Custom “Pro Sound” Game Boys

my first two custom Game Boys, BUDO (left) and MIKAN (right)
My first two custom Game Boys, BUDO (left) and MIKAN (right)

Since the winter break, I’ve been tinkering around with some chiptune projects, and I’ve got quite caught up in the simultaneous progressive and regressive sound design of composing with chips of the 1980s and 90s. Perhaps its a stretch, but I believe this kind of cultural re-appropriation as directly akin to drawing influences from outside Western Music.

Philosophy aside for the moment, as my first gaming system was the original Game Boy, I’m particularly interested in the circuit-bending and customization artists are doing with these old devices, so I’ve been getting my hands dirty for the last couple of months customizing these two Game Boys that I picked up on Craigslist.

While a lot of the work was purely cosmetic, I did a “Pro Sound” mod on both of them, which basically is just bypassing the internal (noisy) headphone amplifier and putting in some RCA jacks. On the Game Boy Color here, I also bypassed the existing audio output capacitors with some bigger ones, which supposedly gives a bass boost. While I hope to do some more experimenting in the future, most of what I did to these two units was a matter of just following instructions.

I’m calling the original Game Boy “MIKAN.” Customizations:

  • Orange screen backlight
  • “Pro Sound” RCA Mod
  • Custom buttons, ON/OFF switch, screen lens, link cover, orange LED, and battery cover

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The Game Boy Color, “BUDO,” has:

  • Green LED
  • Original (broken) speaker replaced with Nintendo DS speaker
  • “Pro Sound” with bass boost capacitors to RCA outs
  • “Anti-noise” decoupling capacitor

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They both have their own peculiarities in terms of sound. BUDO has some sub-audio in its output (perhaps a result of the bass boost), and MIKAN, without a decoupling capacitor, sometimes has “clicks” at the start of sounds (perhaps related to the DC power somehow). I’ll post some sound samples as I keep working on my current project.

I have to say it’s really fun and rewarding to do these customizations. While I’m working on a piece now that uses these “instruments,” I’m also trolling Craigslist for another cheap Game Boy so I can do the customizations again (and try some new things).

Of course, lest I give the impression that I’m the first one to be playing with the ideas in the realm of concert art music, check out this fantastic piece by Matthew Joseph Payne, performed by Meerenai Shim, flight of the bleeper bird.

SN76489 Chip-Based Synthesizer

Over the break, I took some time to put together an arduino-driven synth from this “instructable” by Brian Peters.

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Yeah, inside the radio case

This is a synthesizer made from four SN76489 chips. These chips appeared as a cheap audio solution in a number of old computers and game consoles, including the ColecoVision, NeoGeo Pocket, Sega Genesis (although the Genesis had another chip capable of FM Synthesis).

Because these chips are cheap, this ends up being the cheapest synth on my rack:

$19.00 – Teensy 2.0 Board
$4.50 – 4x SN76489AN Chips (includes shipping)
$1.30 – 1.8432 MHz Oscillator
$0.10 – 4x 75k Resistors
$0.10 (or so) – 4x 10µF Capacitors
$5.00 – 4x 1/4″ Audio Jacks (these were way too expensive on Sparkfun)
$5.00 – Breadboard

$45.00 – Total (give or take)

So, it’s been about 15 years since I bought it, but I think that’s even cheaper than my Alesis Nanobass (appears in the background of these photos).

Why did I put it inside and old radio? Because that was what I found a Goodwill for $2 that was an appropriate size.

The aptly named Arduino "Teensy"
The aptly named Arduino “Teensy”

Teensy, SN76489 chips, and quartz clock ready for wiring
Teensy, SN76489 chips, and quartz clock ready for wiring

The rats' nest
The rats’ nest

So what does it sound like? Here’s a quick and dirty demo:

RCA Output on a Super Game Boy

Always looking for an excuse to open something up
Always looking for an excuse to open something up

For my latest “chiptune” project, I’ve put in some RCA jacks on my Super Game Boy.

Of course the Super Nintendo already has the possibility of a component out (via RCA jacks), but, since the Super Game Boy basically contains all the circuitry of the Game Boy, this mod bypasses the Super Nintendo altogether.

If you’re interested in trying this yourself, check out this instructable for step-by-step instructions.

Super Game Boy guts
Super Game Boy guts

Testing...
Testing…

Closed back up
Closed back up

So… Does it sound better? I don’t really know, and I don’t really have the time to set up a comparison, but this mod sure makes it easier to get sound to my mixer.

Here are a couple quick recordings of games I had lying around:

Battletoads

[audio:http://www.simonhutchinson.com/BattleToads.mp3]

Ninja Gaiden

[audio:http://www.simonhutchinson.com/NinjaGaiden.mp3]

The thing I have to be careful of, though, is that the clock speed of the Super Game Boy (4.295 MHz) is 2.4% faster than the Game Boy (4.194 MHz). A minor change, certainly, but a significant one if I’m trying to keep my music in tune between different devices, and I’m switching between the SNES and a Game Boy.

…like the time I brought my NOPera to Germany, forgetting that Europeans don’t tune to A440.