Neo Geo MVS to AES adapter sound issue

Hello everyone,

I have just purchased a Neo Geo MVS to AES adapter (neo mvs adapter) from "japangameonline.com" and the sound is terrible. The games runs ok but they sounds like there are saturated, basically the music is all messed up. However, when I play a regular AES game there is no sound issue.

The console is a NEO-0 (jap) version with board rev. 3-6, the voltage specs are 8W (pro pow 3). I have tried with a 12v-1.2a, 9v 1.2a and 12v - 3a regulator with no success. Also I have cleaned both the cartridge and console cartridge port with 90% alcohol several times, again with no success...

Anyone have an idea about how to correct the sound issue ?

 

A few pictures of the hardware

 

Does this happen with multiple MVS carts? Maybe there is something wrong with the MVS cart if it's your only one. You could figure that out by running it on a MVS system or getting another MVS cart to try. If you've tried multiple legit MVS carts and they all have this issue then maybe the adapter is faulty somehow.

 

I have tried with 2 games, the 161 in 1 game cart and KOF 97, both MVS game of course. Unfortunately I don't a have an MVS supergun or consolized system. I am pretty sure the problem comes from the adapter, what do you think ?