Voltage from 95 to 104v - what to do?

[camplg]

Last night I was hired for a 300 kid party. I was hired to put subs and lights.

 

 

I arrived early installed my 2 TH-118s and powered them stereo from one CP4000S. The tops used where jbl prx525s.

 

 

Did a soundcheck at full volume and everything was ok.

 

When night fell and the lights started going on I began to have some noise problems due to decreases in voltage. I pulled my kill-a-watt and the current was as low as 95 volts and as high as 104v

 

I am sure I was way under 15 amps since I only had plugged in:

 

1 EV CP4000S in stereo (not bridge) ( I was only feeding 1200W to each sub)

2 JBL PRX525

2 Led Q-spot 260

1 AmericanDJ Galaxian laser

DJ equipment which were a Denon X500, Denon D6000, traktor Kontrol S4 and 4 laptops

 

Power came from the main breaker in the house from a 10 gauge cable I built which is around 40 feet in lenght

 

 

If I had something like this would it help me?:

 

http://www.furmansound.com/product.php?div=01&id=P-2400AR

 

 

 

Thanks,

[RoadRanger]

When night fell and the lights started going on I began to have some noise problems due to decreases in voltage.

How do you know that the noise was due to low voltage?

[MJastrzebski]

 

Power came from the main breaker in the house from a 10 gauge cable I built which is around 40 feet in lenght

 

 

What do you mean by main breaker?

 

Sound like you were sharing a circuit with the outside lights.

[camplg]

 

How do you know that the noise was due to low voltage?

 

 

It happened many times, and when it did, we immediately turned down the LF on the mixer and that instantly solved the problem. Then we turned them up again until the next time it hit us. Also when we were measuring 95 volts it sounded at its worst

[camplg]

 

What do you mean by main breaker? Sound like you were sharing a circuit with the outside lights.

 

 

You are quite right. We could have been sharing with anything, but it was better than the wall outlet which we tried before.

[RoadRanger]

You might try running a separate cord for that big sub amp. If that doesn't fix it try a voltage regulator for the stuff excluding the sub amp and tops. If that doesn't work regulate the tops too. Something cheap like this would keep your low power stuff happy:

http://www.amazon.com/APC-LE600-Automatic-Voltage-Regulator/dp/B00009RA5Z/ref=sr_1_3?ie=UTF8&qid=1308413886&sr=8-3

http://www.amazon.com/APC-LE1200-Automatic-Voltage-Regulator/dp/B00009RA60/ref=acc_glance_e_ai_ps_t2_t_1

[agedhorse]

You tied a 10 gauge cable to the main breaker? Hopefully you are mis-using terminology rather than doing something dumb AND dangerous.

 

Anytime you see large voltage drops that change under load, it means that the supply wiring (could be anyplace up to and including the end of your 40' cable) is undersized for the current being drawn.

 

Voltage regulating devices are generally a bad idea because it can exaggerate the problem and when the voltage drops the reg. will step up the transform ratio and that will draw more current which will increase the supply voltage drop. The dynamics of this can lead to instability and potential failure of the regulation or the device itself.

 

The real problem needs to be fixed right.

[Crownman]

 

It happened many times, and when it did, we immediately turned down the LF on the mixer and that instantly solved the problem. Then we turned them up again until the next time it hit us. Also when we were measuring 95 volts it sounded at its worst

 

 

I had something like this happen to me once in a local club. They had just had some work done and some dumbass electrician that redid some wiring put the stage plugs on the same power leg as the A/C unit. Everytime the AC kicked on I got a bad buzz in the system and the voltage would drop to around 100 volts & lower. I tried to baby the system but the amps just weren't getting enough juice. The 2nd time the amps shut down I told the manage we needed clean power or the gig was done. He didn't like that but when I told him that the only other solution was for him to sign a peice of paper make him responsible for the cost of any gear possibly damaged he some how realized getting us clean power wasn't such a bad deal.

[Dogoth]

 

Last night I was hired for a 300 kid party. I was hired to put subs and lights. I arrived early installed my 2 TH-118s and powered them stereo from one CP4000S. The tops used where jbl prx525s. Did a soundcheck at full volume and everything was ok. When night fell and the lights started going on I began to have some noise problems due to decreases in voltage. I pulled my kill-a-watt and the current was as low as 95 volts and as high as 104v I am sure I was way under 15 amps since I only had plugged in: 1 EV CP4000S in stereo (not bridge) ( I was only feeding 1200W to each sub) 2 JBL PRX525 2 Led Q-spot 260 1 AmericanDJ Galaxian laser DJ equipment which were a Denon X500, Denon D6000, traktor Kontrol S4 and 4 laptops Power came from the main breaker in the house from a 10 gauge cable I built which is around 40 feet in lenght If I had something like this would it help me?: http://www.furmansound.com/product.php?div=01&id=P-2400AR Thanks,

