I found a PAS3 preamp I forgot I had, that has been residing in storage for the last 30years.
It's in decent cosmetic condition, so I decided to clean it up, give it a set of tubes from my stash, give it a gentle wake up with a Variac, and check out the voltages.
My goal is to sell it in good operating condition.
I didn't expect the can cap to still be good, but with a very gentle awakening it responded without heating up, and the background noise level is very low without any hum present.
I replaced the selenium rectifier with silicon diodes.
I cleaned the sockets, controls and jacks, and the tubes I put in all test strong.
I've installed upgrade packages from Curcio and Van Alstine back when I acquired this preamp, but my goal is to have it original, presentable and running properly when I sell it.
It sounds as I expect a PAS3 to sound, in fact none of the control pots exhibit any scratchiness after I gave the a Deoxit Faderlube treatment.
So I have finally gotten around to my question:
I am using the voltage chart from the original Pas3 assembly manual to check voltages at the can cap and the tube socket pins.
I did the check with 120V line voltage since the voltage chart specifies 120V.
The 1st can cap terminal is just about at nominal voltage (405V).
I installed new dropping resistors on the can cap per the schematiic.
The 2nd can cap terminal is about 25V below nominal (355V).
The 3rd can cap terminal is about 45V below nominal (330V).
The 4th can cap terminal is about 10V below nominal (210).
I realize the low voltages are near the +/_ 10% tolerance often cited for tube equipment, but when I check the plate voltages for the line and phono sockets I am well beyond the 10% tolerance.
On the line board I was 65V below nominal (200V) for pin6.
I calculated what the 10K dropping resistors for the 1st two terminals on the can cap would need to be to get nominal values and added parallel resistance needed to get there.
So I now have plate voltages on the 12AX7's at nominal or within 10% high.
I'm thinking that the schematic either has the dropping resistors wrong or the pin voltages wrong.
I've done some searching on the web and don't see anyone else mention this issue.
So there are lots of folks out there who have worked the PAS3, has anyone seen the voltage anomaly with the schematic?