System 11&12 audio output questions for switcher

I'm considering using a riddled TV switcher to put Tekken 2, 3 & tag into my Namco cabinet. The cab uses the onboard amplified audio, using the left channel from Jamma pin 10 and the right channel from the kick harness pin 1.

The switcher works by using Jamma pin 10 for audio left and 11 for audio right. It also has a header for these pins which I can use to jump the right channel from the kick harness and carry it out. My question is if the right channel comes from the kick harness, then what is "Audio (+)" as labeled on the pinout from the manual used for? Is it a duplicate right channel?

I made a little easy audio mod a while back that will bypass the amplified audio on the system 11:

https://www.arcade-projects.com/threads/namco-system-11-audio-“mod”.20251/

You can also use the RCA audio jacks on the system 12 and get yourself a little inexpensive audio amp which would be a lot easier than dealing with the onboard audio amps and the 48 pin right channel audio out especially with the volume control.
What you can do is get one of riddletv’s audio switchers which he has for sale on his website.

The right channel on the system 11 and 12 is only present on the 48pin kick harness connector, I’m not sure if the right channel would also come off the jamma harnesses. But since pin 11 and M isn’t connected to anything/ not used, then there should be a header on the switcher where you can plug in the right channel wire if you want to use the onboard amps. Just make sure that the wires are present for pin 11/M on your JAMMA harness

The original JAMMA spec called for AMPLIFIED audio on Pins L and 10 and UNAMPLIFIED audio on Pins M and 11. but it's exceedingly rare that a game utilizes the un-amplified pins. In-fact the only company that I can think of that supports it is Psikyo.

Also just a reminder that "Speaker -" IS NOT GROUND. while in some cases it CAN be ground it is not guaranteed and you're going to have a bad time if you assume that it is ground on the wrong PCB. I know you didn't ask about this but I've seen plenty of people run into problems when futzing with audio wires and making this assumption.

Franco23444 said:

The right channel on the system 11 and 12 is only present on the 48pin kick harness connector, I’m not sure if the right channel would also come off the jamma harnesses. But since pin 11 and M isn’t connected to anything/ not used, then there should be a header on the switcher where you can plug in the right channel wire if you want to use the onboard amps. Just make sure that the wires are present for pin 11/M on your JAMMA harness

Click to expand...

twistedsymphony said:

The original JAMMA spec called for AMPLIFIED audio on Pins L and 10 and UNAMPLIFIED audio on Pins M and 11. but it's exceedingly rare that a game utilizes the un-amplified pins. In-fact the only company that I can think of that supports it is Psikyo.

Click to expand...

This was what I was looking for; the manual made me think that there was something there. Thank you!

This is what I’ve come up with. I’m having an odd issue where there’s no sound on startup. If I pull the right speaker output and turn it on I have left channel only. If I reconnect the right channel while powered it works in stereo. If I turn it off and on again it’s back to no audio. Any ideas?

Did a bit more investigation. Pulled out the setup and put it on the test bench. The cab in question is a Namco Soul Edge cab, which has pots inline to the speakers, so i wanted to sanity check it. So out of the cab I wired a spare speaker to the right channel directly off of the kick and both channels work fine as expected. Connected as shown, no sound on power up. If I remove the right channel on the input side, the left channel will work on startup, but obviously no right. If left on and the right channel is connected while the game is running, we have stereo. So I’m pretty sure this is wired correctly. as mentioned before, after switching games or powering off it returns to no sound. It is the same with the remote board as well.

Any help is appreciated.

Ok, some more stuff. Ive been running this with Tekken tag and Tekken 3. I tried a Tekken 2 board and it Works fine. So there might be a timing issue on system 12 vs 11 boards. I’m out of amplified stereo pcbs to try, but this is the only theory that seems to fit.

Solution from riddledtv: cover pin 11/m with electrical tape on the PCB. Something on the PCB doesn’t like seeing the the voltage there. Works perfectly now!