power starvation?

[betardfoosier]

I thought I had a problem with my channel 2 on my dcm2000 power amp, but after running my pre into each channel individually, I have found both my channels are fine. But when I run both channels parallel, one into each cab, the volume fluctuates and sometimes channel two goes quiet and garbled. What could be causing this? I have eliminated cables and cabs.

[T-Bird]

Hi.

Does the protection kick in?

If it doesn't, sounds like a fault in the PS or in the protection circuit(s).

Neither is easily diagnosed or repaired, so tech time would most probably be the wisest choice.

Regards
Sam

[craig.p]

Yes, it could be power starvation. Check the usual suspects. 1) Other loads on the same breaker. 2) Extension cable insufficiently sized. 3) House voltage (off the pole transformer) is low. However, my gut feel on this one lines up with what T-Bird said, especially if this is happening at way less than the amp's max output. Call Carvin and see what they say. Could be a common fault that they'll recognize right away.

[Rick Auricchio]

If the problem happens everywhere you play, it's very unlikely that the problem is with the AC power.

Have you tried swapping cabs/channels, just to be sure that it isn't a cab causing the channel to crap out? You said "eliminated cabs." Have you therefore tried this?

[betardfoosier]

No, protection does not kick in. yes, I have tried multiple cabs and cables.the problem only manifests itself when both channels are running, but I have only run it in my friends basement, and his stack is plugged into the same breaker.

[MuzikMan]

Originally Posted by betardfoosier

No, protection does not kick in. yes, I have tried multiple cabs and cables.the problem only manifests itself when both channels are running, but I have only run it in my friends basement, and his stack is plugged into the same breaker.

Try it somewhere else and report back.

[Passinwind]

Originally Posted by betardfoosier

I thought I had a problem with my channel 2 on my dcm2000 power amp, but after running my pre into each channel individually, I have found both my channels are fine. But when I run both channels parallel, one into each cab, the volume fluctuates and sometimes channel two goes quiet and garbled. What could be causing this? I have eliminated cables and cabs.

My bet's on the parallel switch being intermittent, which I have occasionally experienced with these amps. Try a Y-cord and stereo mode instead and see if that helps.

[betardfoosier]

This sounds dumb, but I just realized I had never messed with it when my buddys guitar stack was not on. I played with it for twenty minutes tonight and it sounded great, sooooo much louder and clear.what I dont understand is why my buddys amp never sagged when mine was on?

[rpsands]

Guitars are so filthy and the actual output wattage so low I wouldn't expect it to be quite as obvious as with a bass rig. Just my guess, but I've had my amp sag when the guitar amp was unaffected before.

[T-Bird]

Hi.

Originally Posted by Passinwind

My bet's on the parallel switch being intermittent, which I have occasionally experienced with these amps. Try a Y-cord and stereo mode instead and see if that helps.

^This is also a good option. I have personally never used the supplied parallel switches on any amps, jumping the channels is much more straight forward and reliable method. IME anyway.

Originally Posted by betardfoosier

This sounds dumb, but I just realized I had never messed with it when my buddys guitar stack was not on. I played with it for twenty minutes tonight and it sounded great, sooooo much louder and clear.what I dont understand is why my buddys amp never sagged when mine was on?

What You describe is kind of impossible if the fuse(s) in your amp are as rated.

If the wall voltage drops even by 10% at "full blast", the fuses should blow (or the protection should shut down the amp) as the current demand increases. Small deviations may cause the bias to drift if there's still amps in the market where the bias circuit isn't compensated, and that will usually be audible.

I'd still suggest a trip to a tech, an amp that doesn't behave normally in every location, will more likely let the magic smoke out.

Regards
Sam