Cheap Amplifier Build

by Seán Walsh in Circuits > Audio

1081 Views, 16 Favorites, 0 Comments

Cheap Amplifier Build

57b4cbbd50e1b6bd0b000a53.jpeg

So I took apart an old car radio a while back, looked at the datasheet and made a small boombox for my shed (I have lead acid batteries charging from wind and solar so the chip was quite happy without regulation)

The radio had two separate chips in it and I was wondering what to do with it for a while now but then my girlfriend mentioned that she had speakers from a surround sound system (but no controller strangely enough) so sooner than dumping them, I made a second amplifier circuit and I'm just going to show the assembly here..

The Enclosure

57abb72fecdf32c0a4c5c2fa3363db32a27535de_hq.jpg

I cut the back out of an ABS enclosure so I could screw the chip onto the heatsink. As you can see the box is screwed straight onto the heatsink too.

The Circuit

98740bd397555220acda2d86f7e99fc1644bbaef_hq.jpg
5c7db4fe4e315b020c994870233c6001be836b30_hq.jpg

The amplifier chip is a TDA7375A, a quick look on the datasheet shows some example circuits for it so I picked the most suitable design and bought a few capacitors which I didn't readily have.

I also bought a step down buck converter as I'm powering it with an old chrapbook charger, which outputs more voltage than the chip can take. I did buy multiple at a time so the cost of one was minimal..

Somewhat Compact..

35bc1dd9e10270b763d133723678a777ecd2b2b2_hq.jpg
8517d9fd90281d5706b65caaf694c5306daf6b80_hq.jpg

I definitely could have done with a bigger case but I managed to squeeze it in anyways. Also there is thermal grease between the chip and the heatsink so it should last a good while before going thermonuclear ;)

And that's it! Sorry it's not a full instructable but I'm pretty sure anybody could do this if they looked at the datasheet, also if you can't find old car radios anywhere I'm fairly certain ebay would sell similar if not better chips (I say better as the two chips I pulled were out of a radio with a cassette player haha)