1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Receiver output selector question

Discussion in 'AV Receivers & Amplifiers' started by moss6, Jan 25, 2003.

  1. moss6

    moss6
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    I've always wondered what effect an amplifiers output (ohm wise) has on speaker performance given that the output is equal to or above the impetance of the speakers. In my case I am using 4ohm main speakers with the front effects, front center, rear surround and rear center being 8 ohm speakers. I am using the 8 ohm output on the receiver because I am driving the 4 ohm mains with a separate amplifier from the main pre-out section of the receiver.
    What differance would there be if I change the receiver output to the 4 ohm setting; any differance in speaker driving capabilities in regards to tone, range, volumn? Or would this only contribute to more heat output of the receivers amps?
    Thanks,
    Randy
     
  2. lynx

    lynx
    Well-known Member

    Joined:
    Jan 20, 2002
    Messages:
    4,633
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    It always rains.
    Ratings:
    +301
    If you switch the selector to 4 ohm,then to the best of my knowlege in your set up there would be no difference.If on the otherhand you introduce a 4 ohm load to the amp, then the amp ( now switched to 4 ohm) would produce less power ( it would normaly develop more power ). It is basicaly a protection device to prevent over streaching it when driving difficult loads.Hope that makes a little sense. :)
     
  3. moss6

    moss6
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    So switching to 4 ohms has no effect on the 8ohm speakers or to the amp's load level as long as a higher load is not introduced?
    If this is the case I do not understand why the switching is appropriate at all; it would seem that the receiver would be better served, protection wise, to always be operated at its highest reserve level if heat were not a factor.
    ?
    Randy
     
  4. lynx

    lynx
    Well-known Member

    Joined:
    Jan 20, 2002
    Messages:
    4,633
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    It always rains.
    Ratings:
    +301
    When switched to 4 ohm mode the amps power delivery is being held back.
    Say for instance it delivers 100w into 8 ohms, switching the amp to drive a 4 ohm load then conecting 4 ohm speakers it may now only deliver 80w instead of an expected 120w.
     
  5. moss6

    moss6
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    That sounds somewhat backwards as the receivers rating is 150 W at 8 ohm, 180W at 6 ohm, 240W at 4 ohm and 340W at 2 ohm.
    Also my amplifier is much the same being 430W at 8 ohm and 660W at 4 ohm. Please explain, as I'm a bit dense I suppose.
    Randy
     
  6. sounddog

    sounddog
    Well-known Member

    Joined:
    Dec 11, 2002
    Messages:
    3,373
    Products Owned:
    0
    Products Wanted:
    1
    Trophy Points:
    107
    Location:
    Leicestershire, UK
    Ratings:
    +461
    If you're driving the 4ohm (main fronts) via a separate power amp then the switch should be set at 8ohm - i.e. what the rest of the speakers are ... when using the pre-outs the AV Amp doesn't care what speakers are attached to it.


    Victoria
     
  7. lynx

    lynx
    Well-known Member

    Joined:
    Jan 20, 2002
    Messages:
    4,633
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    It always rains.
    Ratings:
    +301
    This is the point of that switch.It is holding back the amps power delivery into low ohmic loads so it doesn't come to an early death. :) Is it Sony by any chance ?
     
  8. moss6

    moss6
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    The receiver is a Yamaha, RX-V1. I still would like to have some explaination to my original question however; what effect does the setting of a receivers output load of 4 ohms have on the 8 ohm speakers?
     
  9. lynx

    lynx
    Well-known Member

    Joined:
    Jan 20, 2002
    Messages:
    4,633
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    It always rains.
    Ratings:
    +301
    None. Your getting this @rse for elbow :) . The load from the speakers has an effect on the rec, not the other way around. Your rec does not have an 'output load of 4 ohms'. It is protecting it's self against the possible repercutions of being asked to drive a 4 ohm load.
     
  10. mbbx0bbr

    mbbx0bbr
    Active Member

    Joined:
    Sep 18, 2002
    Messages:
    407
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    UK- North
    Ratings:
    +11
    so if u were to plug in some 4ohm speakers into an amp rated at 8ohms what would happen to:

    1) The speakers

    2) The reciever

    3) The quality of the sound produced

    ??

    My amp is rated from 6-16 ohms, and says can do 100W at 8ohms, and 145w at 4 ohms. My speakers says they require 80w into 4 ohms. Any more info needed just ask.
     
  11. lynx

    lynx
    Well-known Member

    Joined:
    Jan 20, 2002
    Messages:
    4,633
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    106
    Location:
    It always rains.
    Ratings:
    +301
    1) If you mean what detrimental effect would happen - Nothing.

    2) It *may* become stressed if not designed to drive that load.

    3) Don't know. Never tried it. However i would expect the output devises to have a shorter working life if used like this in anger.

    You may have the wrong end of the stick in saying your speakers require 80w.The manufacturer normaly quotes a range within which the amplifier should be rated.Useing a more powerful amp does not mean it *will* damage the speakers.
     
  12. mbbx0bbr

    mbbx0bbr
    Active Member

    Joined:
    Sep 18, 2002
    Messages:
    407
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    UK- North
    Ratings:
    +11
    I want to purchase a pair of Linn's that are quataed at 4 ohms, and say they need min of 80W to 4 ohms.
    manufacturer says
    * Input Impedance: 4ohms nominal

    * Amp Requirments: at least 80w per channel into 4 ohmsl



    My amp , denon says (from Manual)

    Power Amplifier rated output:
    Front: 80W+80W (8ohms, 20hz-20khz with 0.08% T.H.D)
    110W + 110W (6ohms, 1khz with 0.7% T.H.D)

    Dynamic Power:
    100W * 2 ch (8ohms),
    145W *2 ch (4ohms),
    170W * 2 ch (2ohms)

    output terminals:
    Front: 6 - 16 ohms


    I have been told by some that the denon 1803 will not drive these speakers. I have been told by denon that they will but i will get better use of the speakers with a better amp i.e 3802.

    Basically will it sound bad, or would i see some of the benifits of these speakrs? or would i be better off going for 8ohm speakers at the same price range?
     
  13. sounddog

    sounddog
    Well-known Member

    Joined:
    Dec 11, 2002
    Messages:
    3,373
    Products Owned:
    0
    Products Wanted:
    1
    Trophy Points:
    107
    Location:
    Leicestershire, UK
    Ratings:
    +461
    Yes it will work ... though your amplifier may get a little warmer than normal as it's not designed to drive 4ohm speakers (which are more difficult to drive). As long as you arn't trying to listen at high level you should damage neither your speakers nor your amp.

    And yes ... a 3803 will drive them better ... but there again a 3803 will drive most speakers better than a 1803.


    Victoria
     
  14. mbbx0bbr

    mbbx0bbr
    Active Member

    Joined:
    Sep 18, 2002
    Messages:
    407
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Location:
    UK- North
    Ratings:
    +11
    The 4 ohm speakers in question were some Linn keosa's.

    Now would I be better off with them or some 8ohm Mission M74i's?

    Assumming I am to use the denon 1803.

    Which speakers would give me better sound with the 1803, i can get either for a similar price.
     

Share This Page

Loading...