Values are the same as native (they're written on the caps) I replaced them just in case. I'm not sure about pro sound since this was a gaming gameboy.

If you want to avoid hum I suggest using this approach http://chipmusic.org/forums/topic/6031/ … -mount-ic/

In one of my other projects I used DIP inverter, but managed to allocate it right above the LCD jack and in such position there's no hum at all. If you're using ThursdayCustoms's biversion kit you're fine as well

The hum appears when your inverter is somewhere in the region of GB processor on the link port half of the board. That's what trial and error shows.

Aha, this is very helpful! Thanks!

friendofmegaman wrote:

Apart from the aforementioned points I also replaced a cap on the power regulator with new (and bigger) one and replaced both caps on the phone jack PCB. And I have no hum at all.

I will probably do this mod in a near future, would you mind telling which cap did you replace and with which value?

Also, does this hum issue concerns only the regular mini jack output or also Pro mod sound output as well?

Thanks!

Values are the same as native (they're written on the caps) I replaced them just in case. I'm not sure about pro sound since this was a gaming gameboy.

If you want to avoid hum I suggest using this approach http://chipmusic.org/forums/topic/6031/ … -mount-ic/

In one of my other projects I used DIP inverter, but managed to allocate it right above the LCD jack and in such position there's no hum at all. If you're using ThursdayCustoms's biversion kit you're fine as well

The hum appears when your inverter is somewhere in the region of GB processor on the link port half of the board. That's what trial and error shows.

Apart from the aforementioned points I also replaced a cap on the power regulator with new (and bigger) one and replaced both caps on the phone jack PCB. And I have no hum at all.

I will probably do this mod in a near future, would you mind telling which cap did you replace and with which value?

Also, does this hum issue concerns only the regular mini jack output or also Pro mod sound output as well?

Thanks!

Apart from the aforementioned points I also replaced a cap on the power regulator with new (and bigger) one and replaced both caps on the phone jack PCB. And I have no hum at all.

Of course it was a 'mechanical' solution. I don't know the real cause of the hum and so have no clue how to address it by the book.

Hmm. Yeah. I noticed a hum too. So far only installed two successful backlight mods but one of them has a clearly louder hum emitting from the internal speaker.
Not that that really matters, it just purrs like a little machine kitten.

I could only expect that it's a little like what happens to computers where there this thing: like if you have a sound cable thingy hanging too close a graphics card or something pressure on the graphics card can actually be heard through speakers or headphones. Very common "problem". ???

I wouldn't have minded if it were a nice hum, but it was a high-pitched whine.  I ended up swapping the LCD board with another one instead of bridging and grounding the biversion chip.  This one is so much quieter.

I could only expect that it's a little like what happens to computers where there this thing: like if you have a sound cable thingy hanging too close a graphics card or something pressure on the graphics card can actually be heard through speakers or headphones. Very common "problem". ???

Not sure if the hum appeared after I did the mods or was already there. I couldn't figure out what it was that did it but I did notice it's only in one of the jacks.

But doesn't LSDJ have a invert option built in now?

It does, but maybe they want to play other stuff inverted or whatever.

more contrast for more hum doesn't seem like a good trade off.

That's not what's supposed to happen.

Edit: From my limited knowledge on the subject, this sounds reasonable. I know I always get extra whine and hum with my guitar gear when there's a grounding issue.