Added a 2 channel amp - some observations

Discussion in 'Archived Threads 2001-2004' started by Stefan A, Apr 17, 2002.

  1. Stefan A

    Stefan A Second Unit

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    Today my used (new to me) Adcom 555 200x2 amp came in. So, before hooking it up, I listened to some music that I am familiar with on my Yamaha receiver (rx-v596). OK, it sounds good, like it always sounds. Then I hook up the amp to do a comparison. The music is fairly quiet at the beginning but gets pretty loud near the end. My initial impression after the first few seconds is that it makes it sound slightly louder. After listening through the whole tune, my impression is that the biggest difference is in the louder sections of music. The crescendos and transients are affected more. Transients are a little quicker and the impact is stronger. My wife, who I made do this comparison with me, described it as more blatty. Certainly not a term I want to associate with the sound of my system - but I have to agree somewhat. I then put on U-571 and watched (and listened) to the depth charge scene. Certainly a stronger impact - more in your face kind of sound as compared to my Yamaha alone. As far as the tonal characteristics, I felt that it had a slightly brighter sound then my Yamaha on music and movies.

    Of course, I was already expecting things to be a bit louder. But, I was hoping for things to "really open up" like I hear so many other people talking about. I was listening for a more expansive sound-stage. Again, only a slight difference - possibly a bit more in the center.

    I still need to listen some more, but right now I am not wowed by the difference. Could someone help me out with why I am not blown away? Do I need to step up to a better brand - maybe Parasound or Rotel? Is my Yamaha really that good?

    My mains (which are what is affected) are Mirage OM-10's. I am using Monster "standard" interconnects between the amp and the receiver (nothing special I know).

    My initial purpose of buying this amp is to power my sound system in my school band room. For that, I don't care as much about soundstage, ect... Just Power. So, I am definitely not stuck with it. Would I be better off just selling to my school and getting myself something better?

    Thanks
     
  2. Saurav

    Saurav Cinematographer

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    How efficient are those speakers? The more efficient they are, the less power they'll need to handle transients, and the less of a difference you'll hear by upgrading amp wattage. At least, that's what I think.
     
  3. John Tompkins

    John Tompkins Supporting Actor

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    Thats a tough one, the adcom is known to be a tad bright, but not in comparision to a yamaha[​IMG]
    It should be a large difference in quality of sound not just loudness even when paired with effecient speakers. I will also say that I went through about 10-15 different amps in my system before I found the one that was (my) perfect match.
    One thing to keep in mind is that the yamaha used as a pre-amp is possible(probably) not doing any justice for the adcom amp. In my mind the pre-amp plays a bigger role in changing the (sonics) of your system then does an amp.
     
  4. John Garcia

    John Garcia Executive Producer

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    Calibration? You didn't mention anything about that. Did you recalibrate after hooking up the new amp or just run it the way it was? Have you ever calibrated at all? While I don't think this is the issue, it might make some difference also.

    Yamaha's site did not list the power output for this unit, but I am guessing it is around 70-80wpc? If that is the case, then yes you should have heard a noticable jump in cpability for LOUD, while the overall sound quality is still determined by both the source and the processor.

    I have no idea how your Yamaha sounds, but I'd give it some time, do some more critical listening, and if you're not happy with it, then sell it.
     
  5. Stefan A

    Stefan A Second Unit

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    To answer the questions:

    The Mirage Om10's are 91db for sensitivity

    For 2 channel, it is calibrated. I still have to calibrate the mains to the others for 5 channel.

    The Yamaha is 100 WPC.
     
  6. Mike_T_

    Mike_T_ Stunt Coordinator

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    Do you have your mains set to large? I think the Yammy also has a Low Output filter or something like that that allows more Bass to go to the mains. Really, sometimes I first turn on the amp and listen to music and aren't initially blown away, but after some time you get to know the personallity of the amp and begin to hear things you never did before in the music. Now when I say that, I understand you really DID hear that part of the music but it wasn't pronounced enough to notice. I got freaked out the other night listening to Fleetwood Mac, during the refrain it sounded like someone was right behind me! I never had that "problem" until I attatched an Amp...
     
  7. Kevin Alexander

    Kevin Alexander Screenwriter

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    Stefan,

    I think you should give it a little time to go through your software. After I emailed you on this last week, I purchased an Acurus A125X5 amp here locally for my receiver which is the same as yours. I could actually feel the power to spare as I spun some of the DVDs, and for the first time in a long while, I could actually feel the presence of my surround speakers. I am not finished w/ my evaluation, but I, too, was not immediately impressed w/ external amplification, but now I'm satisfied.
     
  8. Stefan A

    Stefan A Second Unit

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    Kevin,

    That surprises me - that a 125 wpc amp makes such a difference when your receiver already has 100 wpc. I was under the impression that you need to double the wpc to make a difference - which is why I have been looking at 200 wpc amps. Maybe you or someone else can explain.

    Should you go for the most wattage you can afford - or is there a definite ceiling where you should aim for? Is there a formula based on speaker sensitivity, room size, ect... that determines this?

    Stefan
     
  9. Kevin Alexander

    Kevin Alexander Screenwriter

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    Even though the Yammies are rated at 100WPC, I think the #'s are actually quite lower.
     

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