Nasty Static from my Amp (Sounds like an old AM Radio)

[BAN]

So, I've had this problem develop recently with my amp. It started very infrequently, and now it's there every time I turn on the amp.

The best way for me to describe it is that it sounds like an old radio when you're turning the dial from one station to another. That kid of deep, scratchy static (as opposed to, say, the higher pitch white noise of a TV with no signal).

It happens with the amp volume all the way down and nothing plugged into the amp at all. Flip standby off and there it is---intermittently coming through the speaker and definitely loud enough to make playing an irritation. Oh, and it doesn't increase in volume when the volume is turned up---it stays at the same level.

I've tried swapping out preamp tubes but no luck there.

Any thoughts?
BAN

[Phil M]

I would've thought preamp tubes.

Since you tried that, try your power tubes (less likely).

Barring that, it might be time for a cap job. When you run your hand over the top of your amp, does it make any difference in the static?

[BAN]

Thanks, Phil.

No, no difference no matter what my proximity is to the amp (hand over the top does nothing). Oh, and it's a fairly brand new boutique amp with excellent components, so I'm assuming no cap job needed.

BAN

[Jason_86_951]

Does this amp have an effects loop? If so, try (with the amp off) pluging a cable in and out a few dozen times in the send and return. Sometimes they get dirty and can cause the exact thing your talking about.

Give it a shot.

[BAN]

Ugh. No effects loop.

It's a one-input, single-channel 6L6 amp with nothing else other than reverb. Oh, and it's a 1x12 combo. Pretty basic in almost every way (except the glorious tone. when there's no static.)

[Phil M]

Sure sounds like a tube issue to me. Maybe re-check all the preamp tubes just to be sure.

Speaker connection?

And last but not least, have you ruled out that the problem could be coming from a specific guitar or cable? (not calling you dumb, I just know I've been that dumb before!)

[BAN]

I'll check all the preamp tubes again. And the speaker connection.

It's definitely not coming from the guitar or a cable since it happens with nothing at all plugged into the input----i.e., just the amp turned on and the volume all the way down.

[Sherman]

I was messing around w/my amp this weekend and heard the same thing. Checked the speaker cable/connections and they were fine. Then I remembered that I had some old 12AX7 pulls in the preamp section. I replaced each one with a newer tube and by the end of my tinkering the noise was gone. I think your issue is your preamp tubes.

[Phil M]

I was messing around w/my amp this weekend and heard the same thing. Checked the speaker cable/connections and they were fine. Then I remembered that I had some old 12AX7 pulls in the preamp section. I replaced each one with a newer tube and by the end of my tinkering the noise was gone. I think your issue is your preamp tubes.

I've experienced this before too. Once it turned out to be an intermittent short in the cable, but usually it's 12AX7s that are either not seated right or are shot.

[ronin32]

I had the same sounds coming from my Blues Jr. and I bought a new 12AX7 tube that sounded bad, put the new tube in and it still made the sound. I ended up switching all the tubes around and it hasent made the sound in a couple of weeks.