Amp drops in tone/volume and then back to norm?

[Missing Link]

HI hope I am in the right place for this qestion. I have a Very nice Peavey Stereo Chorus 212. Now the problem and it is not a something that happens every time just every so often.
When playing any one of my guitars I will be playing and then the tone will change and maybe a bit of the volume with drop but not much but enough to notice and with in a few seconds it will fade back to my set sound.
I can be playing a Tele, or strat, or a LP with HB and get the same so I betting its not a guitar issue. I have changed cable and power plugs (wall) with no change. Again this in not something that happens all the time, I could go for hours and it would be normal the whole time.
I am not using the Effects loop, but I do have a P-Board with a Singular Sound Aeros and Beat Buddy, that are plugged into the front of the amp.
Any suggestions were to start or what to check when this happens?

Really appreciate any input on this and questions are welcome.


Thanks

 

[Vfc13]

Output transformer get hot?

 

[Missing Link]

Would that be HOT or real Hot? I will have to check it. I was playing on it tonight, I removed the P-Board from the front and just ran the guitar straight in front of the amp, I forgot how good it sounds just on it's own. I may have to look into maybe the P-Board maybe at fault or causing so issue? I will check the transformer tomorrow. Thanks

 

[Milspec]

My guess is bad solder joint somewhere, maybe at the tube socket or around a cap. I think Peavey had some history with that issue...they are by no means alone though.

 

[havlma1]

Bad power tube? or not clean connection between the tube and its slot

 

[Missing Link]

No tubes in this Peavey 212, will take a look at the circuit board latter.

Thanks

 

[Scuba_1978]

I am having a similar issue with a VHT Special 6 Ultra. I was going to start a new thread, but the suggestions popped this one up. I can play through either the normal or ultra input and after 10-15 minutes, the volume will get very quiet, then will come back up to normal after a short while...continuing to swell at random intervals.

I swapped input tubes, as they failed the chopstick test, only fory amp to sound great for 15-20 minutes and do it again.

Should I be focusing on solder joints, and if so, where would be the most likely places?

Thanks in advance for your help.

Edit to add...I am inexperienced with amplifier repair, but I do understand the safety principles and have worked as an electrician on and around low and high voltage. I understand how to safely work on an amp.

 

[Michael Smith]

I am having a similar issue with a VHT Special 6 Ultra. I was going to start a new thread, but the suggestions popped this one up. I can play through either the normal or ultra input and after 10-15 minutes, the volume will get very quiet, then will come back up to normal after a short while...continuing to swell at random intervals.

I swapped input tubes, as they failed the chopstick test, only fory amp to sound great for 15-20 minutes and do it again.

Should I be focusing on solder joints, and if so, where would be the most likely places?

Thanks in advance for your help.

Edit to add...I am inexperienced with amplifier repair, but I do understand the safety principles and have worked as an electrician on and around low and high voltage. I understand how to safely work on an amp.

It could be a bad solder joint anywhere, or a loose ground. Verify all of the pots and jacks are tight, transformers also. In my case it was a bad solder joint on a resistor that I couldn't see with the naked eye. Once I narrowed down the problem area, I saw it with a magnifying glass. Here's a short video I made.

 

[Scuba_1978]

Thanks, I guess there's no shortcuts for finding it then. I'll get looking

 

[Missing Link]

Practiced yesterday for three hours the amp was on all that time never got hot, and never dropped tone or sound. Today after ten minuets it did drop and come back all in about 20 seconds?
This weekend I and going to pull it apart and check the soldering and see what I can find.
Cheers
??

 

[radiocaster]

I had that problem a decade ago or something, I think the problem was the power going to the pedals.

 

[24 track]

you have an intermittent solder joint in there some where, if you are technically inclined take it to a tech, its not uncommon I see a lot of them in fender reissue amps but an inspection of the pc board may be in order

 

[Missing Link]

I will give it a good once over on the board, if that shows good I will check the the P-Boad.

Cheers

 

[radiocaster]

I will give it a good once over on the board, if that shows good I will check the the P-Boad.

Cheers

The drum machine and looper need a lot of power.

 

[Missing Link]

Last night I played the Amp without any P-Board just direct front plug-in. Not one problem and the sound with a few adjustments was clean as sweet. I am now thinking as mentioned above that maybe the P-Board is the factor causing the fade out and in problem. I reconnected the P-Board and without any peddle turned on it decreased the clean sound that I had set without the board connected, this was to include the BB and the Aeros looper. Unfortunately this amp has no send/receive but does have a power amp in and out in the back. I gave it a try to bypass the on board Reverb and Chorus, and it kind of worked or improved but not by much. Today I will still pull the brains of the amp out and take a look at the solder board.

Cheers

 

[radiocaster]

Last night I played the Amp without any P-Board just direct front plug-in. Not one problem and the sound with a few adjustments was clean as sweet. I am now thinking as mentioned above that maybe the P-Board is the factor causing the fade out and in problem. I reconnected the P-Board and without any peddle turned on it decreased the clean sound that I had set without the board connected, this was to include the BB and the Aeros looper. Unfortunately this amp has no send/receive but does have a power amp in and out in the back. I gave it a try to bypass the on board Reverb and Chorus, and it kind of worked or improved but not by much. Today I will still pull the brains of the amp out and take a look at the solder board.

Cheers

It doesn't matter if your warez fur sail (peddles) are on or not. When they are connected, they draw power. and the signal will drop if they are not true bypass. You need a power supply with more amperes.

 

[Missing Link]

radiocaster, I believe you maybe right. Yesterday a friend and I were checking the amp system out in every configuration we could do along with how it is setup normally. We found that with all the pedals set up we played for a bit and sure enough the sound started to drop and then come back. Not once but twice. Right away we disconnected the PB from the amp and it improved in sound and never dropped the vol/tone after that. So I we believe that yeas the PB power maybe to trouble we are having. The peddles are on a chain for power and just plugged into an power outlet so maybe I need to look into changing the way they get power. AS far as the amp The Peavey 212 sounds at its best without the PB connected. So now we are investigating what peddle maybe the problem and addressing the main power for all of them.
Love this amp so I feel a lot better now finding that the PB maybe the problem.

Will post on what we do for a fix in a few days.

Thanks guys
Cheers