Single Rectifier Hum, UPDATED-Now Im getting somewhere-HELP!

[slayer44]

Ive got the worst hum (as in, not a normal "I can deal with it" hum - a very, well Transform-ery sound) coming from my Single Rectifier. I dont notice a volume drop when I switch to channel 2 and the tone seems to be ok. The clean channel has a slight hum, but nothing major. Channel two is the problem, Ive never heard an amp hum like this before. I know we have many tech saavy guys lurking on the board, so give me some advice if you can. Ive found other threads, and have tried the suggestions with no results. Here is what Ive done sor far:

Completely Retubed the amp
Tried a few different outlets
Ran a 5150 in the same outlets with no problems
Changed speaker cable
Turned everything off in the garage, no lights/ac
Changed the power cable
Took all effects off and ran guitar>amp
Used an iSP decimator in front and a Boss Noise Supressor in the loop with absolutely no noise reduction at all even with both pedals dimed.

Any help would be appreciated. Thanks ahead of time.

 

[Jak0lantern01]

Bad resistor? Cap? Is it making noise without the instrument plugged in? Does it make noise when in standby?

 

[slayer44]

When the instrument is plugged in yes. Standby, no.

 

[richey]

What kind of pups are you using? Does it do it with more than one guitar?

 

[Jak0lantern01]

What about with the guitar unplugged and no cables running to the amp? If there's no hum in that situation, then it's either the cable or guitar's wiring/jack.

 

[slayer44]

Ive tried a duncan equipped guitar and a EMG equipped guitar. It does it with no guitar connected, and with no cable in the input jack. I think Ive tried just about everything, it must be internal.

 

[Platypus]

When you replaced the preamp tubes, did you use new tubes?

edit: and not to second guess you, you replaced all 7 tubes in your amp?

 

[Jak0lantern01]

I just replaced my pre-amps, it helped. Also, the new ones are replacing a whole other new set, they were causing the hum. Be careful where you buy tubes from, there's a decent amount of hype around here regarding some dealers who have a very narrow view as to what tubes sound good. My experience wasn't so good and it cost me.

 

[Jak0lantern01]

I just replaced my pre-amps, it helped. Also, the new ones are replacing a whole other new set, they were causing the hum. Be careful where you buy tubes from, there's a decent amount of hype around here regarding some dealers who have a very narrow view as to what tubes sound good. My experience wasn't so good and it cost me.

 

[slayer44]

Yes, I replaced all 7 tubes. One completely new set, and another slightly used set, as well as the stock tubes. Looking more and more like major issues.

 

[Platypus]

Bummer

 

[Jak0lantern01]

Could be a resistor going bad. I'd hate to recommend ordering a whole new set of tubes, did you try replacing pre-amp tubes one by one? I had a very similar issue that was resolved by replacing an already new set of tubes, as I stated earlier. The hum was really disturbing me, so I felt forced to order yet another set of new tubes, this time from a different vendor (Doug's). Sent me a really nice combo and the amp sounds great and has no hum. By the way, does it hum in both channels?

 

[slayer44]

Switching one by one was the first thing I tried before throwing a completely new set in. This may be a stupid question, but do you think the Rectifier could react differently to the household electrical system, as opposed to the 5150? Do you think a furman power conditioner can solve the problem?

 

[AliensExist4]

slayer44: I'm having similar problems but with my 2ch. Trip. Rect. It hums pretty loud even with my guitar hooked up and the volume off.

- Patrick

 

[slayer44]

The Furman power conditioner did nothing.

Although, I think it may be a bad input jack. Will any input jack work, or is there a certain type I should look for? The amp doesnt make any noise without the cable in the input jack, and the hum sort of swirls if i move the cable while in the input.

 

[clutch71]

The Furman power conditioner did nothing.

Although, I think it may be a bad input jack. Will any input jack work, or is there a certain type I should look for? The amp doesnt make any noise without the cable in the input jack, and the hum sort of swirls if i move the cable while in the input.

Sounds like it may be time to have it looked at my a Mesa tech. Can't hurt. Under warranty?

 

[slayer44]

Yeah, Ill have to make the call on monday. Thanks for the help, I guess its out of my hands.

 

[slayer44]

Ok, this is where Im at with this problem. I took out the chassis and I removed the input jack from the amp. I plugged in the cable (while the input jack was hanging out of the chassis), and the amp sounded perfect. Now when I bolt the input jack back into the chassis, the hum comes back. So, I cant keep the input jack hanging, anyone have any ideas to solve this? Maybe Im answering my own question, but does than mean I have a bad input or a bad ground?

 

[frankencat]

Maybe somehow try and shield the input a little better. Or it could be a ground issue.