New 18 watter comes to life!!...........sort of...

[Brian]

I finished my amp last night and fired it up and everything appeared to work until I turned the tone to zero on the normal channel. I am getting a loud squeal when it is at this setting. If I turn the knob a tiny bit clockwise it goes away. Also if I plug a guitar cable in it goes away even when I return the tone to zero. I have checked the wiring on the input jacks, thinking I did that wrong. It appears to be correct. Anyone have any ideas? I do have the tremolo channel working and it sounds great! I dont have a cabinet for it yet but I have it plugged into my High Octane's speaker, a G12H30. So far it sounds really nice. I have not cranked it up though. I will be using the amp as a 1x12 combo maybe with a Weber or a greenback, havent decided yet. Anyhow, I will post some pics once it is all dialed in.

Thanks,

Brian

[Graydon]

I just put a small resistor (less than 500 ohms) between the bottom leg of the tone pot and the cap. That simulates the pot being not quite on zero and that seems to solve the problem just fine.

[Brian]

Thanks Graydon, that did the trick. Now that I listen closer to the amp it seems there is an intermittent, very soft rustling sound coming from the speaker. Any thoughts on this little problem? Also, I am getting a B+ of 355 volts. Is that too high? I am getting about 14 watts dissipation per tube according to my calculations. Could it be my tubes cooking?

[markh]

14 watts is a little high, but still OK in the "old English amp with way hot bias" category.

Noise: Double check all your solder connections. What kind of resistors did you use? Try removing V1 and see if it still does this, if so, try V3. If removing either gets rid of the problem, try replacing the suspect tube, or if you don't have any backups (shame on you ) try swapping it with the phase inverter, V2.

--mark