Pas3 distortion after bypassing tone controls

I bypassed the tone controls using http://www.audioregenesis.com/documents/PAS%20Tone%20Control%20Bypass.pdf after having not used it for a while.

I also have an SDS Audio labs power supply board installed. All tubes test very good on my Sencore Mighty-Mite II

I now have quite a bit of distortion playing records (into a ST70, new tubes).

I measured voltages and found only 103 VDC on pin 1 of one of the 12AX7'S on PC6. Other voltage readings are pretty close to aim except maybe pin 6 of the 12AX7's on PC5 which are 191.5 and 201.

Is that enough to cause problems?

-Mark

intotubes wrote:I bypassed the tone controls using http://www.audioregenesis.com/documents/PAS%20Tone%20Control%20Bypass.pdf after having not used it for a while.

I also have an SDS Audio labs power supply board installed. All tubes test very good on my Sencore Mighty-Mite II

I now have quite a bit of distortion playing records (into a ST70, new tubes).

I measured voltages and found only 103 VDC on pin 1 of one of the 12AX7'S on PC6. Other voltage readings are pretty close to aim except maybe pin 6 of the 12AX7's on PC5 which are 191.5 and 201.

Is that enough to cause problems?

-Mark

No, voltages seem to be withing "margins".
No other chages ?
If the distortion is only when playing vinyl i suggest you replace the ecc83 on pc6 with new ones.
And, clean the needle !!

also clean the selector switch, especially if it's an original !

intotubes wrote:I bypassed the tone controls using http://www.audioregenesis.com/documents/PAS%20Tone%20Control%20Bypass.pdf after having not used it for a while.


-Mark

I had a similar situation a few months ago.  Turns out my cartridge was gummed up.  I cleaned it with water and a brush and the distortion was gone.

Dave

Thanks for all the help! I have some things to try now. I have a second cartridge/headshell I can try as well. One thing I feel a little stupid about is I didn't try a CD to try and isolate the problem.

-Mark

*Update*

Tried a CD, no distortion. Cleaned the needle, played an LP. Sounds good.
So I don't know. Dirty needle? I removed the tubes an reinserted a couple times. Dirty sockets? It's a new preamp/amp/speaker combo, maybe not used to the sound? Seems like there's more gain (loudness) than before but maybe I'm comparing amps. I haven't got many miles on the ST70 with KT77's so its a lot more power than I'm used to with the PAS3. Also the JBL L300 have a different sound than my Model 19's. I'd say this set up is brighter than the Fisher KX-200/Model 19 combo. Both set ups sound pretty good though.

Thanks for the advice!

-Mark