Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mikhett on March 27, 2011, 07:40:15 pm

Title: ampeg reverbrocket 2 ps voltage too high???
Post by: mikhett on March 27, 2011, 07:40:15 pm

I just finished rebuilding a 67 ampeg rr2 amp.this is the one with a 12ax7,6u10,7199 and a pair of 7591s.Im getting 380 volts at the first 2 filter caps then 340 at cap"C" and 300volts at cap "D".There should only be 200 volts at d .It feeds the plates of the 12ax7 and one side of the 6u10.I measured the 1k,10k and 470 ohm ps resistors and they check out right.im checking the wiring in the ps section but everything seems right.this rebuild was a nightmare as i used a 43 pin 17 inch turret board as the ampeg is loaded with components due to the reverb.HELP! Thanks Mike

Title: Re: ampeg reverbrocket 2 ps voltage too high???
Post by: PRR on March 27, 2011, 08:58:06 pm

> There should only be 200 volts at d .

That is probably incorrect.

300V-330V seem more likely.

How does it play?

Title: Re: ampeg reverbrocket 2 ps voltage too high???
Post by: mikhett on March 28, 2011, 07:41:03 am

Im checking with tubes removed,and dummy speaker load before installing tubes.

Title: Re: ampeg reverbrocket 2 ps voltage too high???
Post by: LooseChange on March 28, 2011, 07:51:55 am

All voltages will be high with no tubes... Need tubes to check voltages.
Dummy speaker load not needed with NO tubes.

Title: Re: ampeg reverbrocket 2 ps voltage too high???
Post by: sluckey on March 28, 2011, 07:54:29 am

Quote

Im checking with tubes removed

In that case, all plate voltages will be high because there is no load on the power supply. No plate current is flowing, so no voltage drops across the B+ nodes or plate resistors.