Receiver runs hotter when NOT using the amps?

Discussion in 'Archived Threads 2001-2004' started by Salvatore Restivo, Aug 26, 2002.

  1. Salvatore Restivo

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    I've been wanting to take my first step toward separates in my home theater. I added a set of Denon POA-8300 and POA-8200 amplifiers to power my 5.1 speaker setup. Now I use my Denon AVR-4800 receiver as a pre/pro only. My expectation was that removing the burden of driving the speakers from the receiver would cause it to run cooler. But, instead, it runs much hotter! Why would it do that? It's not working as hard. (The new external amps run quite cool. And I'm happy with the sound.)
     
  2. David Berry

    David Berry Stunt Coordinator

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    Salvatore,

    Is the receiver in the exact same place and have the same ventilation as before? Also, is it possible with the outboard amps that their heat is mixing with the Denon? I have noticed the same phenomenon with my receiver (3802 and Bryston 3B-ST) when running 2-channel stereo; however, the reason is that in my specific setup the Bryston is on a lower shelf, and just by heat convection, some of it will "roll over the top" of the Denon. This gives the impression that the Denon is actually running hotter than before.
     
  3. Salvatore Restivo

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    That's an interesting consideration. Actually, I've got a five-shelf rack. Old setup, bottom to top: receiver, Panamax, DVD player, CD changer, VCR. New setup, bottom to top: 3-channel power amp, CD changer, receiver, DVD player, 2-channel power amp. The Panamax and VCR are now in a different piece of furniture. The thing is... the new power amps are cool to the touch, so I don't think they are cooking the receiver. The receiver is the only component that gets hot. Thanks for responding.
     
  4. Paul Clarke

    Paul Clarke Supporting Actor

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    Does the new receiver shelf location have the same ventilation space as before?
     
  5. Salvatore Restivo

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    Yes, the ventilation space is the same as before. The receiver has 2 inches of clearance on each side, 4 inches above, and a foot in the back. That's about what it was in the old setup. The rack is open at the back, but has a plexiglass door in the front. The rack itself has not changed.

    I suppose many people on this forum use a receiver as a pre/pro only, connected to an external amplifier. Has anyone else seen heat production increase in the receiver after adding an amp? Is this a common side-effect of this configuration? Or is it particular to the Denon AVR-4800 model? Or is there something wrong with my particular unit?

    I sent an email to Denon tech support explaining the situation and asking their advice. My worry is that the extra heat is hurting the receiver, and maybe I should just lose the external amps. Or maybe the heat is normal, and I should stop worrying.
     
  6. Yogi

    Yogi Screenwriter

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    That is quite abnormal to have more heat when the amps are not being used. This sounds like Class A amps that idle hotter then when they have a signal playing and we all know that there are no receivers that use Class A amplification.

    So there must be something else going on here. My receiver heat production decreased after I switched the front L/R load to a separate amp. I am sure most others have seen this too that their heat production decreases after they move their amplification load outside the receiver.
     
  7. Chas_T

    Chas_T Supporting Actor

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    Salvatore,

    When I was using external amplification and my receiver (Sony STR-DA777ES)strictly as a pre/pro, my receiver temp stayed the same.

    It was still hot to the touch using the amps or not. I thought it might cool down a bit, but it did not. The temperature remained the same. Or it was not a noticable difference to the touch of my hand where I could write there was a heat/cold increase or decrease.
     
  8. Paul Clarke

    Paul Clarke Supporting Actor

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    If there is nothing wrong or different with the setup you might simply chalk it up to normal vertical temp variation between shelf heights. The receiver did use to be on the bottom, correct?

    Also, are the only connections between the 4800 and the amps the pre-out interconnects?
     
  9. JackS

    JackS Supporting Actor

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    As Chas T stated, my Da777es runs at least as hot as it did before installing external amps 2 years ago. I take it to be normal and no longer pay it any mind. I did read a thread some time ago in which a receiver user was going to look into decoupling the receivers amps via a little electronic surgery, but never heard another word about it. The only advantage here would be less power consumption although, I'm not sure as to how much power the 777 is actually using. My final thought is, if the receiver is operating within its temperature range, no harm should come from it.
     
