Household voltage question

Discussion in 'Home Theater Projects' started by Kevin. W, Apr 5, 2004.

  1. Kevin. W

    Kevin. W Screenwriter

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    Just curious what is classified as too low for your household voltage. I just got a Monster HTS5000mkII and the dial read 115-118v. Would that be classified as normal?

    Kevin
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    Yep.

    AC power to your house is classified/rated to run a 220v, 3-phase motor. I believe the voltage is allowed to drift something like 10-12%. So 'normal' range for a 110 outlet would be 99-121 volts. (Any electrical contractors in the house?)

    Most of the power supplies in your electronics are designed to handle these voltage ranges. But using a power conditioner does help.

    Are you seeing any difference in the video? (I pick on video because your eyes are usually more sensitive than your ears.)
     
  3. Jon_Gregory

    Jon_Gregory Stunt Coordinator

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    Electrical engineer here. You are in the normal range for a typical household outlet. Outlets can vary by a certain amount as stated above. Usually things can handle anything in the 95V to 120V range. There are some appliances that will not like being on a lower voltage such as 95V for an extended period of time, but most outlets do not drop that low unless the wiring is degraded or other problems occur. But your readings are within the normal range.
     
  4. Kha:T

    Kha:T Agent

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    Well, I just got a Monster Cable line conditioner as well. It's the MP-HTS5100. The voltage readout on my unit also displays between 115v and 118v. I have yet to see it go outside of that range.

    I was going to create another thread for my following question, but since we have this thread here already, I hope you guys won't accuse me of thread hijacking.

    [​IMG]


    Kevin W, do you have the power plug of your subwoofer hooked up to your HTS5000mkII? If you do, do you always get a nasty turn-on thump from your subwoofer everytime you turn on your receiver after an extended standby mode?

    For some strange reasons, I get exactly that. It's not only annoying and startling (very loud) everytime, but I also fear that something in the sub will break soon.

    I tried to get an answer from Monster Cable as it doesn't do that if I plug my receiver and subwoofer into another cheapo MC surge protector. All I got was that MC is aware of that phenomenon and that I should contact the manufacturers of the sub and the receiver.[​IMG] I was like, "this can't be for real..." but I was getting nowhere with whomever I talked with at MC.

    I first suspected that the lack of proper grounding on the electrical outlet contributed to the problem. I then fixed the receptacle and it has a proper ground now, but the problem still persists.

    So does anyone have any suggestion or advice as to how I can get rid of that awful turn-on thump?

    Thanks in advance.
     
  5. Allan Jayne

    Allan Jayne Cinematographer

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    If you turn on the subwoofer system after the main amp has been on for a few seconds, is the problem alleviated?

    As far as I know, normal voltage is 110 to 120 volts. 105 to 109 and 121 to 125 are still considered acceptable. Below 105 is considered a brownout. In some rural areas voltage may fluctuate and go up to around 130 and it is necessary to purchase light bulbs and appliances designed for 130 volts.

    In many areas, what is expected to be 220 to 240 volts is about 208 volts and normal while the accompanying "110 to 120" volts is indeed 110 to 120. It is then necessary to be sure that "240 volt" appliances purchased are intended to run on 208 volts.

    Many appliances have (all should have) published lower and upper voltage tolerances. On average, the lower the voltage, the more watts (as well as the more amperes) an appliance will draw. Appliances have been known to overheat and burn out in brownout conditions as well as overspeed/overheat and burn out in overvoltage conditions.

    WHen audio equipment is first turned on, a hum can find its way all the way to the speakers until the filter capacitors (whose purpose is to smooth out the 60 Hz or more commonly 120 Hz ripples from more efficient full wave rectification yielding a smooth DC power supply) charge up. Usually a "muting" or delay circuit is in the amp. to silence the speakers until the power supply so stabilizes.

