Power cuts out when turning on DCM1540L

B

BrightSide

New Member
So I run 2 XLR-cables from my Ultra to the DCM, and four banana-plugs from the DCM to my cab(jack). Before connecting the amp to the cab I wanted to make sure the DCM was working properly so it wouldn't blow my speakers or damage something else. I have never used a power amp before, so i find it a bit scary with the DCM being quite powerful. I've read online that I would have no problem testing my SS poweramp without resistance, but the second I switch it to the "ON" position the circuit breaker activates. (It cuts the power to everything in the room.) So I turn off some other things in the room(to check if the poweramp just isn't getting enough power) and reset the circuit breaker. The same happens again. This makes me even more nervous about trying it with the cab. I tested the power cord on the Axe, but it worked just fine. I read in the manual that the DCM1540L has a 15A fuse. My power cord is 10A 250V.
Any thoughts?

This is my first post, but I've been lurking around here for quite a while. Just got my Ultra on Tuesday and I've tried it through normal speakers without a power amp. Sounds awesome so far!

Edit:
I just noticed that the cable I'm using is smaller than the one than came with the DCM (I have to use another one since I ordered it from the US and I live in Europe.)
Image of the two cables next to eachother: http://i43.tinypic.com/25z6k9s.jpg
Should i just replace the US adapter with a Norwegian one(Using the same cable)? Would that solve the problem?
 
Carvin power amps will almost always go into "protect" mode if you play through them without a speaker. It usually dosen't damage them but they will shut down. Plug everything in and just turn down the volume knobs on the front of the 1540L as well as the output of the axe. That will be quite safe. Turn it all on that way, then slowly bring up the volume.
 
Thanks!
Seems strange that it would cut the power to the whole circuit it's on if it was a deliberate protection in the carvin. My computer, fridge and everything else on this floor gets turned off. So every time I try turning it on, I have to reset the circuit breaker. The red "protect" light on the carvin does not light up because the power cuts out the second I push the on button.
I'll try with the speakers soon if what I've said seems normal.
 
What is the current rating of the circuit breaker?

> I just noticed that the cable I'm using is smaller than the one than came with the DCM

The size of the outer jacket on a power cable can be deceptive about its conductor gauge. Check the printing on the two cables and see if you can find a wire gauge (14 g, 14 AWG, 16G, something like that).

- John
 
So it's not the circuit-breaker inside the amplifier that's tripping - it's the circuit-breaker for the AC mains supply in your house? And this happens as soon as you turn on the amplifier's mains power switch?

My guess is that this is being caused by the amplifier's initial current draw, as it tries to charge its power capacitors. These power capacitors are large, and they need a good bit of energy to charge up. This can causes a brief "spike" in the current draw on the AC mains circuit in your house, and if you have a marginal circuit-breaker in the breaker-box, it can be enough to trip the breaker.

Try plugging the amplifier into a different circuit (at work, or in another part of the house) and see if the same thing happens.
 
JKos said:
What is the current rating of the circuit breaker?

> I just noticed that the cable I'm using is smaller than the one than came with the DCM

The size of the outer jacket on a power cable can be deceptive about its conductor gauge. Check the printing on the two cables and see if you can find a wire gauge (14 g, 14 AWG, 16G, something like that).

- John
Click to expand...

The circuit is 16A.
The cable that came with the carvin is 14AWGX3C while the cable i tried to use was 3G. Seems like quite a difference. The cable that came with my Axe-FX is 3X18AWG, but I'm using a 3G with it and it's working just fine. (I'm using different cables because i ordered them from the US and I live in Europe, so I can't use the ones that came with it)

xrist04: That's correct. I only trips one of the circuit breakers. And I'm using it on my most powerful circuit.
But I'll probably get a new cable that is similar to the one I got with the unit before I test it at work. It doesn't feel safe to use a smaller cable than the one it came with.

SteveB: Does carvin have a high fault percentage?

Thanks for your answers! :D
 
> It doesn't feel safe to use a smaller cable than the one it came with.

Ironically, a "larger cable" (i.e. larger conductors) will only make the initial surge problem worse. There are in-line devices which will help limit inrush currents. You only need the larger cables if you are really working the amp which I can't foresee you doing within any normal living space.

You really should take the amp somewhere else and try it out. It may well be a faulty amp since one of the features listed by Carvin is "Soft-start power-up prevents tripping AC breakers."

- John
 
Have you tried it with a different power cord?
Something else in your house must have a modular cord, try swapping cables (or swap with the axe) and see if it's a cable issue.

Have you tried it in another circuit in your house? A 16 amp breaker is not very stout, but if the wiring in your house can't handle a 20 on that circuit you might want to avoid changing breakers.

I wouldn't worry about trying it at work or anywhere else, so long as you're on a circuit with a breaker. Worst that will happen is just tripping another breaker. (Well, maybe the worst that happens is you fry the amp, but the amp has a fuse too). Since the amp is not going into protect mode and the amp's fuse is not blowing, if there's a problem, it would seem to be somehwere before the bulk of the amp's circuitry. Maybe even at the cord connection itself. When a Carvin goes into protect, the protect lights come on and you get no signal, but it doesn't turn itself off. You are just blowing the breaker in your house.

In terms of reliability, I've used Carvin stuff on and off since the 70's. It's been very reliable for me. Most repariment see it as what it is, workingman's stuff like Peavey. I've never heard about an inordinate fail rate, but bad units come out of all factories, even boutique shops.
 
So in my frustration I forgot this thread. I followed your advice and tested it at work, but there was no difference. Took it to my local music store that usually fixes my stuff, but the guy didn't even want to open it to check for loose wires. So I sent Carvin a mail explaining the problem and what I had done to test the unit. Within one hour I got a response explaining that they would replace my unit free of charge. Excellent customer service! They sent the unit the same day and it should take about 10 days (crossing the Atlantic) to get here. I'm certainly going to order from Carvin again despite them delivering one bad unit. :D
Thank you all for your great advice!
 
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