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Problem with QSC GX5

#21
agedhorse said:
I do not recommend using power amps with "power conditioners". Power amps (such as the GX-5) already have all the necessary protection built in.
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I agree with you on this and even if I didn't understand the reasons (and I actually do), would still take your advice as a the subject matter expert in both design and live pro-sound/touring use.

I do have ask though, if you're going to be in a situation where power is known to be bad (we often face this with local power at deployed military sites), isn't that a time to look into something like we use that is a combination UPS and power conditioner? For the record these aren't one or two space rack strips, they are not cheap, and not exactly small or light. The ones I recall would literally take power that was virtually unusable frp incandescent lighting and provide an uninterruptale output that was clean enough for lab and automatic test equipment.

I have no idea what the state of play is comercially for these devices, but assume they would not be practical for most musicians...maybe touring folks?? On the other hand, if the power will be that bad, a good generator might be the easiest, cheapest, and safest solution.
 
#22
byacey said:
Most panel breakers will easily handle the inrush current during the split second that the caps charge. I agree that there is most likely other loads on the same circuit pulling considerable current that is already heating the circuit breaker. I don't know what a typical branch circuit breaker rating is at 220 volt, but I doubt its more than 8 or 10 amps.
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In residential, I think 13A is the limit for general purpose receptacles.
 
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#24
What else is plugged in on that circuit? If turning the amp in always trips a circuit breaker, take it to a plug on a different circuit and try it there. One way to find a different circuit would be to turn off the one that always trips, and go find some other plug in the building that has power and try the amp there. If that works, the circuit you’re plugging into likely already has near its limit of current being drawn. A space heater/etc might be enough to cause that. If it trips the second breaker though, I would strongly suspect something is wrong with the amp.
 
#25
Are you using standard Schuko (type F) grounded receptacles? If so, and this is an older building that may have been converted from type C receptacles, beware that the overcurrent device could be as low as 2.5A which would certainly cause an issue.
 
#26
agedhorse said:
In residential, I think 13A is the limit for general purpose receptacles.
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13a @ 220V is a lot of power available at a residential receptacle.
Years ago I knew a technician that had escaped from Slovakia when it was still under the communist regime. He told me a story once about working on a Russian made television set from the 1970s; when initially powered on, the streetlights out in front of the building dimmed noticeably, and that's when it was working normally!
 
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#27
byacey said:
13a @ 220V is a lot of power available at a residential receptacle.
Years ago I knew a technician that had escaped from Slovakia when it was still under the communist regime. He told me a story once about working on a Russian made television set from the 1970s; when initially powered on, the streetlights out in front of the building dimmed noticeably, and that's when it was working normally!
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I thought I had some interesting USSR Cold War stories, but that one is simply a Wow!
 
#31
byacey said:
At 220V, the inrush current should only be about half of what it is at 120V, so I'm curious why it would be tripping a panel breaker, if there isn't any other significant loads on the circuit.
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This is not my usual swim lane, but I have experienced unusual problelms with breakers that became "overly sensitive" to certain loads when they reached the end of their useful service life. A new breaker in the panel and everything was fine again for any connected load (that was within spec).
 
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#32
Al Kraft said:
This is not my usual swim lane, but I have experienced unusual problelms with breakers that became "overly sensitive" to certain loads when they reached the end of their useful service life. A new breaker in the panel and everything was fine again for any connected load (that was within spec).
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I've seen instances of weak breakers too, although other loads would likely cause it to trip as well.
 
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#33
As far as I know the standard in Germany for breakers is 10 or 16A. I doubt that is the problem.
In certain older ( pre ‘73) buildings in Germany you can still find zero grounding (I have no idea what the proper english term would be) the zero fase is connected to ground. Maybe this is a cause for the amp shorting the breaker?
 
#34
I had a similar problem with an Ampeg B2 combo. When I switched it on the circuit breaker of 16A tript (there was also a freezer connected to this group). The fuse on the amp stayed intact (5A, slow).

My house is from 2017 and the circuit breaker is not an old fashioned one but a new type (fast).

I found the schematics of this amp and saw there was a modification done to this amp in 1997 while my amp is from 1995. The mod was an extra NTC to limit the inrush current. The B2 has a toroidal transformer.

I was able to fix my B2 with an extra NTC just like the official mod.

I am not saying your amp has the same problem and you must install a NTC, but it's worth checking.
 
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#35
The problem almost certainly has nothing to do with the grounding.

If the circuit has other loads, that is the most likely cause, or if the breaker is weak/defective.

Otherwise we should wait to hear from Bob Lee.
 
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#37
I’m not too clear regarding the specific OP issue; so, will be interesting how Bob Lee might respond.

I use a QSC PLX1804 powered through a Furman PL Tuner rack strip. The one thing about that arrangement is to never use the power strip to turn on the power amp. I always have the power amp switched off when powering up the rack, and then switch the power amp on when the rack power has settled. Reverse for power down.

If the external circuits can’t support the power amp, then there is little you can do to correct that issue, short of powering from a high quality separate generator. As previously stated, that’s an electrician issue, not an amp issue. And a power strip can’t make up for it.

FWIW
 
#38
TonH said:
I had a similar problem with an Ampeg B2 combo. When I switched it on the circuit breaker of 16A tript (there was also a freezer connected to this group). The fuse on the amp stayed intact (5A, slow).

My house is from 2017 and the circuit breaker is not an old fashioned one but a new type (fast).

I found the schematics of this amp and saw there was a modification done to this amp in 1997 while my amp is from 1995. The mod was an extra NTC to limit the inrush current. The B2 has a toroidal transformer.

I was able to fix my B2 with an extra NTC just like the official mod.

I am not saying your amp has the same problem and you must install a NTC, but it's worth checking.
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I ended up doing that, a limiter is being buit into the amp. I think definitely the problem is in the power of building, but since there is little I can do about it I decided to modify the amp with the extra NTC.
 
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#39
Sorry, I didn't see this thread until today.

I'm not sure of the OP's problem, but it seems to be that the amp won't turn on and instead always trips a circuit breaker--is that correct? If so, then the amp needs servicing because there is something seriously wrong with it. What country are you in?
 
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