Ampeg Micro VR Strange Problem

BulbousMoses · #1 10-04-2011, 01:27 PM

Ok so I've discovered a strange problem with my Ampeg Micro VR. When I turn the gain knob, the amp makes a scratchy "dirty pot" type of noise. As a little experiment, I zeroed all the other control knobs on the amp and fiddled with the gain knob again...no noise. Then, I tried putting one knob (didn't matter which one) at 12 o'clock. Still, the gain knob makes no noise when I turn it. After a few iterations, I was able to discover that the gain knob will only make this sound when all the other knobs are engaged to some degree. Anyone else have this problem and if so, anyone know why it would do this?

BulbousMoses · #2 10-05-2011, 06:57 AM

Bump...Jimmy? Anyone?

JimmyM · #3 10-05-2011, 07:28 AM

Hmmm...I'd assume a dirty pot but I'm no tech. If you have any Deoxit laying around, you could try pulling out the head and spraying the pot. Don't use just any contact cleaner on it, though...some of them can ruin the pot. If that doesn't work, call Ampeg.

beans-on-toast · #4 10-05-2011, 07:43 AM

As Jimmy said, try deoxit first to see if the pot is the source of the problem.

If that doesn't fix it, one possibility is that there is a DC offset on the pot. This could cause a scratchy sound. Perhaps there is a leaky capacitor in the signal path or a short somewhere. A tech would have to examine it.

BulbousMoses · #5 10-05-2011, 07:59 AM

It just seems strange to me that it only makes this noise with all the other controls activiated. Like I said, if I turn every knob to zero, I can spin the gain control all day long with no scratchiness..

JimmyM · #6 10-05-2011, 08:07 AM

Well yeah...you're not putting out any volume so naturally you wouldn't hear it

BulbousMoses · #7 10-05-2011, 08:10 AM

Quote:

Originally Posted by JimmyM

Well yeah...you're not putting out any volume so naturally you wouldn't hear it

Opps...right you are. Anyway, just got off the phone with the place I bought it and they just happen to also be an authorized Ampeg service center so I'm going to drop it off tomorrow.

**TRichardsbass** · #8 10-05-2011, 08:37 AM

Well, Jimmy is the Ampeg guy, but Fenderhutz here has had problems with his Micro VR, so it could be related. Reach out to him as well.

tom

BulbousMoses · #9 10-05-2011, 08:41 AM

Quote:

Originally Posted by TRichardsbass

Well, Jimmy is the Ampeg guy, but Fenderhutz here has had problems with his Micro VR, so it could be related. Reach out to him as well.

tom

Thanks, Tom. I'm pretty sure it's just a dirty pot (although the head is only 6 months old and never gigged so how it gets dirty in that amount of time is a mystery). Anyway, I'm taking it to the service center tomorrow and I'll see what they say. It's all under warranty.

Timmah · #10 10-05-2011, 08:49 AM

I had the same prob, deoxit works.

JimmyM · #11 10-05-2011, 08:56 AM

Quote:

Originally Posted by TRichardsbass

Well, Jimmy is the Ampeg guy, but Fenderhutz here has had problems with his Micro VR, so it could be related. Reach out to him as well.

tom

Nope, not related. The other problem was a bizarre reaction some of us were having to using two 210av's with the Micro VR that only happens with that particular combination of cabs and no other. This just sounds like a dirty pot.

BulbousMoses · #12 10-05-2011, 09:25 AM

Quote:

Originally Posted by JimmyM

Nope, not related. The other problem was a bizarre reaction some of us were having to using two 210av's with the Micro VR that only happens with that particular combination of cabs and no other. This just sounds like a dirty pot.

How is your Micro VR and 2 cab setup sounding these days? Are you still having the clipping issues a la Hutz?

JimmyM · #13 10-05-2011, 09:39 AM

Well there is a fix Ampeg can do for it, but I haven't done it because I've got a PF350 that I use with them now, and Ampeg was nice enough to invite me to be an endorser, and I don't want to be a schnorrer when the PF350 works great.

BulbousMoses · #14 10-05-2011, 09:44 AM

Quote:

Originally Posted by JimmyM

Well there is a fix Ampeg can do for it, but I haven't done it because I've got a PF350 that I use with them now, and Ampeg was nice enough to invite me to be an endorser, and I don't want to be a schnorrer when the PF350 works great.

Fair enough. I'll have to go back and re-read hutz's thread. I can't remember offhand if playing style had any effect on the clipping. I play with a light touch with low action. I'd like to pick up a second cab.

JimmyM · #15 10-05-2011, 10:26 AM

Quote:

Originally Posted by BulbousMoses

Fair enough. I'll have to go back and re-read hutz's thread. I can't remember offhand if playing style had any effect on the clipping. I play with a light touch with low action. I'd like to pick up a second cab.

Then it may not affect you. Playing style does affect it. Owen Biddle used to use two 210av's with a Micro VR on the Jimmy Fallon show and I never heard his rig do that. But if it does, they have a fix for it so you won't be up a creek without a paddle in any event.

fenderhutz · #16 10-05-2011, 10:30 AM

*lurking*

Ampeg actually swapped out my entire rig for something else. Because the "fix" wasn't satisfactory to me. They took care of a customer, and I am grateful for that. I no longer have a Micro VR rig.