Passive preamps

rs159
rs159 Posts: 1,027
edited July 2003 in Basic Hookup/Wiring Questions
What's the general consensous on passive preamps? Here's a link 5.1 preamp a guy built that intruiged me http://www.dact.com/6-gang_CT2_in_Secrets_of_Home_Theater___Hi-Fi.PDF

Of course he has no bass management, but Parts Express sells things called Fmods....

"What is an FMOD™? The FMOD™ is an active crossover simulator. It is better than a much more expensive electronic crossover that requires power to operate. FMODs™ are packaged in pairs and can be combined with other FMODs™ to obtain bandpass ranges or with other types of crossovers to change the slope and crossover frequency point. FMODs™ feature a 12 dB per octave crossover slope and are compatible with all RCA type input amps...simply place the FMOD™ in-line with the patch cable running between the source (head unit) and the amplifier. 24kt gold over brass construction, 10 volts maximum RMS input."

I figure you could use a bunch of them with some splitters for ghetto bass management.
Post edited by rs159 on
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Comments

  • BeginnersLuck
    BeginnersLuck Posts: 213
    edited July 2003
    Actually, they worked pretty well...I used the FMOD's from my stereo receiver into my second stereo receiver that was powering a passive sub and had no bass management.

    I think I bought the 50Hz crossover plugs...but for the $ it was much cheaper than buing a new amp with active crossover controls or a plate amp...

    I would agree that it is truely a "ghetto" mod...but is has much more practical application for use in a dual sub settup where you can set it up so that one sub gets 50Hz and up, and the other sub gets 50Hz and below...There are many fun things to try with these becasue the plugs are so easy to move around...

    Just in case your wondering, I don't use them any more.
    -BL
    TWFTPQ
    Receiver: Outlaw 1050
    Amps: Outlaw M-200 x 3 (Powering Mains and Center)
    Mains: RT800i; Center: CS400i; Surrounds: F/X500i
    Sub1: 214L Vented Tempest
    Sub2: 122L Sealed Tempest
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  • tryrrthg
    tryrrthg Posts: 1,896
    edited July 2003
    It's not that "ghetto" Audio Concepts (ACI) sells them on their web site and they make some of the most musical subwoofers around. Right up there with REL, but for a lot less money!

    http://www.audioc.com/accessories/Hipass.htm
    Sony KDL-40V2500 HDTV, Rotel RSX-1067 Receiver, Sony BDP-S550 Blu-ray, Slim Devices Squeezebox, Polk RTi6, CSi3 & R15, DIY sub with Atlas 15
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  • rs159
    rs159 Posts: 1,027
    edited July 2003
    IMHO it would prolly sound better than digital bass management. You go from digital to analog to digital then thru filters then back to analog again (assuming you're using analog outs). This way its just analog...filters.....amps. And weeeee........you can try different cables and y cables and everything.

    I think I'll build a stereo passive pre with some ratshack pots and mess around with different amps and sources and see if I like it. If I do then I'll move on to a more advanced unit like the one in the PDF I linked to that can control all 6 channels of a HT.

    Think about it: universal player....passive pre....amps. Put in a disc....and the damn thing just plays. If *I* built it I would have a few stereo in's for TT's or tape decks or w/e.

    BTW, heres the link to the PE page that has line level attenuators and filters and everything
    http://www.partsexpress.com/webpage.cfm?webpage_id=3&SO=2&&DID=7&CATID=48&ObjectGroup_ID=195&manuid=265
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