What's new

Tianfeng

Beginner
Joined
Jan 7, 2019
Messages
3
Reaction score
2
Location
Canada
I used the search function but I was unable to find a clear answer. How is amplified audio mono and stereo, fed of the Jamma edge?

General all agree that pin 10 is mono but for stereo is is L or pin 11 or both depending on the boards?

Also what is the proper attenuation circuit for the audio. I saw some simple things like a 10k resistor in series with a 1k voltage divider and more complex thinks like 880ohm in series to a 47uf cap and 20k on the output.

I am pretty new to this stuff so any help is appreciated.
 
Most boards which are capable of stereo have an additional header for it which can be line level or amplified.
There are only some exceptions like NeoGeo MVS which have stereo on the Jamma edge (but then it is no longer called Jamma, but MVS pinout), There pin L is L+ and Pin 10 is R+)

Here is a list of most stereo board known and as you can see most have stereo either on an additional header or directly via RCA plugs;
List of arcade PCBs with stereo output
 
Thanks for that. So nothing uses pin 11? Is there a particular attenuation that people prefer to use?
 
So you wire the Jamma harness to the line level convertor then from the rca out to a seperate amp and speaker combo? Do you often swap boards on that setup? Do you have much fiddling to mainting audio levels?

Being a beginner I was also wondering about audio options.
 
So you wire the Jamma harness to the line level convertor then from the rca out to a seperate amp and speaker combo? Do you often swap boards on that setup? Do you have much fiddling to mainting audio levels?

Being a beginner I was also wondering about audio options.
Correct, and yes I swap boards a lot, but as most Jamma boards have volume control it is not hard to keep a steady volume.
 
I am reviving the thread, because I have some unanswered questions about JAMMA audio:

1. I am still unsure about pins L & 10 and M & 11.
Some people say that L & 10 are post-amp and M & 11 pre-amp (that would be more accurate to the standard), but others say that for stereo from JAMMA, L & 10 are left speaker and M & 11 are right speaker (which would be more of a hack and not that much standard, then).
So, are both views right, ie. it depends on the JAMMA board, or is there only one right answer?

2. I see many superguns having a stereo switch.
How is that wired and what is the purpose of that? Is that a MVS only thing or is there a more extended purpose?
 
Some people say that L & 10 are post-amp and M & 11 pre-amp
That is correct according to the JAMMA standard, however I can't think of a single JAMMA board I've ever seen that provides pre-amp audio on these pins.
others say that for stereo from JAMMA, L & 10 are left speaker and M & 11 are right speaker
Maybe some boards do this? but it's certainly not any sort of standard, and I would recommend against wiring any cab or supergun setup this way unless you were dedicating it to a single PCB where you'd already confirmed that's how it's wired.
are both views right, ie. it depends on the JAMMA board, or is there only one right answer?
I would say that NEITHER view is right.

Honestly expect amplified MONO audio from the L&10 Pins on the JAMMA edge and thats it. If you want stereo have your setup able to switch to unamplified RCA inputs and plug those directly into the PCBs that support it (like CPS2, CPS3, NAOMI, System 12, etc.)

for everything else that has an amplified stereo header (like a lot of Konami and Taito boards) build an appropriate adapter/converter to change that to line level RCA.
 
Last edited:
Thank you for your answer.

For the L & 10 as left speaker and M & 11 as right speaker, some boards do that, so it actually exists. But on a second thought and after more research, I believe it is indeed NOT standard.

But saying neither are right, why not, but on what basis are you saying that? I need more information.

Also, stil looking for an answer about question 2:

Braintrash' said:
2. I see many superguns having a stereo switch.
How is that wired and what is the purpose of that? Is that a MVS only thing or is there a more extended purpose
 
But saying neither are right, why not, but on what basis are you saying that? I need more information.
I'm saying that because:
I can't think of a single JAMMA board I've ever seen that provides pre-amp audio on these pins.
and
Maybe some boards do this? but it's certainly not any sort of standard
The whole point of a supergun is to build something that simplifies the process of hooking up many different arcade boards. Designing it around obscure standards that almost no boards support isn't going to get you there.
 
Yes, Battletoads. As I said, some boards do that and Battletoads is the one coming on mind. A more thorough search will be needed for that, but since at least one "official" board do that, then that's a thing and, as such, we can't say for sure neither answers are wrong.
I believe the first one (pre-amp/post-amp) should be right, then, although, more a hack than standard?

Anyway, that's enough for me at this point of question 1: I know what to look for, so I'll get to the bottom of that.

Remains question 2: how is the stereo wired on superguns? Is is something dealing with MVS or something more?
 
Back
Top