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Saturday, October 13, 2012

Game Boy Color Loud Sound Mod

Update: new version available for order

Update: published schematics and pcb design files for Eagle and Gimp. Make your own pcb and respect the license =) Take a look:

Recently I've got used Game Boy Color and noticed lack of sound volume, it is barely audible. So I tear it down and pulled speaker out, it was all rusty.

 I had a speaker for Motorola L7/L6/L2/L71/K1-GSM/V8 on hands and soldered it in. So this is fixed sound. But it is still not loud at all, so low volume, I had to use my headphones instead. Oh and there is loud hiss noise, guess it's coming from power supply. I had to do something with it =)
I looked in my parts bin and spotted TPA2000D1 - a class-D mono amplifier from TI. It is 2W power rated with programmable gain and class-d is pretty efficiency means low power consumption.
After some time pcb was made.

I used schematics from datasheet but in the final version I changed 1uF bypass cap and other 1uF caps to 10uF and added 0.1uF. Also I had to change 120k resistor in oscillator circuit to 180k to keep frequency below 300 kHz, it was 330 kHz with 120k resistor.

Powered up ok first time wires connected and sound now is much louder even with gain of 6 dB but then I set it to 12 dB by moving one resistor to outrun any ambient noise. This is max before clipping I guess. Unfortunately noise hiss did not gone away and become even louder on high volume, so this is power supply. Game Boy Color is powered with two AA batteries. But it has switching step up power supply with 15V and 5V output, this makes noise because amp is powered from 5V. I had to add additional 470uF cap to 5V power rail to make noise go almost away, now it's barely audible on max volume.

Amplifier pcb moved over speaker and case closes nicely.

Amp barely visible inside. This Game Boy Color now definitely has Hi Fi sound =)