    In addition the power draw for the first second after turn on can be somewhat more than the normal maximum draw during loud passages. A good amp. needs a lot of "juice" to fil its filter capacitors. This has nothing to do with high or low or normal line voltage. This in turn can make the thump heard from the speakers louder than you might guess and could cause damage. If you have a surge protector that softens this thump, most likely that particular surge protector won't pass the initial power draw in amperes although it should itself not burn out in the process. Except you don't want a surge protector that causes the voltage feeding the amp to fluctuate as the amp plays loud and soft passages as this will distort the sound.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  6. Kevin. W

    Kevin. W Screenwriter

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    If the back of your 5100 is like mine I'm pretty sure there isn't a plug marked for the sub. Try plugging the sub into the wall socket and not the 5100 and see what happens. I don't get the thump with my amp(Paradigm PW2100). What amp do you have?


    One thing I also noticed is late at night the dial will read 120v. That gives me the impression that my household voltage is affected by whats going on outside my house?
    Kevin
     
  7. Kha:T

    Kha:T Agent

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    Kevin, there's no "subwoofer" outlet on my HTS5100 - or any other Monster Cable power center for the matter as I've checked them all out at a local Tweeter store. I actually plugged it in the "spare" outlet and set a switched delay (20 sec) on it.

    Anyway, since this turn-on thump has driven me nuts, I decided to do some experiment last night. I originally had the receiver (Onkyo TX-DS797) plugged into the "receiver" outlet and the sub (Earthquake Supernova mkIV 10) into the "spare" outlet. That setup gave me nasty turn-on thumps. Then I left the receiver alone, but pulled the sub from the power center and plugged it into a Panamax 500 DBS. I still got turn-on thumps. Next, I reverse the two plugs, the sub into the power center and the receiver into the Panamax. Turn-on thumps still exist but at a much subdued level. Looks like the receiver is the culprit.

    Or is it?
     
  8. Kevin. W

    Kevin. W Screenwriter

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    Try plugging the sub into the wall socket and see what happens. Also what is the volume setting on the sub? It could be too high. I don't think its the receivers fault, if anything its the sub drawing the power.

    Kevin
     
  9. Cary_H

    Cary_H Second Unit

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    My Paradigm PS1000 has an indicator light that comes on when it sees a signal. I have noticed that when I plug a second appliance in the outlet my sub uses the field induced wakes up my sub. Any chance your sub is powered up when it ought not to be and gets a bump from the startup of your system?
    How about temporarily plugging it into an outlet on a different circuit and isolate it's signal cable to the receiver the best you can from all other cabling to see if that doesn't fix things. My bet is it's not directly power related and won't occur if you disconnect the signal cable. If your sub was off it wouldn't matter, but it sounds like it's 'always on' and something is coming down the line to it.
    I get the same thing from my PC's speakers when I bootup my PC. They are 'ON' 24/7 and pop regardless of their volume setting. It toasted my fronts in short order.
     
  10. Kha:T

    Kha:T Agent

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    Thanks to everyone who has given me inputs and suggestions.

    I finally found out why I got those turn-on thumps after pulling out and plugging in those power cables hundreds of times.

    Since I had to buy another power center, I decided to get the HTS-2600 so I could test out everything. When I plugged the Earthquake sub to the HTS-2600 and another Onkyo receiver (Integra model TX-SV838), there was no turn-on thump. When I used a second sub (a Mirage BPS150i) and hooked it up to the Onkyo DS797 and the HTS-5100, turn-on thumps were popping left and right. I then plugged the Mirage sub and SV838 back in the HTS-2600, there was no thump. So the culprit was the DS797 receiver. For some reason, it will send a voltage spike to the sub, which results in very very loud turn-on thumps, if I let it sit in standby mode for an extended period of time. When I continously turn it on and off, the thumps are not as loud.

    So as any perfectionist audio nut would do, I decided to replace the TX-DS797 with a TX-NR900.

    Now everything's quiet when turned on like how it's supposed to be. [​IMG]
     

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