by Ty_Bower » Mon Jun 07, 2010 8:28 pm
Wow. Really nice rebuild work you've done there. New sockets, new connectors, New Sensor Gold Lions, K40Y caps, everything is redone. The chassis cleaned up perfectly, and the transformers look every bit as good as they must sound. I'd figure these amps are ready to go another forty years.
I really have fun with my Mark III. They are as close to a bottomless pit of audio power as I will ever get. The big Dynacos don't shy away from anything, they never seem to run out, yet still have a tangible delicacy when played gently. It's sorta like the proverbial iron fist in a velvet glove. I hope you enjoy yours as much as I do mine.
I might suggest you look at where the UL screen taps connect to pin 4 on the power tube sockets, and think about adding a two or three watt 100 ohm carbon composition resistor there. There's a thread or two around about the screens and the abuse they must suffer. If you've upgraded the supply capacitance, adding a hundred ohms at the screen might be the difference between a short unhappy tube life and many thousands of hours of audio bliss. Use carbon comp resistors here because they can't catch fire and burn like a film resistor might. Keep an eye on the line voltage, too, if you can. I think the Dynaco manual said 117 VAC was design center. A high line voltage not only affects B+, but also heater voltages.
The only other thing I might add would be UF4007 diodes at the rectifier socket in series with the tube's plates. I meant to put these on mine and haven't suffered any ill consequences, but it is a simple, cheap, and inaudible method of extending the life of expensive 5AR4 rectifier tubes.
Last edited by
Ty_Bower on Mon Jun 07, 2010 8:51 pm, edited 1 time in total.
"It's a different experience; the noise occlusion, crisp, clear sound, and defined powerful bass. Strong bass does not corrupt the higher frequencies, giving a very different overall feel of the sound, one that is, in my opinion, quite unique."