Receiver Amperage

Discussion in 'AV Receivers' started by Russell Osborne, Jul 6, 2003.

  1. Russell Osborne

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    Hi,
    I was hoping someone could tell me what current my Yamaha RXV 630 puts out . I noticed that H/K lists theirs on their website but I can't find anything on Yammies . Thanks for your help.
     
  2. Wayne A. Pflughaupt

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    Not sure I get the question, Russell. Receivers (and other ampfliers) consume (or draw) amperage, they do not put it out.

    Regards,
    Wayne A. Pflughaupt
     
  3. Kevin. W

    Kevin. W Screenwriter

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    I think he value that H/K list is the total amperage devices for all channels. You could try e-mailing Yamaha.

    Kevin
     
  4. RobWil

    RobWil Supporting Actor

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  5. Russell Osborne

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    OK . Perhaps my nomenclature is incorrect. What I would like to know is the high instantaneous current capability of the rxv 630.
     
  6. Jason.Soko

    Jason.Soko Stunt Coordinator

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    Ummmm last I checked Wayne current drives the speakers. How could it put out NO current?
     
  7. Yogi

    Yogi Screenwriter

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    Let me take a stab at it. I am not sure if this analysis is right but if it isn't then I'd appreciate if someone would correct me.

    Here it goes. Look behind the receiver for total watts consumed by the receiver. Divide that number by the number of channels on it. This will give you the total watts consumed per channel. Now the total watts consumed per channel is not the total watts output by that channel as there are dispersive losses and as no amplifier is 100% efficient. A good rule of thumb is that Class B amps (which are used in allmost all the receivers) are only about 75% efficient. So neglecting all the other losses and the preamp consumption multiply that number by 75%. This will give you the true RMS output per channel (no matter what the spec sheet tells you). Now assuming the speaker is a constant 8 ohm impedance (as the current required will change with impedance), divide the output per channel number that you have with 8 and take the square root of it. This will give you the RMS current per channel that this amp can put out per channel.

    So for example the HK 7200 consumes 1040 W at rated output into all seven channels. So it gives out 1040/7 * 75% = 111W/ch RMS of all channels were going simultaneously. Now into 8 ohm load it would put out Sqrt(111/8)= 3.72 Amps continuously per channel. This I think is the true output capability of the 7200 no matter what the spec sheet says. Peak to peak, +/- a certain amps etc etc are just marketing mumbo jumbo. BTW 3.7 amps continuously per channel is quite high current. You'd be surprised to find not many receivers can do that. So [​IMG] to HK7200.

    My 2 cents.
     
  8. Jason.Soko

    Jason.Soko Stunt Coordinator

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    Yogi you can't just calculate it that way. You have to see how much voltage the receiver actually puts out. There is a difference between high current 70w and low current 70w. That is why there are $10,000 amplifiers that put out far less wattage then $200 amps. Wattage means really nothing. There is 2 ways to get to watts, increase voltage or increase amperage. 10volt output at 10amps is 100w, 100volt output at 1amp is 100w. Know what I mean?
     
  9. PhilMays

    PhilMays Stunt Coordinator

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    At Yamaha's web site they say 75 watts per channel with a maximum of 110 watts per channel.

    Hope that helps as you went through alot of "junk" to get to what I think you were asking.
     
  10. Dimme

    Dimme Extra

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    PhilMays, that's not what he's asking.

    I do know that the Yamaha x40 series, like 540/640/740 have an Amperage of about 34 Amperes . The Pioneer VSX-811rds about 31 Amperes
    The 630 is less than that, should be around 30, maybe a little less since Yamaha designed the new x40 line of receivers with an especially high current power supply.

    Hope this helps
     
  11. Michael R Price

    Michael R Price Screenwriter

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    What the heck does "receiver amperage" mean? Remember, the speakers have a nearly constant impedance and that defines the relationship between voltage, current and power. And if you can find me an amplifier that delivers 30 amps into a speaker, I'll take it! Heck, it doesn't even have to be a real speaker. Do you have any idea how absurd that number is?
     
  12. Russell Osborne

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    Thanks to all for your replies . I believe Dimme got the gist of my question though I truly appreciate all input as I am relatively new to HT . Wasn't my intent to start a war here though [​IMG]
     
  13. Dimme

    Dimme Extra

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    Michael R Price, you are pretty wrong in saying that a speaker has a nearly constant impedance, the impedance varies depending on the frequency you are playing.
    If you have ever used a Marantz amplifier with a true power level meter, you know what is said when a receiver needs a nice power supply that can give high current.
     
  14. Yogi

    Yogi Screenwriter

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    30 amps RMS into any speaker impedance is absurd. 30 amps peak OTOH is something else.
     
  15. Jason.Soko

    Jason.Soko Stunt Coordinator

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    Ummm and how the hell are you getting 30amps from anything? People need to realize you don't use nearly a fraction of the max power something can use. Just because an amplifier can suck down 16 amps doesn't mean you are EVER even going to come close to that. I saw an amperage reading at a local stereo shop with some really high end shit, Mcintosh etc. running some hometheater speakers. With everything running and pretty damn loud, it was barely using 4-5 amps. My moon I-5 draws 9 continous with a possibilty of 16 max. 30 is beyond obscene.
     
  16. Dimme

    Dimme Extra

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    Yogi, it's 34 amps total in the x40 line and not just in ONE speaker. This amount of current is needed when playing at high volumes and using big speakers or speakers that have a low sensitivity.
    Remember though that you have losses, too in forms of heat and resistances in the electronic design of the receiver.

    So that total of 34 Amps that the power supply can give is in fact less than it can actually totally deliver to the 6 or 7 different speakers that are connected to it.
     
  17. Michael R Price

    Michael R Price Screenwriter

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    I meant the speaker's impedance is fairly constant with respect to the input voltage. Of course it does vary with frequency. Sure you need a nice power supply, but these peak current numbers I'm hearing have nothing to do with power supply strength. They seem pulled out of the blue. 34 amps would be about enough current to supply an output stage to 200 watts continuous into 4 ohms in 5 channels at once. There's a reason why we don't see any receivers that can do that, eh?
     
  18. Jason.Soko

    Jason.Soko Stunt Coordinator

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    I'd really like to see someone hit 30amps in a hometheatre, lol. People get so carried away with these speakers require 110watts but my amp/rec only does 60. Like you will even come close to playing 110 watts in a channel.
     
  19. Dimme

    Dimme Extra

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  20. RobWil

    RobWil Supporting Actor

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    Harman Kardon likes to advertise their 'HCC' or 'High Instantaneous Current Capability' ratings in their specs. This is supposedly beneficial during peak passages in a musical reproduction and is supposedly indicative of the quality of the power supply.
    Examples are their AVR 7200 with an HCC od +/- 75 amps, AVR 525 HCC +/- 45 amps, AVR 325 HCC +/-35 amps, etc.
     

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