 

 

Firstly the VOLTAGE was as low as 95 volts (this doesn't really tell you how much CURRENT you are drawing). At least you know the specs of the the equipment draw but..... If you see a voltage drop then somewhere in that circuit you are drawing too much load for it to handle. I would think that before you loaded it down to 95 volts a breaker would have tripped. Since it did not then my best guess would be one of two things. Either there is a high resistance point somewhere in your long supply cable or there is a malfunction with your equipment and it's causing it to draw a lot more than it's spec. If you believe your equipment is OK then it's probably the cable (Aged's intuitivness caught this right away).Too late now, but a way to check this theory would be to check the voltage across the line at the supply end of the cable vs the equipment end. If the V drop is more than a couple of % then, fix the cable (100' 10GA should be able to supply 15A without too much loss). You could try to reproduce the same thing by setting up the same system (including the cable) and CAREFULY taking the readings at the two ends of the cable. I would firstly however just inspect the cable for damage and open both ends and make sure all of your connections are tight (the smoking gun might become obvious). There could be a case where the residential supply voltage was already low (say 109V in the evening with a lot of lights on (call the power company and have them adjust the transformer taps)) and the loss in your cable exascerbated the problem. Check your cable. Next get an inductive ammeter if you really want to know what's going on. Although it's AC, it's still basicly ohms law.

 

That's my .02

[RoadRanger]

I forget what Latin American country he's in but we in the USA get a bit spoiled with having generally decent power distribution.

[agedhorse]

 

I forget what Latin American country he's in but we in the USA get a bit spoiled with having generally decent power distribution.

 

 

Same applies to spoiled food, there's not a good way to get around the potential for getting sick. You need to avoid this as well as bad power.

[camplg]

 

You tied a 10 gauge cable to the main breaker? Hopefully you are mis-using terminology rather than doing something dumb AND dangerous. Anytime you see large voltage drops that change under load, it means that the supply wiring (could be anyplace up to and including the end of your 40' cable) is undersized for the current being drawn. Voltage regulating devices are generally a bad idea because it can exaggerate the problem and when the voltage drops the reg. will step up the transform ratio and that will draw more current which will increase the supply voltage drop. The dynamics of this can lead to instability and potential failure of the regulation or the device itself. The real problem needs to be fixed right.

 

 

I think I did not misuse terminology. It was my second time doing it - so then I have been lucky I guess!!!

 

I also have a 40 feet 8 gauge cable but it has 4 cables inside of it instead of three

 

The voltage drop occurred before I was connected to the main breaker. I was plugged in to the ac before.

 

Time to call a professional electrician to teach me the ropes!!!

 

 

 

Thanks for your input!!!

[camplg]

 

I forget what Latin American country he's in but we in the USA get a bit spoiled with having generally decent power distribution.

 

 

 

I am in Caracas, Venezuela. Current is anywhere between 90 to 120 , depending on the venue.

 

I do have this item: http://www.amazon.com/APC-LE1200-Aut...e_ai_ps_t2_t_1

 

But I did not want to use it with the CP4000 amp, I figured I would trip it

 

 

Thanks!!!!

[camplg]

 

Firstly the VOLTAGE was as low as 95 volts (this doesn't really tell you how much CURRENT you are drawing). At least you know the specs of the the equipment draw but..... If you see a voltage drop then somewhere in that circuit you are drawing too much load for it to handle. I would think that before you loaded it down to 95 volts a breaker would have tripped. Since it did not then my best guess would be one of two things. Either there is a high resistance point somewhere in your long supply cable or there is a malfunction with your equipment and it's causing it to draw a lot more than it's spec. If you believe your equipment is OK then it's probably the cable (Aged's intuitivness caught this right away).Too late now, but a way to check this theory would be to check the voltage across the line at the supply end of the cable vs the equipment end. If the V drop is more than a couple of % then, fix the cable (100' 10GA should be able to supply 15A without too much loss). You could try to reproduce the same thing by setting up the same system (including the cable) and CAREFULY taking the readings at the two ends of the cable. I would firstly however just inspect the cable for damage and open both ends and make sure all of your connections are tight (the smoking gun might become obvious). There could be a case where the residential supply voltage was already low (say 109V in the evening with a lot of lights on (call the power company and have them adjust the transformer taps)) and the loss in your cable exascerbated the problem. Check your cable. Next get an inductive ammeter if you really want to know what's going on. Although it's AC, it's still basicly ohms law. That's my .02

 

 

The voltage drop was not due to my equipment, it happened when the house lights started going on when night fell.

