• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

My Dynaco ST 35

So my friends I have sat all weekend and made every imaginable attempt to tame the pulses that arise. After exhausting all variations and attempts, I have now taken apart the entire amplifier and am starting from the beginning and we will see if it gets better. I will have the mains transformer tested by a friend to see if one 115V or more windings are damaged. But first it must be put together to see if it is I who have made a mistake.
 
I was thinking about 50Hz from the PT core coupling to the bell covers of the OPTs. A short while ago as I was reorganizing my system, I noticed a low 60hz buzz on the speaker I never heard before, I then realized that the RCA interconnects had worked themselves next to the power transformer core.
 
Status report, now I have put it back all together after I decided to start over and now the 50Hz is completely gone but what remains is a faint hum which is not heard until very close to the speaker (0.5m) then bear in mind that I have a pair of Altec 604E with high sensitivity.

It's gratifying but still not my preamp has decided not to be in the game so that's the next project to repair and another story. Thanks for all the help and ideas to fix the problem and improvements.

Cheers Anders