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Class D Amp Cutting out on stage, Not at home when testing

#41
The GK MB's have something they call "Smart Protection Circuitry". Here is what the manual says:

"Smart Protection Circuitry: The MB Series protection circuitry constantly monitors for unsafe operating conditions such as short circuits, miswired speaker cables, blown speakers, improper ventilation, and incorrect speaker configurations. In addition, protection is provided during power up/down. If the MB Series senses any unsafe operating conditions, the output signal is immediately muted and the power light changes from Blue to Red. The amplifier will remain muted until the fault is removed. Be sure that you are not exceeding the maximum recommend load described in this manual. If the problem persists, contact GK directly for technical advice."
 
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#42
I was present when that issue happened to a keyboard player I was working with

We were playing a very old yacht club and the electric was terrible

I had for years run all of my gear through a furman conditioner in a rack I had and never had any issues. I often wondered if it actually did anything other than be a glorified power strip

The keyboard player who had all digital gear finally plugged into my power strip and everything returned to normal

I eventually sold the rack and went with a class D amp but bought one of the Furman line conditioner power strips and have never had any issues

Maybe you can try that

I learned first hand that even though it looked like it was doing nothing ... it actually was keeping the voltage consistent and digital gear needs that kind of TLC

Just a thought my friend.
 
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#44
agedhorse said:
Fortunately breakers don't half-way trip or they would only provide half-way protection.

Voltage drop is a different thing entirely, and it's possible that what the OP is experiencing is due to this. As a note, this can occur to non-class D amps as well, some amps (including a couple of my lead sled designs) do include low AC voltage protection so that the amp is protected when the voltage gets dangerously low. In many class D amps, this protection is present because some bad things can happen when the supply voltage falls, different from a traditional linear amp.
Click to expand...

The only breakers that could possibly do that are old Federal Pacific. Well, they just never trip...
 
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#45
I had an issue with my old GK 400RB. If I would play loudly/aggressively it would cut out. I narrowed the issue down to the input jack. Tried cleaning it, tried tightening up the contacts, and tried different cables to no avail.
I was pretty sure the jack was bad, but before I changed it I just reflowed the solder points on the board. Voila! No more cutting out. Must have been a bad joint.

However, that's probably not your issue, I just wanted to regale you with my GK story... Good luck, bring backups.
 
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#46
Jewce said:
Dude, I was going to sell my 5 string the other day. As I was cleaning it up and playing it one last time, my volume cut about in half. Then back on again. Then out. Then I hit the bass, and it kicked on again. I figure it's a shirt in the preamp, so I called off the sale until I get it fixed. But, I'm thinking you might have a similar wiring problem.
Click to expand...

i had that very problem years ago with my first bass. it didn't cut out often, but every so often it would, and whacking the front of the bass would bring the sound back. the preamp didn't wear a shirt, though...

:D
 
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#47
chris_b said:
So the common factor for the problem seems to be the amp, and the NO power supply. If his amp is sensitive to power issues the you might have hit on the problem.

Can you try a different amp through your cabs?
Click to expand...

I would not agree it may be the power supply, IME. OP states that the problem does not occur in all venues, but occurs in more than one venue. In a place with notoriously bad power supplies. So, the fact that it DOESN'T do it at some venues would suggest at least the possibility that it IS power-related since, theoretically, if it's the amp or cab, it should do it everywhere. (Caveat: unless it's a loose wire short that sometimes makes contact and sometimes grounds out.) I am no amp doctor, but I lean towards loose wire, or bad power supply, based on the symptoms.
 
#48
I once had a Behringer Ultrabass head that would cut out at gigs but I could never reproduce it at home or practice. I started looking for other factors and realized it was really hot gigs. Took it out and played it in the garage with no AC for a while and there was the problem. It was a badly ventilated design. I drilled a couple of 1.5" holes in the chassis with a hole saw and it never cut out again. I guess they didn't have Texas heat in mind when they designed it.

The shady power situation that has been discussed much is also a likely suspect.
 
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#49
My uneducated guess looks like...seems like a low voltage at the wall thing to me. Low voltage, lower rails, super early onset of clipping, protection then shutdown. Modern amps with protection circuits are probably more likely to do this than some older amps where you may just sound like crap but your amp will ride it out.
 
#50
papasolly said:
...I’ll check it with different speakers and probably bring my solid state too as a back up in case it is in fact the amp...
Click to expand...
So, this implies you Class D amp is one of those extremely rare all tube models, eh?

Jewce said:
...I figure it's a shirt in the preamp..
Click to expand...
Button-down or pullover? They can create different types of issues.................

mustBmtd said:
...Might try microphoning your cabinet.
Click to expand...
How would this help?

johnson79 said:
The only breakers that could possibly do that are old Federal Pacific. Well, they just never trip...
Click to expand...
One of the first things we did when we moved in to our house was get rid of those and upgrade the electrical service.
 
#53
One of the first things we did when we moved in to our house was get rid of those and upgrade the electrical service.[/QUOTE]

Most, if not all insurers require them to be changed out prior to moving into a new home. They really are as bad as the stories tell. It happened to me while I was installing a light. Flipped the breaker on and heard some noise, turns out the hot conductor insulation got cut and it was burning a hole through the mounting plate...
 
#55
jhfishn said:
I was present when that issue happened to a keyboard player I was working with

We were playing a very old yacht club and the electric was terrible

I had for years run all of my gear through a furman conditioner in a rack I had and never had any issues. I often wondered if it actually did anything other than be a glorified power strip

The keyboard player who had all digital gear finally plugged into my power strip and everything returned to normal

I eventually sold the rack and went with a class D amp but bought one of the Furman line conditioner power strips and have never had any issues

Maybe you can try that

I learned first hand that even though it looked like it was doing nothing ... it actually was keeping the voltage consistent and digital gear needs that kind of TLC

Just a thought my friend.
Click to expand...
lets not start with the snakeoil power conditioner waste of money suggestions..
gosh i wish these would just disappear.
 
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#56
/\/\3phist0 said:
lets not start with the snakeoil power conditioner waste of money suggestions..
gosh i wish these would just disappear.
Click to expand...

You sir are the reason folks resist trying to help others out

This actually worked and the Korg keyboard stabilized and worked flawlessly after that

I really thought over before posting a reply to the original Op since I figured someone would tear it up .... sure enough ... here you are
 
#57
SOMETIMES, a bit of spike protection helps, primarily with digital equipment where a small amount of high amplitude noise can corrupt data, but when folks attribute low voltage correction to a device that can't possibly (by design) do ANYTHING to correct to low voltage, that's where the snake oil enters the picture.

IMO, it becomes worse when the marketing perpetuates, or promises something that is not possible.
 
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#58
You can buy a simple voltage meter for just a few bucks online.
Those "watt meters" include voltage and current
If your gear cuts out on low voltage and the venues you play have shady voltage then you should address that.
I have experienced just the opposite where my amp works and other people's amps cut out - and it was because if was a shared circuit with a freezer that dropped the voltage. The answer to tell the venue to provide clean power. Put it in the contract. Separate circuits, X Amperage - if you're worth it they'll at least check it.
 
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