 

Unfortunately it is not a venue, it was a private party at a house

 

My cable is around 40 feet

 

 

Thanks for your input!!!!

[agedhorse]

Your power amp could destroy the APC unit if luck went just a little bit south.

 

You do need some professional help, or no lights.

[RoadRanger]

I do have this item: http://www.amazon.com/APC-LE1200-Aut...e_ai_ps_t2_t_1 But I did not want to use it with the CP4000 amp, I figured I would trip it.

It might have worked - but as I posted earlier I'd try putting everything except the big amp and powered speakers on it first - then try it with adding the powered speakers if still having problems. Dunno what would happen if you added the amp too .

[srp72ee]

It might have worked - but as I posted earlier I'd try putting everything except the big amp and powered speakers on it first - then try it with adding the powered speakers if still having problems. Dunno what would happen if you added the amp too .

 

Here again there are a lot of unknown variables... "Might have" is a bit optimistic. That APC unit doesn't like large varying loads (such as a power amp), it was primarily ment for computers or other small scale electronics. The CD players and other electronics pull a faily constant load, so the APC can regulate moderately well just needing to compensate for incoming line variances.

 

If the line voltage is dropping that much with loading, something is getting warm somewhere...

[Mutha Goose]

As a general rule of thumb and 1st order check, if your power extention cords are getting warm, they are under-sized (IR loss). If they don't warm up too much, the power problem is not due to the load of your equipement that is plugged into that extension cord but somewhere else (supply, loading in a different leg, etc.).

[RoadRanger]

As a general rule of thumb and 1st order check, if your power extention cords are getting warm, they are under-sized (IR loss).

If his 10 gauge unfused tap is heating up it's time to head for the hills .

 

[agedhorse]

It might have worked - but as I posted earlier I'd try putting everything except the big amp and powered speakers on it first - then try it with adding the powered speakers if still having problems. Dunno what would happen if you added the amp too .

 

That's just plain bad advice IMO.

 

Might have worked (unlikely at best) but could have destroyed the amp and the APC (the most important part).

[camplg]

 

As a general rule of thumb and 1st order check, if your power extention cords are getting warm, they are under-sized (IR loss). If they don't warm up too much, the power problem is not due to the load of your equipement that is plugged into that extension cord but somewhere else (supply, loading in a different leg, etc.).

 

 

Thanks, I did check this many times and my 10 gauge cable did not even get slightly warm

 

The 16 gauge I used before did get warm, but with this one no problem

 

On the 10 gauge were:

2 PRX 525

1 EV CP4000S amp in stereo at 4 Ohms

2 Led moving heads

4 laptops, a Denon X500 mixer, a Kontrol S4 and a denon D6000

[RoadRanger]

Dunno what the surge rating is on them type of regulators. Mine is an old Sola 1000w ferroresonant that has no surge rating at all - it is inherently current limiting so NG for amps. Too big and heavy to carry around regularly though .

[agedhorse]

CV transformers are a different beast entirely, though there are limits due to core saturation and inadequate LC capabilities beyond the design load.

 

When you make off the cuff recommendations, you need to be sure to qualify with real, accurate information. Folks reading these threads will take away bad advice and then go and damage things. That's not a very charitable thing to do IMO.

[RoadRanger]

That APC is protected against overload by a circuit breaker and his amp is no more likely to blow up from the APC than from the poor power without it. OTOH he'd want a second, bigger regulator to feed that amp proper. I suspect the "noise" is from the tops or driving electronics and not from the sub amp anyways so running everything except the sub amp from the APC (as was my recommendation for something to try) is worth a try. I suppose your recommendation is for him to get himself a USA grade power plant and distribution network to run off of? I suspect that is a little out of his price range .

[agedhorse]

That APC is protected against overload by a circuit breaker and his amp is no more likely to blow up from the APC than from the poor power without it. OTOH he'd want a second, bigger regulator to feed that amp proper. I suspect the "noise" is from the tops or driving electronics and not from the sub amp anyways so running everything except the sub amp from the APC (as was my recommendation for something to try) is worth a try. I suppose your recommendation is for him to get himself a USA grade power plant and distribution network to run off of? I suspect that is a little out of his price range .

 

Your experience is so far from mine (and reality) that I have to wonder. Protection may or may not work, may not work reliably with reactive loads, may not work at all with resonant or dynamic loads.

 

My recommendation was to identify the cause of the problem and fix the problem. That's the smart and safe solution, I am not into giving recommendations for bad solutions or dangerous solutions. You seem to like taking the seat of the pants approach which more often than not leads to a bad outcome. I hope you don't drive your rig like that.