Cps1.x Multi Audio Merge Discussion

[Mitsurugi-w]

Derick2k sent me a prototype of the audio merge kit and I installed it over the weekend. Install requires one to remove the two rca jacks off of the multi and install a pcb in their place. This pcb is powered via a 3 pin connector. You must tap 5v, ground, and the Dash signal from the multi to plug onto this connector. There is a cable used to tap line-level from the cps1 A board via the CN5 connector. This cable plugs directly from CN5 to a connector on the audio mod pcb.

The other part of making this work requires modding the A-board by removing the sound pot. CN5 does not output actual line-level unless the volume pot is removed. So to remedy this we remove the volume pot and install a small pcb that adds back the volume pot but with a bypass switch so we can choose whether we want jamma audio (bypassing the pot mutes jamma audio) or proper line-level. Note that doing the A-board mod is not required but I'd you don't you will have uneven channel volume and bad sound mixing.

One thing we may add is a volume control between CN5 and the audio pcb. Currently you can't control the volume from CN5 unless your cab has a volume pot. So some cabinets, such as q25, have super loud music because you can't lower it via the pcb.

Comments are appreciated. Pics below:

 

[mathewbeall]

What does this do? I read it a few times, and am not sure what audio its merging.

I know stock, both qsound and CPS1 games output via JAMMA just fine - I haven't checked but assume they output via the RCA jacks just fine as well?

Matt

 

[DRAGONKZ]

What does this do? I read it a few times, and am not sure what audio its merging.

I know stock, both qsound and CPS1 games output via JAMMA just fine - I haven't checked but assume they output via the RCA jacks just fine as well?

Matt

Normal CPS1 games only output sound over Jamma.

This solution is to allow people to use a single set of RCAs and both CPS1 and 1.5 will output over that.

Cabinets with Q sound amps (Gen 2 big blue for example) aren’t wired for jamma sound by default, so this mod “fixes” the issue of how to get sound for normal CPS1 games

 

[Derick2k]

This puts line-level audio at the RCA jacks on the multi as well as auto-switch the audio between CPS1 and CPS1.5 games based on the game loaded. Basically will work with any cab that has its own amp for audio.

 

[mathewbeall]

Got it - I only ever used JAMMA out - so didn't realize that CPS1 didn't also go out the RCA jacks.

Thanks!

 

[Jdurg]

Nice. Looking forward to this. It's the only reason my cabinet has been gutted and not put back together for the past four or five years. (Now I'm just hoping that my A-Board works. If it doesn't, I'll likely have to end up selling my multi-board since I can't just go out and get replacement A-Boards willy-nilly to try. Unlike many, I don't have a closet full of spare, confirmed working A-Boards I can use).

 

[kuze]

Looks great, very nice work. Love the bypass switch so you can still use JAMMA audio if/when needed too.

 

[Mechanos71]

My prayers have been answered! Can’t wait to install this and have some proper cps1 audio in my big blue

 

[Vinsanity]

Looking forward to this! Would favor inclusion of the on-board volume pot mentioned.

 

[Derick2k]

Thanks for the interest and feedback guys. I will do a few minor improvements and get it sent over to @Mitsurugi-w. Will probably do a small/limited run of these.