NeX
Offline
trash80 wrote:
NeX wrote:

i disagree i think the SP can have amazing results with a pro sound mod depending on the model. japanese 101 models being the best

I've had different results. the 101 has more noise by default without modding. I probed the 101 as well and the noise seemed to come from the cpu's output so I couldnt get the noise to go away. I should look up what exactly you did and try again. you just hooked it up from the conveniently available pads on the pcb right?

i took the two pads above the speaker, the ones that lead down the left hand side and are marked in the bottom left as LIN and RIN i then put two 220 ohm resistors on those pads and a 1k from the AGND pad. i was also thinking about changing the cap for a slightly bigger one.

but i found that the sound was a lot cleaner than on the 001 models, they have an amp chip the same as the GBA and that amp will ground out the sound coming in, so really the only way to get a good sound from the 001 would be to cut out the amp or cut the traces.

Analog
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Ciudad de méxico, MX

Nex, any posibility on the classic GBA front?

NeX
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Analog wrote:

Nex, any posibility on the classic GBA front?

not at the moment because i don't have any GBAs but if someone is willing to donate one, then i would do it for a little cash (i don't get much free time any more)

wedanced
Offline
San Francisco

i may have an extra lying around. would be interested in seeing it done. i can no longer solder due to shakey hands but i would like to see this.

NeX
Offline
wedanced wrote:

i may have an extra lying around. would be interested in seeing it done. i can no longer solder due to shakey hands but i would like to see this.

well if you are up for it let me know smile

wedanced
Offline
San Francisco

this guy apparently has a gba prosound mod

thursdaycustoms
Offline
Cleveland, OH

Open it up. Look next to the cart socket. There are 2 small resistors. Solder your left and right on the side of the resistors closest to the cart socket.
I might do a tut for this soon.
It's insanely simple like all pro-sound mods.

Analog
Offline
Ciudad de méxico, MX
justinthursday wrote:

Open it up. Look next to the cart socket. There are 2 small resistors. Solder your left and right on the side of the resistors closest to the cart socket.
I might do a tut for this soon.
It's insanely simple like all pro-sound mods.


the other day I was with the GBA opened, found the ground and try to search for audio output points on the PCB, perhaps i've missed this. others sound not that good. Nex said someting about cutting the traces of the headphone amplifier, i'll love to try this.

is there any schematics of the gba, to know where to look for?


cheers!

Last edited by Analog (Jun 4, 2011 5:01 pm)

Apeshit
Offline

I haven't found any schematics for the GBA, and the inverted silkscreening makes it really hard to follow the traces...

wedanced
Offline
San Francisco

let me crack open my old crashed gba and see what i was doing. I wasnt as knowledgeable then and so Maybe now i can figure it out.

wedanced
Offline
San Francisco

ok so i just looked up a bit of research and cracked open my gba.


Looked at the pin layout for the amp chip and traced the lines back to the r30 and r31 resistors. I believe this is what was discussed before.


It should be like this: r31 right and r30 left audio channels.
If you connect to these areas it should bypass the amp circuit.
As far as I can tell the amp comes before the volume pot which is the opposite of the older gameboy models (please correct me if i am wrong). so if you cut the 7 and 8 pins on the amp chip and then take from the resistors and send them to the right and left chanels of the volume pot then you will have an easy internal gba prosound mod. If you add a jack and you dont care about adjusting the volume then you can just ground that that random point i squared (i assume anyways) and go straight to the jack. if you want volume then route it thru the pot and on the other side of the pot route it to the jack. done and done.


jacks fit easy in the back. this is how i had it setup before i fried my gba those years ago.

so just to be clear, i havent tried this mod out yet myself. so try at your own risk.

Last edited by wedanced (Jun 5, 2011 9:34 am)

Analog
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Ciudad de méxico, MX

thanks a lot wedanced, i'm going yo give it a try, and see how it behaves...

wedanced
Offline
San Francisco

Let us know how it goes. Waiting on a new gba in the mail. Gonna try to do it and I will post my results with sound comparisons and what not. We will see how this goes.

Theta_Frost
Offline
Milwaukee, WI

I have a clear pink GBA kicking around.  If I have any time outside of finals this week I could solder that up.  Don't have any 2.x to give good sound comparisons though.  If there is interest I could take pics and make a mini tut-ish.

wedanced
Offline
San Francisco

So... I failed because of my hands.... It's up to u guys sad
It's a shame that I can figure out how to do mods now but I am no longer able to execute them...
Can't tell u how bummed that makes me.

Analog
Offline
Ciudad de méxico, MX

those resistors are very small,... i've succesfully killed both on my gba's PCB. FAIL.