Simple DIY Pre-Amp

Discussion in 'Home Theater Projects' started by John Klaassen, Sep 13, 2003.

  1. John Klaassen

    John Klaassen Auditioning

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    I have a little project that I want to try to make a simple pre-amp for. It just needs to have system volume and individual channel volume controls. Does anyone know of instructions somewhere on the internet on how I could do this. I'm going to make it 5 channel, but instructions for 2-channel could just be expanded. Thanks.

    --John Klaassen
     
  2. Michael R Price

    Michael R Price Screenwriter

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    This is fairly complicated, but I would start searching around at http://www.diyaudio.com/forums/forum....php?forumid=4. The preamp circuit itself is not very difficult, but getting accurate level controls for all 6 channels might be... you might be able to use a 6 deck potentiometer (I'm not even sure those exist) and then another independent potentiometer for each channel? I think most multichannel preamplifiers use a microcontroller switching relays to set the volume with a single potentiometer or rotary encoder. A microcontroller could also provide data input to multiple PGA2310 (I think) IC volume controls.

    A 2-channel preamp would be much easier, since getting a stereo volume control and balance control is no big deal.
     
  3. Doug_M_Fraser

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    Try the Danish Audio Connect at

    www dot dact dot com/html/applications.html

    for a 5 channel DIY preamp.

    Replace the dot with a . and remove the spaces. Sorry for a reply in this form but I kept getting an error message saying I have not been a member long enough to post a URL.

    Doug
     
  4. Michael R Price

    Michael R Price Screenwriter

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    Aha, it is true that DACT has a 6 channel attenuator (and that preamp too). That's who I was thinking of when I mentioned the multi-deck potentiometer. But that stepped attenuator itself (never mind the rest of that preamp example) costs $400. Holy moly.

    Just making a 2-channel preamp, or using a commercially built multichannel preamp, looks better to me. And I can't say I know enough to offer specific ideas if you do decide to build the 6-channel volume control.
     
  5. ThomasW

    ThomasW Cinematographer

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    There are lower cost ganged carbon/plastic pots available to the DIY builder. Of course they don't sound nearly as good as stepped attenuators.

    And unless one needs 'pre-amplification' for a phono section, a 'passive' preamp works quite well for line-level components. And they cost a whole lot less than an active line stage.
     

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