  10. Amir

    Amir Agent

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    I have a similar problem. I use a Denon 2800 as pre/pro with Parasound 2205. Running stereo all day, the Parasound barely gets warm but the Denon feels hot - won't burn your hand but much warmer than the Parasound. Go figure!! I was told that it has to do with the quality of power supply and electronics in the system. The parasound is very heavy with heat-sink/fins and built to handle much heavier loads.
    Amir
     
  11. Ronald Aguilar

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    I am currently running a Denon 4800 with 2 external amps (Parasound 1500a and Denon POA 8300). My Denon receiver doesn't get hot at all. The receiver is still powering the back 3 channels of my HT.

    Ron A.
     
  12. Michael WB

    Michael WB Auditioning

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    I have a 2-channel amp powering my main speakers and my receiver is just as hot when listening in stereo where I don't use the recievers amps as it is when playing surround where it powers the center and rears.

    I found that a little strange, I was expecting it to be cooler in stereo, but from what I see here it's not that unusual.

    Michael
     
  13. BobRoulier

    BobRoulier Second Unit

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    Im using a 49tx as a pre-pro along with a parasound 2205 they both get very hot! Im using 4 channels on each the parasound has adequate room in the rack and the 49tx sits on top open air. I have tried different things and they both run hot no matter what! either way they both sound fantastic[​IMG]
    Bob
     
  14. David Berry

    David Berry Stunt Coordinator

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  15. Salvatore Restivo

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    Thanks for all the input. A Denon rep told me yesterday that their receivers normally run hot, and that if mine is not malfunctioning (which it isn't), I shouldn't be too concerned.

    Paul Clarke: Yes, the only connections between the receiver and new amps are via the receiver's pre-outs.

    Ronald Aguilar: Your setup sounds quite similar to mine. I think maybe the heat is related to the fact that I'm not driving any speakers with my receiver. If my receiver is actually operating in a class A sort of mode, then that would explain it. You indicate that your receiver is still driving the back 3. That might be enough to push your receiver out of class A. It's a plausible theory, anyway.
     
  16. Yogi

    Yogi Screenwriter

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    I think all mass market receivers operate in Class AB. Maybe the first watt or two is in class A. Which is still not enough to justify somuch heat. Even a great separate amp like the Parasound 2205 which supposedly has about 15-20 watts of class A per channel doesnt idle very hot, so there is no reason for the 4800 to idle much hotter. Also doesn't the 4800 have a fan? In that case you can rest easy?

    Also as long as there are no performance issues you dont have to worry about heat. I have used B&K 5000ii in my setup for a couple of months and during movies at reference levels (if I know what that is) it used to be too hot to touch and yet never failed me or lost its composure, even once. So dont worry too much about heat as long as it doesn't go into protect mode.

    I think its time for you to stop worrying about heat issues and enjoy you sweet setup.
     
  17. Salvatore Restivo

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    Denon indicates that the receiver's amp section is, indeed, class AB. When power output is below a certain threshold, it operates in class A mode, which brings with it increased heat output. In my case, power output from the receivers's amp section is zero. So, I think I've got my explanation for this initially counter-intuitive phenomenon.

     
  18. John Chow

    John Chow Second Unit

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    Theory: With the internal amps being used, the heat level gets hotter, so the internal fan turns on sooner/is on more constantly, which cools off the unit. When the internal amps are not used, the temperature possibly borders on the edge of whether the fan gets turned on or not, and this temperature is hotter than after the fans start blowing.
     
  19. Salvatore Restivo

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    John Chow: Before I added the external amps, the receiver's built-in fan never activated. There is a clearly audible cue when the fan activates. The first time I heard it was this past weekend when I installed the new amps.
     

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