Another point is that the AES3-6 has its stereo output through the headphone port reversed. I was able to confirm this with comparison of the music from the same game on my MVS system. The simplistic solution would be to fix this at the scart cable end by swapping pins 2 & 4. However the console would still be incorrect when using headphones or other speakers, so its best to fix on the motherboard.
It's not always swapped as the newer release of the 3-6 had it swapped fixed from the factory. If you see the two crossing resistors on your 3-6 then it's been fixed already.
See the last picture here:
http://www.neo-geo.com/forums/showt...revision-3-4&p=4322743&viewfull=1#post4322743