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Discussion Starter · #1 ·
I have done some searches and found much written about dealing with voltage variability but not much on consistent low voltage readings. I have tested the outlet I use for all my home theater gear and taken readings over several days and at several times. It consistently reads 115.3 volts to 115.5 volts. Other circuits in the house run in the 119-120 volt range. I know their is some tolerance in the gear for low voltage situations, but I wonder how much better performance I would get improving my voltage to 120 consistently. And if so, would it be more cost effective to have an electrician make repairs or just spring for a PS Audio or Monster AVS2000 that can correct the voltage deficiency? Any ideas?
 

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you actually mentioned what i was going to recommend,the moster solution...i believe the versions without all the digital displays and stuff are reasonable and get the job done.being in the construction trades,i think they would be cheaper than an electrician as well..


brickie
 

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I doubt that you would be able to notice any difference whatsoever between 115V and 120V at the AC receptacle.

However, the fact that it is lower than other receptacles implies that you have some IR drop in your wiring between the panel and the outlet. When your HT outlet, or other outlets on that circuit, pull higher current levels, the voltage COULD drop even lower.


Do you know what the voltage readings are with the HT equipment in use? Pinpoint other loads on the circuit, turn them on, and measure again. If your readings remain constant, I wouldn't worry about it.


Your HT gear has power supply interface circuits which are quite insensitive to the actual AC line voltage level. They could be affected by transient voltage spikes, but a constant voltage of 115V is not a problem. In fact, that is really a nominal level (lots of appliances, etc, list their AC requirements as 115V). The 110-120V incoming line voltage is essentially "chopped down" to much lower voltages before driving your amplifiers, and is conditioned and regulated before the amplifier stage as well. Most modern power supplies are quite robust to "dirty" AC power, let alone a constant voltage power line.


I would think you could run a new circuit from your panel for much less cost than a power conditioner, if you just cannot convince yourself to do nothing.
 

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Discussion Starter · #4 ·
Thanks for all the input. I tested again last night, and with appliances running and all home theater gear turned on, the home theater outlet dropped to 109 volts (other circuits in the house, normally at 119-120, dropped to 113-114 volts). Looking around at various voltage stabilizers, it looks like I could pick up a new Cinepro Powersupply II for around $350. I am guessing that is far cheaper than any solution through an electrician? Funny though, the Cinepro actually corrects voltage to a constant 117 volts rather than 120. If I had a constant 115, I guess I would be fine. Maybe my best option is to just avoid turning on any appliances while using the home theater??
 

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The problem voltages are very transient in nature. If your AC voltage simply went from 115V to 109V, but remained "clean", you wouldn't have a problem. Again, your power supplies are designed to work at all of these voltages, and will accomodate this type of drop without any degradation in performance. However, if you NOMINALLY lose 6Vac when an appliance comes on, it probably actually falls much lower for a short duration. During that time, your power supply's capacitance can supply some energy to your amp, but its energy is finite and you might notice this effect.


Even with that said, you may not notice anything at all, and I would expect that the duration of something noticeable to be much less than a second. If you continue to notice a difference the entire time an appliance is on, I would bet the effect is due to noise on the ground rather than the incoming voltage dropping to 109V.


Getting an electrician to add another circuit is probably more than $350, but really depends on how easy the access is, etc.


I have a hunch that the voltage drop effect itself is indiscernable, but it is something that will bother you unless you do something about it. Good luck!
 

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Most linear power suppies which are becomming more and more rare anyway will maintain regulation from 105-125v. Switching power supplies will typically work from 87v to 264v.


So as you can see, that 115v versus 120v isn't going to make any difference. The power supply will maintain it's output voltage in either case.
 

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I must respectfully disagree with those who think a 5-15 volt drop is meaningless. I found that I was hearing signficant grunge in from my Wadia through my electrostats at the same time that I would see the needle drop on my Monster HTS3500. I decided to pick up an AVS2000 regenerator and found that it helped the picture from my Marantz VS12S2 and the sound from my entire system.
 

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As ssabin said, it's not the consistent but lower voltage that is any problem at all -- it is rather meaningless. It's all the other things that crap up yor AC, that's what a good line conditioner can clean up (like the MP HTS3500). If you have any serious voltage peaks or drops, usually weather related, that's where a good voltage stabilizer will help (like the MP AVS2000). Of course, Monster will gladly sell you both products, whether you need both or not:)
 

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I would start by being sure all connections from the outside meter can to the main panel and on into the HT we tight and corrosion free. Tightening a loose screw would be a cheap fix.


Well tightening a loose screw is not always cheap. I was once flown from Detroit to Saudi Arabia to tighten a screw no one else had discovered was loose. Cost of service call $10K+ and a month to make all the arrangements.
 
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