Question AVR Power Specs - What does 2 Channel Drive Mean

Discussion in 'AV Receivers & Amplifiers' started by nheather, Jun 27, 2015.

  1. nheather

    nheather
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    Looking at a Marantz AVR and the specifications list this against power

    number of poweramps 5
    Power Output (8 ohm, 20 Hz - 20 kHz, 0.08% 2ch Drive) 50 W
    Power Output (6 ohm, 1 kHz, 0.7% 2ch Drive) 60 W
    Power Output (6 ohm, 1 kHz, 1% 1ch Drive) 85 W

    What does 2ch drive mean. Is that stereo? If so why would you specify a 5.1. AVR as stereo.

    And also if it is stereo then what is 1ch drive?

    And does it mean that this amp could not be used with 4 ohm speakers.

    Cheers,

    Nigel
     
  2. dante01

    dante01
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    It indicates the power the receiver can provide while driving only two speakers with an impedance of 8ohm. The receiver would have a lower rating per channel while driving more speakers simultaneously. One channel driven should be ignored and is simply a way for the manufacturers to make the power rating look better. There's no situation where you'd ordinarilly only use one channel of amplification, but this would result in more powr being available. The fewer channels amplified then the more power per channel is available.

    This isn't an indication that a receiver shouldn't be used with speakers other than those with a nominal impedance of 8ohm and simply gives the power in relation to speakers with an impedance of 8ohm. Speakers with an impedance of 4ohm would result in a different higher rated power output from the receiver. You''d ordinarilly have confirmation as to whether or not a receiver can deal with lower impedance speakers on the rear of the receiver or within its manual.
     
    Last edited: Jun 27, 2015
  3. nheather

    nheather
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    Thought so, just seemed weird, the 1 channel especially so.

    But even the 2 channel is odd - it is a 5.1 AVR, if I wanted a stereo amp then I would buy a stereo amp.

    So I'm left totally in the dark about what this 5.1 AVR can do.

    It's a Marantz NR1504/1605.

    The manual doesn't provide any more insight.

    Cheers,

    Nigel
     
  4. dante01

    dante01
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    Yeah, getting the manufacturers to actually tell the truth and give a rating for all channels driven is like getting blood from a stone. You can guesstimate the power available for each channel by dividing the power consumption by the number of channels, although this is by no means an accurate way of calculating the power rating.

    Using the above would indicate that the NR1504 has about 40 watts per channel at its disposal while the 1605 has about 45 watts. Realistically, 30 - 40 watts.

    What speakers will you be using and what is the room's volume/size?
     
    Last edited: Jun 27, 2015
  5. nheather

    nheather
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    Only small stuff - Wharfdale DX-1.

    The room is fairly big 5m x 5m but the TV and viewing position is confined to one corner.

    Cheers,

    Nigel
     

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