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Thread: Hacked Radio into HU?

  1. #1
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    Hacked Radio into HU?

    Has anyone tried making their own headunit with volume control? Im thinking about finding a small LCD digital radio, adding simple master volume control, AM/FM/Computer switch, and outputing audio to a power amp?

  2. #2
    MySQL Error scott_fx's Avatar
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    thats a good idea but i think most of us want a solution that can be controlled by our touchscreens and integrated into our front ends.

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  3. #3
    Raw Wave shotgunefx's Avatar
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    Not quite the same, but I just finished up ditching my headunit and driving the amp with a Sirius Starmate radio.



    For my car, METRA makes a "factory integration harness". It gives you rca inputs to the amp. A few issues, first is that you might need to figure out how to turn the amp on. My car required about 5ma to the wire labeled "power antenna lead" (my car never comes with a power antenna ),

    Second, the volume isn't quite loud enough. Most lineout outputs supply around 2.2v. My head unit puts out about 5v. So I'm working on a little amplifier know with radioshack parts.

  4. #4
    MySQL Error scott_fx's Avatar
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    thats a nice install shotgunefx. have you ever considered getting a line driver instead of building an amp?
    New System in progress:
    M10k
    Phaze TD1500 ~> Dynaudio MD130
    Phaze TD1500 ~> Seas g18rnx/p
    Zapco Ref 500.1 ~ 12" tc-9
    Behringer DCX2496 ~ Envision Electronics psu
    Transflective Xenarc

    My Car Pc Install
    My Boat Pc worklog

  5. #5
    Raw Wave shotgunefx's Avatar
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    Quote Originally Posted by scott_fx
    thats a nice install shotgunefx. have you ever considered getting a line driver instead of building an amp?
    Thanks. I'm going to redo it in a bit and probably add some bargraph meters on each side.

    I'm not much of an audio guy, so correct me if I'm wrong. Isn't a line converter for driving speakers directly?

  6. #6
    MySQL Error scott_fx's Avatar
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    this is a 'line-driver' which bumps up the voltage of your line output. i currently have an audio control unit but it is probably overkill for your situation.

    here is a relatively inexpensive (but good) unit:
    http://cgi.ebay.com/ws/eBayISAPI.dll...780942850&rd=1
    New System in progress:
    M10k
    Phaze TD1500 ~> Dynaudio MD130
    Phaze TD1500 ~> Seas g18rnx/p
    Zapco Ref 500.1 ~ 12" tc-9
    Behringer DCX2496 ~ Envision Electronics psu
    Transflective Xenarc

    My Car Pc Install
    My Boat Pc worklog

  7. #7
    Raw Wave shotgunefx's Avatar
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    Quote Originally Posted by scott_fx
    this is a 'line-driver' which bumps up the voltage of your line output. i currently have an audio control unit but it is probably overkill for your situation.

    here is a relatively inexpensive (but good) unit:
    http://cgi.ebay.com/ws/eBayISAPI.dll...780942850&rd=1
    Damn! Beautiful car and install.

    Well, the amp I'm working on, it almost works too noisy. Based on LM386's. I think the problem is construction. If I can find one of these locally, I might just say hell with it and buy it as I'd much rather work on other aspects of the install this weekend. Though I like the idea of being able to 1. Limit the maximum volume in case the pc goes screwy (the sirius is going to go to the pc, which will then drive the amp) and 2, having a nice volume control on the dash. Especially at the moment as I keep yanking everything in and out all the time.

  8. #8
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    sorry

    Interesting, I believe I'm going to go ahead and start this project. With regards to voltage your saying a normal output of say a sirus, walkman, ipod, am/fm radio is 2.2 volts when a normal pre-amp output is closer to 5?

    I believe I have a simple circuit in my electronics lab notebook for a pre-amp circuit we built in class. Let me know if you wish me to send you details.

    I want external am/fm/weather radio as a backup just incase the computer kicks the bucket or something. Since the HU will only have a small LCD screen tuning, volume, and maybe some preset buttons I can also integrate some hotbuttuns for the computer, possibly a female 2.5mm(headphone size i believe?) jack for friends to plug in ipods etc...

    Great forum, just want to say hi to everyone.

  9. #9
    Raw Wave shotgunefx's Avatar
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    Quote Originally Posted by eljimbo
    Interesting, I believe I'm going to go ahead and start this project. With regards to voltage your saying a normal output of say a sirus, walkman, ipod, am/fm radio is 2.2 volts when a normal pre-amp output is closer to 5?

    I believe I have a simple circuit in my electronics lab notebook for a pre-amp circuit we built in class. Let me know if you wish me to send you details.

    I want external am/fm/weather radio as a backup just incase the computer kicks the bucket or something. Since the HU will only have a small LCD screen tuning, volume, and maybe some preset buttons I can also integrate some hotbuttuns for the computer, possibly a female 2.5mm(headphone size i believe?) jack for friends to plug in ipods etc...

    Great forum, just want to say hi to everyone.
    I'm not sure of normal hu outputs, but I know it's a lot stronger signal than 2.2v. 5v is a guesstimate.

    Here's the amp I was working on.


    I'm eventually going with a usb fm radio or the one that's being made by a member of these boards for completeness. I usually don't listen to fm but would like the option.

  10. #10
    MySQL Error scott_fx's Avatar
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    Quote Originally Posted by shotgunefx
    Damn! Beautiful car and install.

    Well, the amp I'm working on, it almost works too noisy. Based on LM386's. I think the problem is construction. If I can find one of these locally, I might just say hell with it and buy it as I'd much rather work on other aspects of the install this weekend. Though I like the idea of being able to 1. Limit the maximum volume in case the pc goes screwy (the sirius is going to go to the pc, which will then drive the amp) and 2, having a nice volume control on the dash. Especially at the moment as I keep yanking everything in and out all the time.

    thank you for the compliment. there is no standard as far as output voltage of h/u. when i first started putting systems in my car 2volts was the norm, now the norm seems to be 5volts and soon, as with a lot of eclipse units 8 volts is on the way. if you go into pro audio studios they'll go even higher then that with balanced signals.

    how this benifits you is that you can turn down your gain on the amp to reduce the amount of noise that will be amplified and introduced into your system
    New System in progress:
    M10k
    Phaze TD1500 ~> Dynaudio MD130
    Phaze TD1500 ~> Seas g18rnx/p
    Zapco Ref 500.1 ~ 12" tc-9
    Behringer DCX2496 ~ Envision Electronics psu
    Transflective Xenarc

    My Car Pc Install
    My Boat Pc worklog

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