MagicianLord77
Enthusiast
Hi guys,
I have a MV-1B Neo Geo MVS board, and I wasn't satisfied knowing that the games have stereo audio but this board can't output it, so I started researching about stereo line-out mods.
Found that there is a very basic one and a better one, so I went for the latter, the "MKL" mod:
So I went and soldered a piece of perfboard that had from a previous failed circuit (that's why it's missing some pads). The audio jack is a PJ-307, fits pretty well.
Placed it over where it doesn't disturb with a hot-silicone gun:
From there I run a 3.5mm male to 3.5mm male cable to one of those TDA7266 / TDA7297 Amp chinese boards (planning to do my own amp in the future), and from there to the stereo Aero City speakers and that's it, stereo amplified neo-geo sound
.
---
I recorded some audio from Metal Slug X just to post here how does the mod sound:
Stereo mod: https://www.sndup.net/5gv7/d
When recording it, found that the waveform looks kind of cut at the -0.5 range, I recorded the same sound from MAME (using the nice -wavwrite parameter):
MAME: https://www.sndup.net/39qx/d
And found the audio should be more symmetrical, I mean, the negative portion of the waveform is clearly cut, happens with other games too, does any audio expert there knows the name of this issue? too much grounding of the signal? Appreciate any opinion of this matter. In the end, to my ears it sounds the same, but I'd really like to understand what's happening.. From my ignorance, I believe the resistors should have different values for this issue to disappear, right? Thanks!
I have a MV-1B Neo Geo MVS board, and I wasn't satisfied knowing that the games have stereo audio but this board can't output it, so I started researching about stereo line-out mods.
Found that there is a very basic one and a better one, so I went for the latter, the "MKL" mod:
So I went and soldered a piece of perfboard that had from a previous failed circuit (that's why it's missing some pads). The audio jack is a PJ-307, fits pretty well.
Placed it over where it doesn't disturb with a hot-silicone gun:
From there I run a 3.5mm male to 3.5mm male cable to one of those TDA7266 / TDA7297 Amp chinese boards (planning to do my own amp in the future), and from there to the stereo Aero City speakers and that's it, stereo amplified neo-geo sound
.---
I recorded some audio from Metal Slug X just to post here how does the mod sound:
Stereo mod: https://www.sndup.net/5gv7/d
When recording it, found that the waveform looks kind of cut at the -0.5 range, I recorded the same sound from MAME (using the nice -wavwrite parameter):
MAME: https://www.sndup.net/39qx/d
And found the audio should be more symmetrical, I mean, the negative portion of the waveform is clearly cut, happens with other games too, does any audio expert there knows the name of this issue? too much grounding of the signal? Appreciate any opinion of this matter. In the end, to my ears it sounds the same, but I'd really like to understand what's happening.. From my ignorance, I believe the resistors should have different values for this issue to disappear, right? Thanks!
