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.

 

[Derick2k]

Slight update:

So I added an optional thumbwheel volume pot and an extension header.
Both are optional and can be used as follows:
1. If you dont need them, you can just bridge the pad and pass the audio straight through.
2. You can use just the thumbwheel pot to control CPS1 volume internally, I would use it as a set it and forget it and adjust the volume level to your liking for your setup
3. Use the extension header to route the audio lines and mount a volume pot of your choice somewhere on your case or outside of it.

 

[bagheera369]

So per my usual manner, asking a few questions.

CPS1 Multi currently has the audio adjustment for CPS1.5 sound via either the Jamma Mono, or the RCA Stereo
CPS1 "A" board has the audio adjustment for the CPS1 games via the Jamma Mono

This new pcb will combine CPS1 sound and CPS1.5 sound, both in stereo, and output both through the RCA jacks.
The kit will contain two pcbs, one to attach to the DS Multi itself, and one to attach to the "A" board, to bypass the new mod, and output CPS1 and CPS1.5 via Mono on the Jamma edge.



If all this is true, then my questions begin below.

Was there a reason this wasn't addressed in the development of the multi, so that the filter board could have contained this circuitry, including the volume pot and a bypass, and cases could have been made to accommodate?

Is there any way to tie this new volume control, back to the volume adjust that already exists on the DS Multi, in order to limit the now 3 volume pots this multi is using?

The CN5/Jamma Volume PCB will be installing a new pot, apparently, in order to connect the mod and the main pcb together. Is it possible to source a pot that is shaped the same as the existing CPS1 volume pot, so that those of us with LIONS3 cases do not need to 3dprint/order a new adjusment extension for our cases?

The statment that this will "Auto-switch" the stereo output source based on the Multi game that is run....will this require new Multi firmware updates, or does it work similar to the crystal mod?

Is it safe to assume all of the "auto-switch" functionality is bypassed, if the CN5 PCB has it's bypass set to "ON", and CPS1 and CPS1.5 will continue to output via the Jamma edge in that case, or once the QSound and voltage lines have been run to this new mod, that CPS1.5 will ONLY work via the RCA Jacks?

This is the 4th modification PCB for this multi (Spinner, Crystal, Kick/3p/4p combiner), how much is the cost estimate for this mod, and will it be the last mod PCB needed to finally have a "Complete" multi-kit, or are there other mods still in the works?



Please understand that with the above questions, I am not knocking the current mod design, or the improvements it offers, or being ungrateful for all the work that has been put into the DS Multi, but merely trying to ensure I have everything correct, that all concerns have been checked, and hopefully encourage more thought into any future multi's so that situations like this can be tackled at the multi-development stage, and not afterwards.