Mystery continues

[Gibbyage]

So Ive been having problems with this two channel rectifier I got from a trade off the board.

I installed all new tubes. Bought different cables. And I even bought a new cab (wanted a 2X12) and the head still makes this weird crackling noise!

I play with the master volume (effects loop) maxed and then I adjust my channel volume from there.

If I get to a loud volume such as maybe a un-mic'd live sound it starts doing it. Mind you it does it worse when head is on cab.

But if I back off the effects loop output to 1 o'clock and then adjust to channel volume from there it doesnt do it. (head off cab still)

I just bought a Stiletto deuce and this head nor my 5150 does it.

I need more ideas as to what it is. Wiring?

 

[JOEY B.]

Try turning the knob on the rear to "Bypass Loop". Then ease up the channel volumes to try and re-create this problem. If you're lucky, the problem will be isolated to the FX loop circuit. It's then just a matter of using the process of elimination. Good luck.

 

[nomad100hd]

Something is loose, a pot maybe something else. Kind of gave it away "it gets worse sitting on the cab." might even be a bad pot, does any of the pots feel loose?

 

[Charles Reeder]

Hey:

I had the same problem awhile back with a Lonestar Classic.

Mind you there are plenty of other 'possible' causes...but my LSC was doing it because the effects loop jacks were dirty. I sprayed some contact cleaner on the male jack of a 1/4-inch guitar cord...and worked it in-and out of the effects loop jacks for a little while. I gave the contact cleaner some time to evaporate and tried out the amp. I have not had the 'static/crackle' problem since.

This may not be the problem with your amp...but it's worth a try...it certainly won't hurt anything.

Charles

 

[Gibbyage]

Hey:

I had the same problem awhile back with a Lonestar Classic.

Mind you there are plenty of other 'possible' causes...but my LSC was doing it because the effects loop jacks were dirty. I sprayed some contact cleaner on the male jack of a 1/4-inch guitar cord...and worked it in-and out of the effects loop jacks for a little while. I gave the contact cleaner some time to evaporate and tried out the amp. I have not had the 'static/crackle' problem since.

This may not be the problem with your amp...but it's worth a try...it certainly won't hurt anything.

Charles

I didnt have any effects going at the time when it was making the noise.

One member on the board said I should open the cab and put this tape against the sound post and it should isolate it.

I'm gonna do that tomorrow.

I didnt notice any pots being lose but I'll check.

 

[jdurso]

wait did i read that right... output maxed as in all the way up?? :shock:

what kind of practice space are you playing that bad boy in because there is loud (output at 1 oclock) and deafening (output all the way)? are you using an attenuator?

 

[Gibbyage]

HA. I always read and see people saying that they play at 11 or noon with their channel volume.

But I usually have the loop output maxed and then adjust my channel volume to around 11 o'clock or whatever is loud enough.

But If I back off the output on the loop to around 1 o'clock and then adjust the channel volume is wont do that noise (sometimes it comes through)

But I bypassed the loop and tried to recreate the noise with just the channel volume and I got to around 1 oclock and it just had more of a screeching noise (didn't have my noise suppressor hooked up) and only once or twice did the crackling noise.

One of the pot screws was loose and I tightened that up. But thats about it.

 

[Gibbyage]

I did what one member suggested and that was put foam on the sound post and i cant really tell if it made a difference yet since its getting late. I'll post tomorrow with results.

 

[JOEY B.]

A crackling sound that is set off by vibration is most likely a poor connection somewhere. Like someone else said, it could be at the jacks, tube sockets,or a faulty pot. One of my amps had a loose ground braid on the bass pot that gave the same symptoms when vibations got high.

I would clean all the jacks and the pots with contact cleaner, for starters 8) .

One thing that I don't understand is the "max" setting on the output when you are not running anything through the loop. It seems that this would just add preamp noise because it then passes the signal through the V4 preamp tube. Bypassing the loop should eliminate the send and return jacks and V4 as possible sources, if the crackling still occurs.

