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How do I use an old sound card as a standalone amp? Answered


I have this old ISA sound card from a Pentium II pc laying around, and I was hoping to use it as a standalone amplifier. So far I found that it has a decent analog amplifier chip (ST TEA2025). I tried giving it 5V and giving it audio in on the designated pins, but to no effect. But ideally I'd like to use the existing Line In connector, wire it directly to the amplifier chip, and get audio out from the Out connector.

I've only been able to find one user who managed to do this, but his documentation is minimal: http://www.murga-linux.com/puppy/viewtopic.php?p=798918&sid=09cd6eb96653ecf2c5d8fceef9d45600#798918 (mirror)

Hopefully anyone has some experience with this kind of project, or can give me some tips.

The datasheet is available here: https://app.box.com/s/yh8moprz7ootuywo3yh6

Thanks in advance for any help!

5 Replies

Wired_Mist (author)2014-12-30

Quite simply; You don't

I can appreciate your effort ! :)

If you REALLY want to reuse the Caps and the Audio Jack how much is it really worth to you?

By the time you MAY POSSIBLY Hack into it, A prefab breakout board, or even "ye old'e 1980's Boom Box," would be a more efficient solution.

You can buy a ready made kit for a few bucks at Sparkfun.com; it's even 1/4 the size !

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MaterialBall (author)Wired_Mist2015-02-03

I figured it out after spending quite some time tracing the PCB. it's almost too simple, and I'm glad I tried, since this will fit neatly into a nice housing.

Key was to change the jumper pins, so that it bypassed the digital chip. Then I wired the line-in pins directly to the jumper pins, which lead to the respective audio in pins for the TEA2025 chip. Power is supplied to the 'wave table pins', which were quite easy to map.

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Vyger (author)2014-12-26

I think this question has been asked before, or one like it.

One of the key things you are missing are the drivers which are supplied by the OS. Its the software that tells the card what to do.

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MaterialBall (author)Vyger2014-12-28

I know, that's why I don't want to use the digital chip in the centre. The IC surrounded by all the capacitor in the corner is just an off the shelve amplifier chip. Instead of desoldering it and building the entire circuitery, I was hoping to reuse the capacitors and audio jacks.

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rickharris (author)Vyger2014-12-26

Not at all easily.

much easier to build an IC based amp.

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