Calling Amp/PreAmp experts....Is it OK to add 2 Preamps?

Discussion in 'Archived Threads 2001-2004' started by NickSP, Oct 30, 2002.

  1. NickSP

    NickSP Supporting Actor

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    This is to expand and grab the attention of amp experts again. Chet posted his concerns in a post below and I added to that thread about my concerns too.
    Problem being that the DVD sound output is anemic when compared to CD/VCR/DSS, etc. I have tried everything from changing cables to checking polarities to assigning different inputs but no dice. DVD volume still remains anemic when compared at the same volumes for other sources. I have to crank up my processor close to "0" for a good sound but at that level with a CD playing bleeds my ears out.
    The question is can I add a seperate preamp between the first preamp and the amp by using the 5 channel output from my first preamp and feeding it to 5 channel input of the second preamp and then connecting the second preamp to the amps? Is there any danger in doing so?
    For reference, I am using a Proton preamp/processor with AMC amps(2) rated at 150W/channel X 3.
     
  2. BruceD

    BruceD Screenwriter

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    Are you using the analog out ports on the DVD that have an internal DVD controlled digital volume control, or the full-output DVD analog outs without volume control?

    Remember anything that enters the processor is probably going through another A>D and then D>A process unless the processor defines the inputs specifically as an analog bypass.
     
  3. NickSP

    NickSP Supporting Actor

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    Bruce, I am not using analog ouputs from the DVD at all, only digital. I have tried the Coax and digital inputs both but they came back with same results. I am connecting the CD player via Optical digital output and the volume seems great.
     
  4. Saurav

    Saurav Cinematographer

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  5. NickSP

    NickSP Supporting Actor

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    Saurav, thanks for the reply, I knew you would be inputting on this one. I have an old SHAC500 from Technics and here is how I intend to hook up the system. All input sources will be fed to the Proton, take the 5 channel out from Proton and hook them to 5 channel inputs on the SHAC500. Take the 5 channel outputs from the SHAc500 and hook them to the Amps. Should this connection be OK?

    "None that I can think of. Just be careful you don't hook up an output to an output or something silly like that.
    "
    What exactly would be hooking up an output to an output?
     
  6. Saurav

    Saurav Cinematographer

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    First, what would you achieve by doing this? I thought you wanted 2 preamps so that the DVD player could go through an extra preamp which would let you 'normalize' its volume with respect to your other sources. If all the sources go through both preamps, I don't understand why you're doing this.
    Also, in general you're better off with less components in the picture, at least IMO. I'm of the school of thought that every component hurts the signal, nothing improves it, so the best you can hope for is to hurt the signal as little as possible. If you subscribe to that philosophy, you wouldn't use 2 preamps unless you had a very good reason to. So, yes, what you propose will work, but I'm not sure I understand the motivation behind it.
     
  7. NickSP

    NickSP Supporting Actor

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    OK, I get it. I thought by using 2 preamps I would somehow be able to increase the gain for DVD? Perhaps Not? I thought that that would result in a dual volume control.
     
  8. Jonathan M

    Jonathan M Second Unit

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    Hi Nick,

    A couple of points. First of all, if you feed the SH-AC500D by it's 5 channel inputs, the volume control won't work - it's a direct bypass. I think what you are trying to do is put a separate preamp between the DVD player and your main preamp to boost the DVD levels to that of the other sources.

    This is possible, but with your current gear you'll need to go as follows:

    DVD Player -> Digital -> Technics SH-AC500 -> Analog -> Proton -> Amp.

    Thus, the SH-AC500 will be doing the decoding. Adjusting the volume on the Technics will help you get closer to the other source volume levels.

    I would definitely try doing what Saurav suggested above - try another DVD player, and try playing a CD in the DVD player and in the CD player.

    CD Player ANALOGUE outputs are generally pretty high, but you are using Digital - I don't see why you are getting such a large difference. A small difference would be due to the fact that DVD's have a higher dynamic range, thus the average level is lower than on CDs, but that shouldn't produce this much difference.

    Bottom line - check another DVD player if possible to see if yours is faulty in some way.

    Hope this helps.
     
  9. Saurav

    Saurav Cinematographer

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