New Build

[JimiB]

Well I fired her up last night. Pretty impressive to say the least. I need to sort some things out however. The bias wont go below 42mA which is a little hotter than some seem to like. I'm gonna replace that 220K with a 150K.
I've got a weird sound that I hear best when I play single notes and it comes in after the initial attack, sounds kinda like tube rattle. I'm going to see if lowering the bias helps.
Also I'm getting some ghosting with EL34's. Didnt notice it with the 6V6's.
I would love to hear some lead dress info, if someone like Paul Ruby would like to expound. I followed the pics as close as I could but I would like a little more understanding.
The amp dosent have a bottom plate yet. I was setting it near the cab (4x12 with weber 75hZ 1230's) but not on it.
I used shielded wire for the run from the input as well as back to the treble pot.

[UR12]

The 150k should take care of your bias problems. It will be interesting to see if the bias fixes you ghosting. If you can't get figured out post some pics and maybe some of us can help. The preamp tubes on this amp can do some funny things so you might want to swap them around or try some different ones. What tubes are you running.

[JimiB]

I put a 1M in parallel with the 220K and that was perfect, now I have a very usable bias range. I set the power tubes (new winged C EL34's) to 34 mA and it is absolutley amazing. The tube rattle sound (i think it was crosover distortion) is gone. The ghosting is partly the cab. I swaped preamp tubes till it was better RCA 7025 in V1 sovtek 12AX7WB in V2 and V3. I can't hear the ghosting at all into my 2x12 with classic lead 80's. I'm also using a Trainwreck Airbrake.
Wow very inspiring.

[philmanatee]

I was getting a low bass rumbling whe I backed the guitar volume way down. I plugged into another cab and left the amp on my cab and it was dead quiet. It's amazing how sensitive these are. Phil

[Allynmey]

I noticed that the amp got noisier when I put it in the cabinet. I will put a shield/cover on the bottom of the chassis.

Allynmey

[JimiB]

I've still got a little ghosting. Hmmm anybody have any ideas?
My experience in the past has been that ghosting is due to lack of filtration. Could it be due to anything else?

[mlp-mx6]

My recent fix for a ghosting problem was 2-pronged.

I was using a 50-50 dual-cap for the plate and screens, so they shared a ground. I installed a separate cap for the screen supply and isolated the ground connection from the plate cap ground connection. This accomplished 2 things - 1) more filtration on the plates, and 2) separated the grounds for plate and screen. My hunch is that #2 was the more important change.

HTH,
Michael