H/K receiver and speaker impedance

Discussion in 'Archived Threads 2001-2004' started by Mike*Gillgannon, Nov 24, 2002.

  1. Mike*Gillgannon

    Mike*Gillgannon Auditioning

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    The rather confusing manual for the H/K AVR225 doesn't have anything to say about speaker impedance -- at least not that I could find -- but on the back panel the speaker terminals are marked "8 ohms." My mains (PSB Stratus Minis) are rated at 4 ohms. Everything sounds fine, but is a nominal 4 ohms impedance likely to stress this amp over the long haul?

    --Mike
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    It largely depends upon how loud you play your system, and if you depend on the L/R speakers to handle the low-frequency sounds.

    Suggestion: after watching a movie at typical volume for you, put your hand on the top of the receiver. If it's warm, fine. If it's hot, you may be reducing the life of your receiver.

    Better venting, defining your speakers as SMALL in favor of a dedicated external sub, and keeping the volume down a bit can all be used to manage this.
     
  3. JohnnyG

    JohnnyG Screenwriter

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    Mike, as long as the receiver isn't shutting itself off you should be okay.
     
  4. Greg Kolinski

    Greg Kolinski Second Unit

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    ck the HK sight ,in their FAQ there is a question about
    4 ohm speakers,yes its ok to run them.That had a big part in my getting the 520,it could handle my 4ohm fronts and center.
     
  5. Johnny Serrano

    Johnny Serrano Auditioning

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    I'm one of those that believes in properly terminating connections between the transmitting unit, medium carrier, and receiving device.
    If an amp transmits to a lower impedance speaker load, the amp will start to overheat in proportion to volume levels. Hopefully, the overheating or over-current protection circuitry will save your unit from damage.
    If an amp transmits at a certain power level and the speaker impedance is higher, the speaker will not be able to absorb all the energy, and it will bounce back as reflections to the receiver and cause the power level to drop. This isn't efficient.
    My vote is to always strive to terminate your transmitting and receiving devices.
    Here are some useful links,
    http://www.hometech.com/audio/volume.html
    http://www.tape.com/Bartlett_Articles/impedance.html
    http://www.conformity.com/0005reflections.html
     
  6. JohnnyG

    JohnnyG Screenwriter

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    An amp does not actually 'transmit' at a certain power level. Depending on the resistance of the speaker (which varies), more or less current is 'demanded' from the amp by the speaker. If the current demand is exceeded, a decent amp should shut itself off before damage is done.
     
  7. dennis.d

    dennis.d Auditioning

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    A low speaker impedance means it will suck more power from your amp than say an 8 ohm speaker. What you should be careful of is that your speakers do not 'clip'. Clipping is when your amp cannot continuously supply the power needed by your speakers (during high volume levels over extended period) and therefore start 'clipping' the tips of the waveform. This is when distortion sets in. If you subject your setup to this kind of abuse the fine copper wire in the voice coil of your tweeter will overheat, melt and eventually destroy it.
     
  8. Greg Kolinski

    Greg Kolinski Second Unit

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    I had an Onkyo first,then after I BOUGHT it[​IMG] I did some research,found that my fronts AR TSW 510's and the M%K center were all 4 ohm.The Onkyo was called a "high current"amp,but on the rear said 6 ohm minimum.I called Onkyo ,and they said dont try it,I t probobly would have lived,but I just wanted to be on the safe side of "maybe"[​IMG] .So I got the HK.Just to be safe I have a small fan mounted on teh wall behind the cabinat that blows over the rear of the reciever.
     
  9. Mike*Gillgannon

    Mike*Gillgannon Auditioning

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    Thanks for your responses!
    I've decided not to worry my pretty little head too much about this, since my listening tastes tend to be conservative in terms of loudness, the amp is well ventilated and it's not overheating.
    H/K stamping "8 ohms" on the back panel did cause some concern, however. They could do a better job of explaining things. But that's what you guys are for, right?
    --Mike
     
  10. Greg Kolinski

    Greg Kolinski Second Unit

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    [​IMG] I dont think the GUY who write's HK's manuals can undrstand them[​IMG]
     

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