Neo AES: Sound buzzes when screen turns white

Urbain03

Quiz Detective
Joined
May 24, 2004
Posts
83
I've got a strange problem with my Neo: there's an audible buzz in the sound when the colors on the screen are bright.

A good example: when the NEO-GEO logo spins at boot, the background changes from white to black. When the screen is completely white, the buzz is clearly audible... then as the background fades to black color, the buzz fade out too.

I can hear the buzz on the TV (i use a RGB cable), and even through the headphone jack when i hook the Neo to an amplifier. Oddly, the problem disappears when i use the headphone output with headphones.

The problem seems to be on the Neo since I use other consoles on the TV and amp without trouble (including a Genesis on which I use the same RGB cable)

I spoke to another Neo player who has the exact same problem.

Does anyone know if it is a common Neo issue ?

Thanks in advance for your tips ;)
 

SNKNostalgia

Beast Buster
Joined
Jul 11, 2005
Posts
2,117
This can be common with RGB connections sharing audio. I think there is a way to keep it from happening. Let me look up this site that says what you can do. I just gotta remember which of the 3 sites it is in.

***Might as well do a RCA stereo mod or just use the headphone jacks so you can get stereo sound. The AV port on the back is Mono only.***
 
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Urbain03

Quiz Detective
Joined
May 24, 2004
Posts
83
Thanks a lot for your link, but the problem isn't on the TV: i use other consoles ont the TV and i have no problem with them, including a Megadrive and a Master System which i use with the same RGB cable than the Neo.

I forgot to say that my Neo is stereo-modded with the classic Stereo Mod, and I can hear the buzz through them too ;)

I was thinking about one thing: does an audio-bypass mod exists for the Neo? I mean, like the RGB bypass but with audio instead... taking the audio signal directly from the chips to the AV port with a wire (maybe using some extra resistors or capacitors)... i think this could be helpful...?
 

Urbain03

Quiz Detective
Joined
May 24, 2004
Posts
83
It changes when i plug headphones on the Neo, but when I use the modded stereo output, the slider has no effect... in fact the stereo mod takes the audio signal just before it is processed by the headphone jack slider.
 

SNKNostalgia

Beast Buster
Joined
Jul 11, 2005
Posts
2,117
Hmm so thats not the problem then. Sometimes the amping use of the volume slider can be unfriendly to some stereo setups.

To tap into the audio comming off the chips you would have to do something similar to the MVS 1F stereo mod. I don't know the original points of the signals. You could just try to trace them the best you can, but can get tedious.
 

Urbain03

Quiz Detective
Joined
May 24, 2004
Posts
83
Thanks for the information, i'll try to find the plans of this MVS mod somewhere...

If anyone has some tips on how to do that, i'm interested ;)

I'm not the only person who has buzzes on AES sound, so it might be interesting :p
 
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