Possible 5150 Issue?

[yarrick19]

I picked up a used 5150 not too long ago and love it. When I've used it recently I've noticed that after I play for 30 minutes or so it gets louder all the sudden. Then after a few minutes the volume will drop a bit. It randomly does this. Volume changes arn't huge, but noticable (and a real drag when recording!!!). Is this a power amp tube going out or something? :zombie: Anyone have any ideas?

Thanks

 

[Mark_Palangio]

Try taking some contact cleaner and spraying it in the effect loop jacks, then taking a cord and plug it in and out a few times. If that doesn't work, it's probably a tube issue.

 

[Splat88]

Sounds familiar. Peavey jacks go bad quickly. Like Mark said, take a chord and plug it in and out of all the jacks. You can actually even tap the jacks hard with your fingernail. I used to have to do that in the middle of concerts. It sucked.

 

[Mark_Palangio]

Sounds familiar. Peavey jacks go bad quickly. Like Mark said, take a chord and plug it in and out of all the jacks. You can actually even tap the jacks hard with your fingernail. I used to have to do that in the middle of concerts. It sucked.

I used to have to take a cable and have it plugged into both jacks to get any volume, but that problem just went away. Weird.

 

[kaomao]

Power tubes!
Change 'em

 

[Gnash]

Yeah, I used to have to do the same thing. Right in the middle of a take, it drops out, you have to reach up and tap on the effects loop jack. Wouldn't work live, because of the cabinet vibarations. You could have bad jacks man.

 

[yarrick19]

Thanks for the input everyone. I'll mess w/ all the jacks when I get off work tonight - Hopefully its nothing major.

 

[yarrick19]

I tried the contact cleaner in the jacks and that didn't seem to have any affect on the volume changes. I ordered new power tubes (JJ) and although they are much smoother sounding that the stock sovtecks, I still have the same volume changing issues. :-(

Last night I was experimenting while i was playing and found that if I wiggled around the preamp tubes and pushed them in slightly my volume would increase. After a bit the volume would drop back down (the change isn't instant when going from loud to quieter - its more like a 2 second fade) and I could wiggle and push the preamp tubes and it would get loud again.

Could a bad pre amp tube cause this? Or is it more likely something loose up there near the preamp tubes?

 

[006]

Sounds like your socket. I would take it to a shop ASAP.

~006

 

[yarrick19]

What is the socket? (What is its functional purpose?)
(Or are you talking about the socket that the tube plugs into???)

 

[cobhc]

What is the socket? (What is its functional purpose?)
(Or are you talking about the socket that the tube plugs into???)

i'm sure he means the socket for the tube.

 

[atoni]

Hi! I have 5150II, and I'm facing same kind of issues with it. Volume drops and comes back again time to time.

yarrick19 what was the reason for problem and how was it solved.

Does anybody else have experienced same kind of issues with 5150 or 5150II? Could you share how it was fixed..?

Thanks!

 

[yarrick19]

Atoni,

It actually turned out to be something wrong w/ a preamp tube...

I first tried replacing the power tubes and the problem persisted. I spoke w/ the guys at Eurotubes (great guy!) and said that preamp tubes could also cause this kind of behavior. So, got a new set of preamp tubes (from Eurotubes of course), pulled the old tubes out, cleaned the sockets w/ some contact cleaner, installed the new tubes and no more problem!

I dug up my email converstion:

Hello,

I got my power amp tubes - thanks for the fast delivery! The reason I purchased them was because the volume on my Peavey 5150 has started changing while I am playing. For example, randomly it will get louder and then it will go back to where the volume was initially, then louder, etc. I figured this was a power tube issue but unfortunately the new tubes didn't seem to fix it.

Any ideas on this one? I noticed that you recommend retentioning the sockets on your website and I havn't had a chance to do that. Could this be a possible fix?


REPLY:


Volume level fluctuations can also be caused by preamp tubes. Since the problem existed prior to the retube, it is likely not a loose socket issue but I would recommend cleaning the sockets since only the slightest bit of oxidization can cause an intermittent connection on a single pin. Otherwise it's the preamp tubes or a completely non-tube related issue, possibly an intermittent cable.

It's easy to clean the tube sockets which can be done by removing the tubes and then using one of them, spray the pins with some electrical contact cleaner ( you can even get this at a Radio Shack, they call it TV tuner cleaner ) and then work the tube in and out of each socket a few times to remove dirt and corrosion. If no contact cleaner is available then simply working the tube in and out of the socket a few times will usually suffice.

If this does not cure the problem you can troubleshoot and replace the preamp tubes one by one, and if it’s a tube issue you will soon find it.

Thanks

-Jay



Hope that helps!

 

[atoni]

Thanks man! I really appreciate it.

Time to haul the amp to the tech...

EDIT: I bought a JJ ECC83S sextet and replaced all Sovtek preamp tubes. I also cleaned the tube sockets with that "contact cleaner with old tube" method. Turned the amp on and WOW!! Everything worked great, all odd noises disappeared and the sound man.... I'm enlightened, and from now on I will only use JJ's

No need to go the tech...yet

 

[yarrick19]

Glad this worked for you as well!

 

[Loren Littlejohn]

Just take it to a tech, it really makes life simpler especially if the tech knows what he is doing.

 

[Torniojaws]

I thought it was a known issue with stock 5150/6505 preamp tubes. They only work for a while before dying with issues just like yours. Replacing them with proper preamp tubes fixes it.