Power Questions

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Peter Etheredge

Sophomore
Jan 11, 2011
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St. Charles, IL
tnprod.com
Went on an interesting service call today. HUGE house with an expansive Crestron system (controlling a bunch of TV's, whole home SWAMP distributed audio, and HVAC) that seems to crash about once a week and need to have its power cycled to work. My predecessor had been to the site a dozen times and had gone through the coding with a fine toothed comb and all seemed to be well. At one point one of the SWAMP units had been RMA'd as have a few of the TV's. This left me wanting to check the power situation as soon as I arrived as the home is in a very rural location.

Sure enough at the wall I get a reading of 130 vac. I also get the same reading out of the Surge X (provided by the lead A/V contractor - we were just hired to program and consult on the control system) unit that the Crestron is plugged into. Looking at the spec sheet for the Surge X SurgeX - Products - SX1115R, RT, RL Surge Protector / Power Conditioners it seems that it only trips at closer to 145 vac. I'm thinking that the Crestron probably wants more stable power and for the time being had them plug it into a spare UPC they had laying around, just to see if things run smoothly this week. If that fixes it we can get a nice rack-mount UPS to cover the control system HOWEVER my question then becomes what do I do about the SWAMP amps. In any other circumstance I wouldn't even dream about using a UPS on an amplifier but would a really beefy one (or two) be my only option in a case like this? What about a voltage regulator instead FurmanSound.com - Pro A/V Product - P-2400 AR Some other type of product I'm overlooking?

Oh I should add that there are a total of two Swamp amp/control units each drawing 12 amps at 120v.
 
Re: Power Questions

What is the part that's crashing? If the crestron is crashing, can you put just that on the UPS? Also, most entry level UPSs are not very accurate in voltage regulation. They kick in at certain values, but don't guarantee a steady voltage. The higher end ones have that feature.

Power amps aren't as picky about steady voltage. They will draw more current at low voltage, and may not be able to keep up when pushed, but other than that will continue to work. Unless there are computer electronics integrated into your amps, I don't think you'd need much voltage regulation on them.
 
Re: Power Questions

There's nothing inherently bad about 130V; it's within the usual 10% voltage tolerance of 120VAC gear. Especially with anything electronic, it's going to run a transformer/rectifier and probably voltage regulator as part of the power supply...pretty much they won't care what the input voltage is, within reason. Now the stability of the 130V is the question - does it sag, does it surge... If you have a scope check out the waveform when the dryer or HVAC turn on.
 
Re: Power Questions

Peter Etheredge said:
Went on an interesting service call today. HUGE house with an expansive Crestron system (controlling a bunch of TV's, whole home SWAMP distributed audio, and HVAC) that seems to crash about once a week and need to have its power cycled to work. My predecessor had been to the site a dozen times and had gone through the coding with a fine toothed comb and all seemed to be well. At one point one of the SWAMP units had been RMA'd as have a few of the TV's. This left me wanting to check the power situation as soon as I arrived as the home is in a very rural location.

Sure enough at the wall I get a reading of 130 vac. I also get the same reading out of the Surge X (provided by the lead A/V contractor - we were just hired to program and consult on the control system) unit that the Crestron is plugged into. Looking at the spec sheet for the Surge X SurgeX - Products - SX1115R, RT, RL Surge Protector / Power Conditioners it seems that it only trips at closer to 145 vac. I'm thinking that the Crestron probably wants more stable power and for the time being had them plug it into a spare UPC they had laying around, just to see if things run smoothly this week. If that fixes it we can get a nice rack-mount UPS to cover the control system HOWEVER my question then becomes what do I do about the SWAMP amps. In any other circumstance I wouldn't even dream about using a UPS on an amplifier but would a really beefy one (or two) be my only option in a case like this? What about a voltage regulator instead FurmanSound.com - Pro A/V Product - P-2400 AR Some other type of product I'm overlooking?

Oh I should add that there are a total of two Swamp amp/control units each drawing 12 amps at 120v.
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Gear with worldwide power supplies (100-240VAC, 50-60Hz input) will be a bit more tolerant of these sorts of issues, but 130V is high enough that the homeowner should probably be talking to his local electric utility.
 
