2PLAYER
Offline
Rhode Island

What you hear in the mp3 I posted was not altered. Captured as is with my computer and cropped together. I made a mistake in how I described the prosound/bass mod audio. I started that it was compressed when in actuality it was merely clipping. It was late. I was tired. I'll check to make sure my blog accurately captures what happened.

Also going to try to grab the audio from the points before the caps to see if this will give the same results as removing them. Then we can keep the headphone jack and simply rewire a prosound.

I'll grab some more audio tonight and post pics of the .wavs so you can visually see the difference

2PLAYER
Offline
Rhode Island

Okay, followed up with some more testing

http://2playermusic.tumblr.com/post/407 … io-testing

Domu
Offline
West Yorks, UK

glad to see your methodical reseach proces, thanks! im sure this will be help to people, it cant hurt to have some more well explored options.

+1 on the underclock crystal+ further research. keep it up! big_smile

wedanced
Offline
San Francisco

interesting. about to do a mod with my gameboys. this might be a neat inclusion to that project, along with the prosound and other shenanigans. dont want to say what i am doing yet but its safe that this should yield some interesting results with nothing other than just a game boy.

boomlinde
Offline
Sweden

How does the waveform look on the standard bass mod? To me it sounds like the pops could be from some kind of DC offset issue, which is not surprising if you start removing caps from things. Maybe you could just replace them with other caps.

2PLAYER
Offline
Rhode Island

That's very likely. I'll probably be heading by an electronics shop today as I am teaching a friend how to mod/solder. I'll pick up some different caps.

kineticturtle
Offline
Matthew Joseph Payne

Yeah, just experiment with lower values - less bass cut, rather than no bass cut (and a DC filter).

2PLAYER
Offline
Rhode Island

ya didnt get around to trying out different capacitors. however threw in a half speed switch.

http://2playermusic.tumblr.com/post/427 … eed-switch

The other half of 2PLAYER is borrowing a DMG of mine and my second cart so I wont be able to force the slowboy to run at the proper tempo but i will try to capture some of the audio tomorrow.

infradead
Offline
Tacoma WA

fuck yah

CV out from a gameboy!

spry
Offline
Cincinnati Ohio

have you guys done anything else with this?  ive just acquired a bunch of gameboys from the flea market and im gonna replace the capacitors in a couple of them.  i was thinking about trying smaller value on the audio filtering capacitors for maximal bass bumpage.  anyone have any experience or insights here?  i dont have a variable cap but im considering going out to get one for experimentating.

Trash80
Offline
Los Angeles

I have some insight, 3 years ago I replaced my caps for the same experiment http://www.flickr.com/photos/trash80/31 … 2041079668 ... Ened up using 1~2uf. Though Honestly the DC offset from the low frequencies is more trouble than its worth, you're better off just using a EQ after the cap rolls it off.

Also for anyone else, it's a bad idea to remove the caps altogether as its a buffer, at least, removing them AND doing a prosound mod. You can end up frying the cpu.

I don't know how I missed this thread until now.

xray303
Offline

interesting thread,

Regarding to the GB schematics, they are coupling caps, to remove the DC offset, so if you remove them, you will get a DC offset in the headphone op amp and it will sound like crap. it could be better to add bigger value ..

What could be interesting is to connect prosound cables directly before the 1uf caps .(or on the CPU himself) and add new capacitor between the other side of the cable and the 1/8 prosound jack. so theoretically you will get the sound quite untouched for the headphone and better bassy sound for the prosound output.
Will try this with different caps value (2.2 u to 10u) when i got some time .. (as they are decoupling caps, to get more bass you should put bigger caps)

Dragoon
Offline
Germany, Trier

i think, more uF just means more buffer size and more filtering...i have tried out 1uF (standard) up to 20uF caps.
no really soundincreasing. maybe if you went under 1uF to the range 0.1~0.9uF.
i would rather play with the resistors right beneath the caps!
but grabbing the sound of right the cpu...mhhh i must check that out.