JAMMA = mono / Jamma+ =stereo?

[Vebbo]

Hi, "my first post" 3 weeks ago i bought an arcade cabinet. It was a X-Men 4 player cabinet from 1992. I think it is a JAMMA+ cabinet (it has the 2 extra 15 pins connectors for 3/4 player connection) from what i have read on BYOAC forums and on the rest of the www. It has 2 speakers and from the "Sound out" on the PCB board it's 4 wire's leaving. I know JAMMA is mono but is JAMMA+ stereo?

Also if JAMMA+ is stereo, will the J-PAC offers stereo?

I have a X-BOX connected to the J-PAC (ordered stuff from Ultimarc), but stupid me clicked on the wrong product when ordering. I ordered the XBOX to AV JPAC /speaker adaptor, i think i should have ordered the cable with a split so i could get stereo.

[Ken Layton]

Jamma was originally mono, but around 1990 Jamma was ammended to stereo. That doesn't mean every gameboard is stereo though. Jamma + may have stereo depending on the gameboard.

[krick]

Traditionally,

pin 10 was speaker+ and
pin L was speaker-
and pins 11 and M were both unused.

Later, it seems that some manufacturers started using 11 and M along with 10 and L to support stereo connections. I'm not sure if there is any standardization in this area however.  Some schemes had a common ground for both speakers, others had separate + and - connections.   

The J-PAC only supports  a mono audio connection (mono +/-) as far as I know.  If you want, you could probably use the two J-PAC connections for left and right audio and run a separate common ground as long as you modify your cabinet's wiring harness accordingly.

There really is no such thing as a JAMMA+ standard.  JAMMA+ just means that it supports a JAMMA connector *plus* addtional connections, usually for extra buttons or joysticks.

Most modern stereo boards probably just have direct audio connections on the board itself and bypass JAMMA altogether.

[CheffoJeffo]

Also if JAMMA+ is stereo, will the J-PAC offers stereo?

Perhaps more important is the fact that the JPac doesn't amplify the audio (at the end of the day, 2 feet of seperation hardly makes for great stereo, particularly for an unamplified signal).

I think you'll find that Andy recommends replacing the cabinet speakers with amplified PC speakers (far be it from me to seak for Andy, but I seem to recall advice like this at some point).

Cheers.

[krick]

Remember, the J-PAC is merely a way to connect PC output (sound and video) to a JAMMA harness and control panel input to a PC.

There's nothing stopping you from amplifiying the audio *before* you feed it to the J-PAC.   That's basically equivalent to a JAMMA board with an onboard audio amp.

[CheffoJeffo]

krick is absolutely right and the same technique is used for some boards, like Egg Venture, which do not have onboard audio amplification.

Having said that, I believe the "use PC speakers" advice (which I attributed to Andy) is solid advice for the newbie.

What about sound?

The JAMMA standard is for only one speaker, mono sound. This is one of the reasons the J-PAC does not contain a sound amp. Other reasons are:
There is no readily available 12V supply. Using the available 5V supply would not enough power.
Using a separate mains adaptor would create issues with local line cord types.

How do I wire for sound?

There are several easy ways to do this:
Use a sound card with an on-board amp. Either wire this to the speaker connectors on the J-PAC to use the cabinet speaker via the JAMMA connector or by-pass the J-PAC and wire directly to one or two speakers in the cabinet.
OR: Use a set of mains powered PC speakers. Either remove the speakers from their cases and mount in the cabinet or simply place inside the cabinet. This will give the advantage of power stereo sound.

If it were me, I would check to see if my cabinet was wired for stereo and, if it was, I would put an amplifier inline between the PC and the JPac (e.g. I would do exactly as krick suggests) But then, I need to do the same thing for a project I have in the queue with an Egg Venture board anyway, so there would be minimal additional effort.

The first thing for you to do, however, is definitely determine is your cabinet is wired stereo.

Cheers.

[Vebbo]

Geeees do i feel stupid (typical stupid Norwegian or maby this is a side effect of the bird flu or the E.coli bacteria, i don't know I'm not a doctor) After studying the cable i got from Ultimarc i found out that it has a mini jack attached, so stereo here i come. The cable that are pictured on Andy's site must be a prototype or maby he has changed it lately without changing the picture of it. Well now I'm trying to understand the massive wiring in my cabinet *puh* it's got a lot of wires.

Thanks for the answers tho, i know now that i can ask about anyting, but i will of course do a search first

Cheers