Hello everyone. I recently bought a new Carvin bx700 and a 2x10 cab off their website. The amp worked flawlessly until maybe three months after purchasing it. If I play a note on my bass, the amp distorts like crazy, like a square wave sound. At first, I thought the lone 12ax7 had gone bad, so I replaced it. It solved nothing. And the distortion only happens when the tube is engaged (it has a tube bypass button). I called Carvin but they really sucked at getting me through to their amp tech. I'm pretty pissed off. Any advice would be appreciated.
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Carvin amp problems
- Thread starter el guitarronista
- Start date
Call Carvin back, they are your repair source and you'll probably just be exchanging for a new unit. Be nice and patient.
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Have you tried the effects loop trick, where you connect a small cable between the Send and Return ? Sometimes these jacks get dirt and crap in them, and could short out the signal. There is also the ribbon cable issue which pops up now and then on some Carvin heads. This is a little bit more involved fix, and I'll let the more knowledgeable, who have done this fix, to tell you how to do it.
A lot of Carvin amp problems just end up being loose/dirty ribbon cable connections inside. Cheap, easy, basic cleaning/maintenance type of fix.
That said, it's new. You have a warranty, so use it.
Call them and tell them your problem. They'll likely have you send it back and they'll probably just send you another amp.
Likely cost you shipping.
Get up on basic De-Oxit connector cleaning for a couple years from now when it's not in warranty anymore.
That said, it's new. You have a warranty, so use it.
Call them and tell them your problem. They'll likely have you send it back and they'll probably just send you another amp.
Likely cost you shipping.
Get up on basic De-Oxit connector cleaning for a couple years from now when it's not in warranty anymore.
I haven't tried that... I didn't even know you could solve the problem like that lol. I shall try that right now. Thank you.
I read about that ribbon cable on another Carvin thread. How would you clean the cable though? Just rub it all over the cable?
What is the HV step up power supply? Sorry if I'm asking a beginner question, I'm not familiar with technical things like that.
The normal output module DC voltage supply goes through a DC multiplier to bring the say 80 volts the output uses to the 150 to 250 volts the tubes plates need. Low plate voltage will cause any tube to run highly distorted. You did say the amp sounds okay when you bypass the tube.
Yessir, it sounds completely normal when I bypass the tube. Also, the distortion happens when I tap the top of the head.
Also, the distortion happens when I tap the top of the head.[/QUOTE]
Clean and reconnect the ribbon cable. That should do it. I had the same problem with my BX500 the first week of use (bought it new).
Clean and reconnect the ribbon cable. That should do it. I had the same problem with my BX500 the first week of use (bought it new).
I always thought that the Carvin ribbon cable problems documented here were a load of baloney. I had two Carvin amps with problems, A DCM1000 that became intermittent on channel two after a fall in its SKB case, and a BX1500 that the Tuner out, and thus the effects send, did not work from new. Cleaning the ribbon cable connectors fixed both amps problems. I still don't think that this is something limited to Carvin amps. Many manufacturers use similar architecture in their amps.
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I too have had the ribbon cable issue with my Carvin Power Amps (DCM2000L and DCM3000L). Disconnecting the ribbon cables, cleaning the connectors (with a cleaner/lube that I got at Radio Shack) and reinstalling fixed the issue.
--jack
My BX500 just had the ribbon connector problem. It worked fine at a gig a couple months ago, but when I tested it last weekend before heading to a gig, there was almost no sound. I opened it up, pulled the ribbon connectors on the circuit boards, cleaned them with a squirt of Deoxit, and reconnected them...back in business now. But I couldn't figure out how to get at the connectors on the front panel. Anybody done that?
Apparently the front panel connectors are notoriously difficult to clean, and basically no one does it until it becomes a last resort... I haven't done it yet on my BX500.
Ive gigged my DCM2000L for 3 years and all the while thought that their power amps did not have that idiotic ribbon cable bullsh*t design.If mine does in fact have that stupid design feature I'll figure out what to do with the hulk if intermittent operation plagues me. What a damn disappointment to learn that I chose an power amp with such a lame design feature - my fault. However, this power amp has great features, sounds very clean and is serving me well so far. And I really like the fact that it's a USA made product. I live 10 miles from the factory and I'll give them ... heck if my amp falls to such a dumb symptom. They may just shrug me off.
- Mar 8, 2011
- 12,232
- 51,187
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- Authorized greenboy designs builder/Owner of BNA Audio
I recently bought a (used) DCM 2000L that is having some weird problems...gonna crack it open, clean it up and see if that does the trick 
+1
Those ribbon cables can make Carvin amps do goofy stuff, from introducing static into the signal to putting the unit into protect mode. If you have a Carvin amp, it's a good idea to pop it open every six months or so and reseat the ribbon cables.
I can maintain my dcm2000l power amp with regard to the ribbon cables but I'd rather not. What other power amp has similar power without ribbon cables?
Thanks.
Thanks.
