Clip of my amp on YouTube

[Tdale]

I posted a short clip of my amp on YouTube. If any of you care to watch, and especially listen! I'd be happy to hear your comments.



The camera has a pretty sensitive micropone, so the initial humming when I turn the master up, isn't as bad as it sounds. But when I turn the Drive and Level pots, it's almost worse than it sounds like!

The switch I flip on the back side in the end, is the OD/Clean (switching to clean)

What is wrong?

http://www.youtube.com/watch?v=bnfNaOuJy_I

[Icetech]

since the sound goes up with the OD and is still there in the clean i would think you get getting that noise in the first tube, own a scope? and that is crazy hum... i didnt expect that much, although you said the camera is sensetive..

BTW... mine will hum like that if i have the soldering iron on closer than like 5ft... they are real touchy to things like that... flourescent lights also..

[Tdale]

In clean mode, the noise gets much lower. I was closer to the speakers when I flipped the switch, so that's maybe why it's sounds pretty bad on clean mode too.

Tommy

[Icetech]

noise totally disappear without tube1 in?

[BobW]

I don't know what the standard power frequency is in Norway, but that sounds like 120 Hz, and it's definitely a power related problem.

Temporarily cover the top of the chassis with a shield such a window screen, obviously don't allow the screen to short to any components, and no the fiberglas type won't work. This should tame the noise quite a bit, since you've provided what's know as a Faraday cage. This shields out any outside noise - any noise conducted through the power line.

If that doesn't work, check your OD grounds and OD filters. hth Bob

[Bob-I]

Check that all the grouns have only one path. From the wires shown in the vid it appears that there may be some grounds with more than one connection to ground.

The way I check is I disconnect the ground wire from the chassis, then check at the component, I.E. the cathode, using a meter. If you still have 0 resistance between the component and the chassis, you may have a ground loop.

[Tdale]

There shouldn't be more than one ground point for all the components... but I could check. I have one bus along the pots and a small bus along the filter caps, which both connect to the chassis at the PT screw. Also there are 3 other wires connecting to that screw.

If I pull V1, the noise is still there, but if I pull V2 it quiets down...

Tommy

[Bob-I]

There shouldn't be more than one ground point for all the components... but I could check. I have one bus along the pots and a small bus along the filter caps, which both connect to the chassis at the PT screw. Also there are 3 other wires connecting to that screw.

If I pull V1, the noise is still there, but if I pull V2 it quiets down...

Tommy

Move the pot bus away from the PT. Get it grounded as close to the input as possible.

[Tdale]

OK.. But the power supply grounds can still be grounded at the PT?



Tommy

[Bob-I]

OK.. But the power supply grounds can still be grounded at the PT?



Tommy

Yes, the power supply SHOULD be grounded at the PT, the rest, cathodes and signal grounds should be as close to the input as possible.