Volume Inconsistency on 5150 Combo

Hey Everyone,
I am playing a Les Paul Studio thru a Peavey 5150 2x12 combo, and I'm getting fluctuations in the volume while I'm playing. It will sound normal at first, then within a few minutes, it will get much quieter for awhile, then come back to normal again in a bit. What could be causing this? I'm not sure if it's my amp or maybe the output jack on my guitar, or possibly even my pickups... Does this occur if your tubes are going bad or something? Any advice would be greatly appreciated. Thanks!
_MRBUNGLE_

the same kinda thing happens to me on my Crate GFX 212. if i screw around with the fuses on the back it cures it for a while. i dunno maybe its just something with 2x12 amps. good luck

hm...
i think i get the same. Im not shure if i understand compleatlig.

The sound is changing without u do anything with the knobs? cuz that happends to me sometimes on clean tone (with metal zone on) I have a peavy envoy 110..

My Gallien-Kreuger Backline 100 transistor amp does that too, and I haven't been able to sort out why! My Ampeg tube amps, and my Peavey Rock Master tube preamps are fine. My transistor amp makes me crazy, because when it works right, it does have a really good sound to it. The tech at the local dealership is under a 4-month backlog, so I haven't brought it in. Then again, if I'm not using it, it might as well sit in the shop.

Ok, Does it do this every time you use the amp and does it do this on both channels, I'm not real familar with the 5150, it has reverb right, does it do this if the reverb is on 0 ?.................

Yeah, it happens without me doing anything -- as for the other questions -- it does happen on both channels, but I haven't tried turning the reverb to 0 yet. Is there something about reverb that may cause this? It's just weird, because it will be fine for maybe 10 or 20 minutes, then go quiet for about a minute, then come back again... strange.... but I guess i'm not the only one w/ this prob!

Thanks to all for the replies, BTW!

_MRBUNGLE_

If I am understanding you correctly, and your amp is dropping in volume,fading off and coming back, but not totally going silent, I believe you could have a power tube going bad, as time goes on it will probaly happen more often with greater effect, the tube is dying off slowly and might just drop dead at any moment, best bet is to get it to a shop as soon as possible, keep the best matched pair of tubes for a back up set, get a good quad and get the bias set and you probaly won't believe how good your amp sounds...........

btw, I'm not saying it couldn't be something else, but this is probaly the most likely and about as good a diagnosis as you'll get on the net.....

I've never let a set of tubes get to that point, but I'm inclined to agree with pstring. Even if this is not what's causing the problem, a visit to your local tech is more likely to clear it up than trying to troubleshoot it over the net. This kind of thing needs hands-on examination.

P.S. I'm taking my G-K in for service. Now that I think about it, I'm annoyed at not having it available for use. Its not my first-choice amp, (not while I have 2 Ampeg tube amps to choose from!), but its kind of stupid to have gear collecting dust because "it needs a little work". :rolleyes:

[Edited by Lordathestrings on 08-05-2002 at 12:32 PM]

Thanks everyone, you've been a big help. I know it's hard to say what the problem could be without physically having the amp in front of you, so I appreciate you all trying. I'd have to figure that pstring is right as well. Looks like a trip to the shop is in order!

Maybe I'll make the best of it and put some nice Sovteks in there... ;p

_MRBUNGLE_

Getting 60 Watts out of a pair of 6L6's means pushing them hard. A pair of 7027A's would drop right in, and should be bulletproof in your amp. My 1977 Ampeg VT-40, (measured 70 Watts rms @ 5% distortion), is still running strong on the original tubes! The 7027A is readily available, and since they aren't as well known (popular) as the 6L6, they actually cost less.

Thanks again -- I will take that into consideration!