Lowering amplifer gain to reduce hiss?

Discussion in 'Archived Threads 2001-2004' started by Aaron Cooke, Sep 30, 2002.

  1. Aaron Cooke

    Aaron Cooke Second Unit

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    I recently upgraded a lot of my equipment and am experiencing a lot more hiss than i'm used to. I'm not blaming any of my components, I don't really care where the hiss is coming from. If i lower the gain on my amplifer and compensate by raising the levels the speakers are set at coming from the pre/pro, the hiss diminishes My question is, is there any disadvantage/danger in doing this. I'm running a B&K 7270 amp, Outlaw 950 and Klipsch RF-7/RC-7 For what it's worth, I don't notice an abnormal hiss coming from my surrounds which are def tech BP2X's so I'm assuming it has a large part to do with the higher efficiency of the Klipsch.
     
  2. Martice

    Martice Screenwriter

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  3. Bill Polley

    Bill Polley Second Unit

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    I have very little (next to none) hiss with my 950 and Parasound amp. The amp had a blown channel (I only used it for 2 channel, when I went to surround I noticed it) and the dealer is fixing it under warranty. The loaner Yamaha I got hissed very loudly when I hooked it up as an amp. By turning the volume down on the Yamaha, effectively lowering the gain, and raising the volume on the 950, the hiss went away.
     
  4. Kevin C Brown

    Kevin C Brown Producer

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    The Outlaw does tend to exhibit more hiss in systems with more sensitive speakers, and amps with more gain.

    Hey, stupid question here:

    More gain = ... more power?

    (I have 2 Acurus 200 per channel, 3 channel amps. Before this I had a Nakamichi 2 channel 150W/channel + 1 Acurus 100W per channel, 3 channel amp. The Acurus 200W/channel definately had more hiss than the Nak at 150W/channel. All of those hisses though were only audible at the tweeters.)
     
  5. Aaron Cooke

    Aaron Cooke Second Unit

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  6. BruceD

    BruceD Screenwriter

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    In the latest replies on the Outlaw forum, it appears a consumer comparison to the Atlantic P-2000 finds:
    . . . . results = exactly the same sound as the 950.
    Also, it appears (comments from an owner) that Outlaw told him hiss from 4'feet is normal.
    read here
     
  7. Saurav

    Saurav Cinematographer

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  8. Aaron Cooke

    Aaron Cooke Second Unit

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    thank you saurav, that was exactly the information i was looking for.
     
  9. Kevin C Brown

    Kevin C Brown Producer

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    Saurav- Cool, thanks. Hey, have you been following the Outlaw 950 hiss issue at all?

    For me, the hiss is volume independent, doesn't depend on source or source type (coax digital, 2 or 5.1 channel analog), and goes away when I turn the 950 off but leave my amps on.

    I'm convinced the problem is in the 950's analog output stage, but that's just a big fat guess...
     
  10. Saurav

    Saurav Cinematographer

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  11. Craig Ball

    Craig Ball Second Unit

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    I just sent my 950 back yesterday. I have Klipsch speakers and Acurus amps, these were hooked up to a H/K 520 used as a pre-pro and had no hiss issue at all. In comes the outlaw and HISS is awful. Needless to sy the H/K's back and the hiss gone.

    Craig
     
  12. Russell _T

    Russell _T Supporting Actor

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    The H/K 520 employs muting circuitry that kicks in when there is no signal from the source. You will most likely get hiss when it receives a signal, but you probably can't hear it over the music or dialogue. It's too bad Outlaw didn't employ this feature.
     

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