I finished the build today. All I can say is OMG! Simply amazing. Absolutely no hum. There was a very noticeable background hiss though. That hiss turned out to be due to the stock Russian 12AU7A. When I pop in any other input tube the background hiss disappears and the amp is DEAD SILENT! So the stock 12AU7A goes to the junk pile/trash.
Now the real fun begins. Listening to all my music again.
I have several input tube choices to audition:
Sylvania JAN 6189
RCA Clear top 12AU7A
Amperex Bugle Boy ECC82
JJ ECC802S
and several 6SN7GTA and GTB as well. I will also soon have a RCA red base 5692 I just scored from eBay.
For the output tube I have several pieces of pristine 1955 RCA coke bottle JAN 6AS7G.
I just listened to a bit of Diana Krall - Live in Paris, JS Bach - Suite for Solo Cello #1 - Fournier and Gregorio Allegri - Miserere Mei. Nothing is broken in yet and it all sounds great.
I added a few new pics. First shows the stuffed box. Everything did fit.
The second shows it running with the stock tubes.
@PB - Thanks for the 47k resistor suggestion. I did notice an imbalance at the very low end of the pot. It's only the first 10 degrees or so. If I find myself listening at those low levels I will then add the 47K resistors.
« Last Edit: November 22, 2012, 07:20:06 PM by davew »
Dave
Marantz SR6006 -> Stereo SE EL34 Power Amp (home built) -> Klipsch RF-15
Crack -> Sennheiser HD650