11-23-2019, 12:36 PM
I finally had a chance to update. I replaced all the power HV supply caps with the good Nichicon brand from Mouser. I didnt replace any of the lower voltage caps, but I may need to. I put new ceramic tube sockets in, which was fun since they were soldered between the PC board and bottom of the tube socket instead of opposite sides. I installed a new pair of matched Mullard output tubes and bias looks about right (-33V if I recall). Im not sure just how well they are matched tho. There is a slight difference in cathode current when I monitor, but is small. They both draw slightly either side of 50ma at idle. I cleaned all the controls and fixed the speaker terminal connector after it broke off when disconnecting. I have a couple minor issues, which one I believe is the 12AX7A preamp tubes. I have some static, hissing or whatever when I first power up, but diminishes once it warms up for a few minutes. I plugged a new short plate JJ tube (only had 1) in and it helped quite a bit, but still had some noise. It is very quiet with the 1st preamp tube pulled and the JJ tube in the 2nd tube/splitter. It is noiser with the original tube, so I have a new set of Tung Sol tubes coming. Ill see if this silences it.
The next is a low level 60/120 cycle hum that is dependent on the tone controls. Its almost not noticeable with the tone controls zero'd. So, I will probably go after the e caps in that section and on the DC line of the filaments.
The next is a low level 60/120 cycle hum that is dependent on the tone controls. Its almost not noticeable with the tone controls zero'd. So, I will probably go after the e caps in that section and on the DC line of the filaments.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44