 

[domct203]

Mesa's are capable of incredible amounts of gain in all stages. Using the FX Loop with nothing in the loop is just another gain stage. With the loop levels maxed, you are most likely amplifying noise in the amp that wouldn't normally be heard.

Try setting the loop a little more conservative and make up the volume with your channel masters and output. This will help to keep the preamp signal level above the noise level (AKA noise floor) in the preamp.

Dom

 

[MikeK]

... for what it's worth ... I ran into a something similar with a Twin. Crackling and squealing intermittently, sometimes blowing a fuse. What it turned out to be was a bad tube socket on one of the 6L6's. Looking at the socket from inside the chassis, a couple of the pins were loose enough to wiggle. I imagine a cracked solder joint might do the same thing.

 

[NoGlassNoClass]

"Worse on the cab" obviously a vibration problem as suggested above. Yes, could be loose tube sockets, bad solder joints, dirt, pots just about anything. Dont overlook the obvious...speaker cable.

 

[Gibbyage]

I bought a new speaker cable trying to eliminate little things that might be wrong.

I run a lot of effects through the loop but when I jam by myself I dont run anything in the loop.

How do I go about using the contact cleaner? is that just for jacks or can it be used for the pots also?

I'm thinking its just a bad pot now. One of the power tubes wiggles more than all the rest.

 

[Gibbyage]

Since the sound is still coming through and my last thing is a bad pot... where might the bad pot be most likely?

And how much do they usually cost to fix.

 

[cellardweller]

How do I go about using the contact cleaner? is that just for jacks or can it be used for the pots also?

As previously posted, just spray some electrical contact cleaner on a male 1/4 inch plug and work it in and out (plug and unplug).

Do look out for the stuff that they call "tuner cleaner", as the one I bought contains some type of lubricant (castor oil?) that can make everything a slickery mess!!!

 

[Gibbyage]

How do I go about using the contact cleaner? is that just for jacks or can it be used for the pots also?

As previously posted, just spray some electrical contact cleaner on a male 1/4 inch plug and work it in and out (plug and unplug).

Do look out for the stuff that they call "tuner cleaner", as the one I bought contains some type of lubricant (castor oil?) that can make everything a slickery mess!!!

Thanks.

And how much do repairs usually run for fixing pots?

 

[jdurso]

HA. I always read and see people saying that they play at 11 or noon with their channel volume.

But I usually have the loop output maxed and then adjust my channel volume to around 11 o'clock or whatever is loud enough.

But If I back off the output on the loop to around 1 o'clock and then adjust the channel volume is wont do that noise (sometimes it comes through)

But I bypassed the loop and tried to recreate the noise with just the channel volume and I got to around 1 oclock and it just had more of a screeching noise (didn't have my noise suppressor hooked up) and only once or twice did the crackling noise.

One of the pot screws was loose and I tightened that up. But thats about it.

oh you meant the output of the fx loop not the Output of the amp? I thought you meant the big black Output knob on the front of the amp. That maxed out would been extremely loud.

 

[Gibbyage]

So how much am I looking at if I take it to the Hollywood Mesa shop?

 

[nemesys]

You'll have to pay for bench time, of course, but I wouldn't guess that it would be too expensive, depending on what's wrong with the amp -- as others have said, it could be a few different things -- a bad pot, bad tube socket that is arcing, an intermittent solder joint, even as simple as a bad tube. The good news is that none of those parts are expensive at all.

Good luck getting it fixed.

 

[Gibbyage]

You'll have to pay for bench time, of course, but I wouldn't guess that it would be too expensive, depending on what's wrong with the amp -- as others have said, it could be a few different things -- a bad pot, bad tube socket that is arcing, an intermittent solder joint, even as simple as a bad tube. The good news is that none of those parts are expensive at all.

Good luck getting it fixed.

If one of the tubes is still bad I'll **** myself after all the money I spent on tubes lol.