Monday, June 20, 2011

Mini guitar amplifier

[EDIT: also check out TDA7052 portable speaker for MP3 players I made.]

I've been building this circuit again and again since 2006, when I first built it.

It's an extremely simple mini amplifier. It has a single TDA7052 amplifier IC, a couple capacitors and one resistor... The circuit is designed and documented by RED free circuit designs. The TDA7052 datasheet also shows a very similar application example.

There's no volume control. You can use your guitar's volume knob. With full volume, there's usually some distortion, especially when the battery starts to drain up. But the distortion actually sounds pretty cool.

I've used this thing also as a speaker for my MP3 player. I just wired the left channel to the input of this thing. Works fine, but don't expect much from the sound quality...

My first amplifier build looks like this.

I had found some very cool old telephone routing / answering machines from Philips and decided to use one as the case. They're wooden and feature some very cryptic buttons...

Neat case!

You can see there's plenty of room left in the case... Note also the old film container I used as the battery holder.

The downside with the case is that it's far from airtight and doesn't give the best bass response.

Once a friend tried to use a wall wart to power one of these. He got the polarity wrong and blew the TDA7052, leaving a crater in the chip. I was called to the rescue. I had luckily used an IC socket, so I could replace the chip without any soldering.

Poor TDA7052...

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