Re: Power Questions

Rob Timmerman said:
Gear with worldwide power supplies (100-240VAC, 50-60Hz input) will be a bit more tolerant of these sorts of issues, but 130V is high enough that the homeowner should probably be talking to his local electric utility.
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I maintain that a steady 130V is not causing the crashes.

And surge protectors / power conditioners / most UPS units do nothing to correct slightly high voltage.

The Furman voltage regulator would.
 
Re: Power Questions

There are computer electronics in the amps... crazy Crestron stuff. It was actually the amps that first made me think power, because they keep spitting out a voltage fault every few days.

Silas: At my suggesting the lead contractor has set the fancy expensive UPS in the network rack to log everything the power does over the next week - so that will show if it is spiking, sagging, or doing any other crazy things.
 
Re: Power Questions

Silas Pradetto said:
I maintain that a steady 130V is not causing the crashes.

And surge protectors / power conditioners / most UPS units do nothing to correct slightly high voltage.

The Furman voltage regulator would.
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What are some UPS's that would correct the high voltage. The APC unit he has the main controller temporarily plugged into now claims to do that. Does Furman make any that can? I tend to trust them above any other brand due to some past incidents where their products have saved whole systems.
 
Re: Power Questions

Peter Etheredge said:
What are some UPS's that would correct the high voltage. The APC unit he has the main controller temporarily plugged into now claims to do that. Does Furman make any that can? I tend to trust them above any other brand due to some past incidents where their products have saved whole systems.
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It would be an "online" UPS where the inverter is always running. Not cheap.

The amps logging a voltage fault may simply be because the voltage is higher than some predetermined "OK" value.

Logging the power for a week should tell you exactly what's wrong.
 
Re: Power Questions

Rob Timmerman said:
Perhaps not, but the implications of 130V very well could be. Of course, this is all speculation, and a power quality study may be in order for the original poster.
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The pole transformer might be using a higher tap than usual, maybe because that transformer is shared with another house pretty far away, or just an oversight by the power company.

Other implications might be a lose neutral or a heavy load imbalance between the two legs. Not too likely in a house, though.
 
Re: Power Questions

Peter Etheredge said:
as the home is in a very rural location.
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Definitely call the power utility. They may have set the buck/boost taps in the pole transformer years ago and have since upgraded a substation or something way upstream. They recently did that here and our whole little town was running high for a while.

I don't know what a SWAMP is (other than a type of evaporative cooler useful in southwest regions) but I've found amplifiers to complain the least about power issues and if anything don't mind higher voltages. If there is a DSP unit included in the amp then that may be a concern. Put all the "low power" devices on the UPS/regulator unit and leave the amps running off the wall. (or whatever they are on now)

The Furman voltage regulators actually work well but that would be a band-aid solution, get the power utility supply figured out first, every other electrical item in the house would appreciate it too!
 
Re: Power Questions

SWAMP is Crestron's attempt to be a one stop shop and offer zoned audio with their control stuff built into it: Product: SWAMP-24X8 - Sonnex™ Multiroom Audio System [Crestron Electronics, Inc.]

No, I'm not a fan. You can tell it was designed by programmer type people and not audio people. Really seems to be the case with any of their audio stuff IMO - it does great from a control stand point but not so hot from an audio one. So if there was a power amp that would be sensitive to wall power, this would be it.
 
Re: Power Questions

Peter Etheredge said:
You can tell it was designed by programmer type people and not audio people. Really seems to be the case with any of their audio stuff IMO
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Same with AMX, Extron and most other audio gear from companies of those sort. It's all designed from a home-audio standpoint and the audio is always of "Audiophile Quality" (-on paper at least :).
They do put DSP in them now, but what's always lacking is real parametric EQ, dynamics (limits) and even adjustable HPF's. All the things I use to keep my commercial clients happy and their systems working for years trouble free.

Pity that Sonnex amp didn't come in a direct-drive 70V version. 16ch of 250W would come in handy for some of the jobs I do!
 
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