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Thread: Cheap, small 4ch amp Recycled OEM UNIT.

  1. #1
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    Cheap, small 4ch amp Recycled OEM UNIT.

    Hello everyone, this is my first post on the site.

    I am in the middle of putting a carpc into my 99 jeep grand cherokee.

    My setup so far:
    Hp mini 110 netbook
    7" Lilliput ct70 VGA
    cheap ebay BT module works w/ bluesoliel
    ELM 327 Bluetooth OBDII interface
    TOM TOM II bluetooth GPS receiver
    Centrafuse 4.0 Trial (not sure if its staying)
    Iguidance for Nav

    This post is about sourcing a cheap and small 4ch amp for powering the OEM vehicle speakers.

    I was looking around for low power small 4ch amps on ebay, I found a couple that were pretty small, but not quite as small as I liked.

    I was poking around in my basement last night and came across my old factory radio from my 1996 grand cherokee, I have since sold that jeep and this radio was just collecting dust so I decided I would pull it apart. What I found inside amongst all the PCB's was a separate 4ch power amp, this was driven by a separate pre-amp which is convenient.

    After some signal tracing and figuring out where the power all came from and where it had to go to, I had the unit out and on a bread board.

    This amp is small, very small, about 1"h x 1.5"w x 5"l I cut up the heatsink
    and screwed the two driver chips to it.

    I am testing it with an 8ohm house speaker and the source is coming straight out of a Cheap 4ch usb soundcard from ebay. It sounds pretty good, and is plenty loud.

    Here are some pics.

    The last one shows the unused bits of the unit.
    Attached Images Attached Images    

  2. #2
    Constant Bitrate tibimakai's Avatar
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    nivanov is using one with denoiser TDA7850 from Ebay. I'm building an Amp 9 from 41hz(100mmx60mm the board)

  3. #3
    Variable Bitrate
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    TDA7850 with denoiser is small, but not as small as OP's. The original TDA7850 is probably even smaller than what OP specified, though you'd need to desolder the RCA jacks and wire up your connectors directly to keep the footprint small.

  4. #4
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    Here are a few more pics if anyone is interested.
    I mounted a 5v regulator and some rca's to a protoboard as well as wired up all the
    stuff to the amp board. It works really well!! Now the only thing i have to do is figure out some kind of enclosure, as well as build a filter for the power, or maybe a 12v to 12v regulator.
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  5. #5
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    Just curious, why do you need the 5V regulated line? Also, a lot of amp chipsets work just fine with unregulated 12V - I have mine hooked up to the ACC circuit and it's working A-OK. If you can find the chipset name, you can google the specs and see if requires a regulated line.

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