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Denon 3803 into 4ohm speakers

Discussion in 'Home Cinema Speakers' started by Dodgey, Dec 15, 2003.

  1. Dodgey

    Dodgey
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    I'm looking at getting a 4ohm speaker setup (Kef reference) which will be driven by my 3803 (Denon) - I'm advised this may be a bad choice for me. I guess the 4ohm load will be half as efficient as 8 ohm?

    I thought my Denon had plenty of power to spare?
     
  2. davehk

    davehk
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    The 3803 PSU has limited current capability - it cannot drive all its channels to 110W at the same time - it's actually only capable of about 40W RMS continuous per channel into 8 ohms all channels driven (look at the maximum AC power consumption - it's about 350W!)

    Using 4 ohm speakers put a heavier current demand on the PSU for a given power output (P=I^2*R, so if you halve R you need SQRT(2) times the current for the same power).

    So likely with 4 ohm speakers it will only do 20W RMS Continous all channels driven at the same distortion level!

    Of course, the instantaneous power capability is a different matter, as the low continous current capability of the PSU can be mitigated by large reservoir capacitors to cover the transient load. (no-one ever said audio was simple!)
     
  3. Jase

    Jase
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    I wouldn't run the 3803 with Kef Reference speakers. The minimum Denon you should run those with would be the A11SR or ideally the A1SR. Others would only consider running those speakers with dedicated power amps. :)
     
  4. Dimmy

    Dimmy
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    Good Guess Dave HK.

    The AVR3803 delivers 50wpc into 8 ohms with five channels driven (never mind seven...), and into 4 Ohms this collapses to 25 Watts with a massive 3.4% THD if I remember correctly.

    This is one receiver you definitely SHOULDN'T use with 4 Ohm Loads.

    Marantz, Harmon Kardan and perhaps Yamaha or Pioneer would have an easier time driving such speakers, Harmon Kardon in particular, whose amplification seems to have masses of current.

    Dimmy
     
  5. Dodgey

    Dodgey
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    Thanks guys. A non-issue now. Went for a demo and got carried away. Now the owner of:

    Mirage OM-7s x 2
    Mirage OM C2 x 1
    Mirage OM R2 x 3
    B&W ASW750

    :)
     

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