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  1. #1

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    Default any instructions on how to make a basic passive pre-amp?

    help me out, what parts are invloved to make a simple volume controled single input/output passive pre? this will be for the sonic impact amp setup i have... Thanks


    parts needed?

    project box
    what kind of volume pot? and what ohm? 5k 10k, 100k ohm?
    any resisters involved?

    where to find insulated input rca jacks?

    Thanks a million for any help
    MY HT RIG:
    Sherwood p-965
    Sherwood sd871 dvd
    Rotel 1075 amp x5
    LSI15 mains
    LsiC center
    LSIfx surround backs
    Lsi7 side surrounds
    SVS pb12/plus2


    2 Channel Rig:

    nad 1020 Pre-amp
    Rotel 1080 stereo amp
    Polk sda 2B
    kenwood grunt Tuner
    realistic lab 450 TT
    Signal cable IC

  2. #2

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    I'd start with a 50K pot, make sure its tapered, not linear. Linear will work, but tapered pots work better for audio applications.

    Parts express has input jacks with a plastic 'disc' to keep the ground off the chassis.

    Cheers,
    Russ
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.

  3. #3

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    This should answer some of your questions:
    Attached Images  
    Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
    Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
    Jordan JX92s : MF X-T100 : Xray v8
    Backburner:Krell KAV-300i

  4. #4

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    That's a mod squad line drive- it's actually on ebay right now for $80... Note that all the grounds are shared & attached to the chassis. One improvment would be to get yourself a rotary switch that will switch both ground & signal on both left & right, but they aren't cheap- you'd need a 4 pole, x position (where x is your # of inputs). That would do a lot to eliminate any crosstalk.
    Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
    Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
    Jordan JX92s : MF X-T100 : Xray v8
    Backburner:Krell KAV-300i

  5. #5

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    FWIW I sent an email to Gary at Dodd requesting a totally passive pre based on his mid-level tubed Dodd chasis. 3 inputs, 1 output;

    $650 w/Alps
    $850 w/Dact

    Now that would be unique, and I'm seriously considering it...
    Last edited by steveinaz; 05-26-2005 at 05:21 PM.

    Source: Squeezebox Touch/CIA Power Supply
    DAC: Benchmark DAC/PRE
    Linestage: Placette RVC Passive
    Power Amp: Parasound HCA-1500A
    Speakers: Harbeth Compact 7ES-3 Monitor
    Subwoofer: SVS PB12-NSD

  6. #6

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    That would be interesting Steve. I think you should go for it, that way I can play with it before it gets shipped out.

    ;)

    Cheers,
    Russ
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.

  7. #7

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    If I do it, absolutely--take her for a test ride. I love runnin my system passively, it's just a pain in the ass trying to balance 2 knobs on the back of the amp.

    I'm still debating going fully passive or maybe go the Monolithic PA-1, just in case I ever run into a source that needs a little extra push...

    Source: Squeezebox Touch/CIA Power Supply
    DAC: Benchmark DAC/PRE
    Linestage: Placette RVC Passive
    Power Amp: Parasound HCA-1500A
    Speakers: Harbeth Compact 7ES-3 Monitor
    Subwoofer: SVS PB12-NSD

  8. #8

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    would be cool far as the custom job.... But way to much money. for a passive IMO..

    Thanks for the info guys, I'll make this if i can find a cool project box.. or a match to my SI amp project. Were talking sonic impact cost on the passive pre for my bedroom not "High end" LOL... :)
    MY HT RIG:
    Sherwood p-965
    Sherwood sd871 dvd
    Rotel 1075 amp x5
    LSI15 mains
    LsiC center
    LSIfx surround backs
    Lsi7 side surrounds
    SVS pb12/plus2


    2 Channel Rig:

    nad 1020 Pre-amp
    Rotel 1080 stereo amp
    Polk sda 2B
    kenwood grunt Tuner
    realistic lab 450 TT
    Signal cable IC

  9. #9

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    I kind of figured you were wanting to build one, just thought I'd throw that out there.

    I've done a ton of searches lately on "DIY preamp" and found lots of info...give it a shot.

    Source: Squeezebox Touch/CIA Power Supply
    DAC: Benchmark DAC/PRE
    Linestage: Placette RVC Passive
    Power Amp: Parasound HCA-1500A
    Speakers: Harbeth Compact 7ES-3 Monitor
    Subwoofer: SVS PB12-NSD

  10. #10
    Old Polk
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    Since it's for the bedroom, here's an fairly inexpensive kit w/remote:

    Passive pre with remote
    Be-Bop-A-Lula, Baby What I Say

  11. #11

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    cool kit.....
    MY HT RIG:
    Sherwood p-965
    Sherwood sd871 dvd
    Rotel 1075 amp x5
    LSI15 mains
    LsiC center
    LSIfx surround backs
    Lsi7 side surrounds
    SVS pb12/plus2


    2 Channel Rig:

    nad 1020 Pre-amp
    Rotel 1080 stereo amp
    Polk sda 2B
    kenwood grunt Tuner
    realistic lab 450 TT
    Signal cable IC

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