulation products - not smooth & creamy.  
 
When I measure the cathode and plate voltages on the vibrato tube, the readings don't appear on my DMM for about 12 seconds. Meanwhile the meter picks up these readings from all other tubes almost instantly. The readings are in spec and the vibrato does work, but it looses definition at high volumes and you can hear clicking sounds from the output tubes with the Intensity on 10 and the Speed on 1-5. Clicks are not amplified though, thank god. Is this normal behavior or is something off in my vibrato ciruit? (Swapping the tube didn't change anything).  
 
Thanks in advance for any help offered!
 
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5/25/2000 6:10 PM
Gil Ayan

Mark, some of the measurements you're trying to make involve circuits with rather large time constants, so it WILL take some time for the meter to reach it's steady state value. Hang in there. :)  
 
Gil
 

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