Stereo sound from jamma harness?

Ghostnuke

Well-known member
Joined
Jul 3, 2010
Messages
4,168
Reaction score
399
Location
Lawrence, Kansas
I am doing my very first wiring job on a cabinet I picked up. I'd like to wire it for jamma, but I would also like it to have stereo sound. Is there any way I can do this?

I know a standard 56 pin jamma harness only outputs mono sound, is there any way I can use some of the unused slots for an extra speaker?
 
I am doing my very first wiring job on a cabinet I picked up. I'd like to wire it for jamma, but I would also like it to have stereo sound. Is there any way I can do this?

I know a standard 56 pin jamma harness only outputs mono sound, is there any way I can use some of the unused slots for an extra speaker?

http://groups.google.com/group/rec....g/browse_thread/thread/221595d2af6f1c81?pli=1

Ken Layton said:
JAMMA stereo speakers are as follows:
Pin 10 (parts side) is left speaker +
Pin L (solder side) is left speaker -
Pin 11 (parts side) is right speaker +
Pin M (solder side) is right speaker -
JAMMA mono speaker is as follows:
Pin 10 (parts side) is speaker +
Pin L (solder side) is speaker -
The above connections are to go directly to a speaker. Do not mess
with any grounds.
 
Or in Neo Geo MVS land, the Speaker - is actually connected to common ground and Left Speaker + is Jamma L, Right Speaker + is Jamma 10.

You can build a switch between the two as-follows (not my graphic, shamelessly stolen from Neo-Geo.com forums).

mvsjammaswitchbo6.jpg
 
A neo geo single slot was what I was wanting to use...

Can I use Ken's method or do I need to make the switch thingy? Does anyone sell them pre-built? I have to confess I don't really understand the diagram.
 
A neo geo single slot was what I was wanting to use...

Can I use Ken's method or do I need to make the switch thingy? Does anyone sell them pre-built? I have to confess I don't really understand the diagram.

Being the owner of a Neo Geo single slot, I can tell you that it's JAMMA, and not the slightly odd JAMMA off-shoot that Neo Geo is normally related to (IE: the previous example). So it should.
 
Being the owner of a Neo Geo single slot, I can tell you that it's JAMMA, and not the slightly odd JAMMA off-shoot that Neo Geo is normally related to (IE: the previous example). So it should.

So I can use Ken's method then? Would you mind if I PM you another question I have about running a single slot?
 
Ok so after reading a bit on the neo geo forums, it looks like I need to build the thing in the diagram. They said I need a 3PDT switch (whatever that is) to make it.

Can anyone walk me through this in layman's terms? Maybe with pictures or links or something? I'm pretty thoroughly confused.
 
Suprised no one has pointed out that Stereo sound is determined by the JAMMA board, not the wiring to the speakers. If you hook your speakers up in stereo mode (wiring to both 10/11 and L/M), and you connect a JAMMA board that outputs mono sound only, you'll only get sound out of one speaker. I will not be stereo. If you want sound out of both speakers, you'd have to connect the mono output to both speakers, but then you'd just have the same sound out of both, and still no stereo sound.

Only JAMMA boards with stereo output will give you stereo sound...
 
Suprised no one has pointed out that Stereo sound is determined by the JAMMA board, not the wiring to the speakers. If you hook your speakers up in stereo mode (wiring to both 10/11 and L/M), and you connect a JAMMA board that outputs mono sound only, you'll only get sound out of one speaker. I will not be stereo. If you want sound out of both speakers, you'd have to connect the mono output to both speakers, but then you'd just have the same sound out of both, and still no stereo sound.

Only JAMMA boards with stereo output will give you stereo sound...

That's a good point. From what research I've done, most JAMMA boards are mono anyway. I suppose the only reason I really want to have stereo is for the Neo Geo games that have it, and I think it would be nice to have mono sound from two speakers. Just so you get sound from both sides.

Isn't that the purpose of the switch however? Red and black together would give you mono sound when there's a JAMMA board hooked up, and then black to green would give you stereo when you have your Neo Geo board in there. Am I correct?
 
If you wire the cab for stereo sound from a Neo Geo MVS board then plug in a JAMMA board you will fry the audio amp chip on the JAMMA board.

You MUST either use a switch and wire it as shown OR buy a JAMMA adapter to plug a JAMMA board into the MVS wired cab.

Neo Geo Stereo wired board > JAMMA cab = works, but only one channel of audio.

Neo Geo Stereo wired board > MVS cab = works, with stereo audio

JAMMA mono board > MVS cab = fried audio output IC.

JAMMA mono board > JAMMA to MVS adapter > MVS cab = works with mono audio over the speakers.

Note that NOT all 1 slot boards are stereo. The ONLY stereo MVS 1 slot boards are the ones with the Mono/Stereo selector switch. ALL others are JAMMA mono.

ALL of the 2, 4, and 6 slot boards are MVS Stereo ONLY and are NOT switchable to mono.
 
If you wire the cab for stereo sound from a Neo Geo MVS board then plug in a JAMMA board you will fry the audio amp chip on the JAMMA board.

You MUST either use a switch and wire it as shown OR buy a JAMMA adapter to plug a JAMMA board into the MVS wired cab.

Neo Geo Stereo wired board > JAMMA cab = works, but only one channel of audio.

Neo Geo Stereo wired board > MVS cab = works, with stereo audio

JAMMA mono board > MVS cab = fried audio output IC.

JAMMA mono board > JAMMA to MVS adapter > MVS cab = works with mono audio over the speakers.

Note that NOT all 1 slot boards are stereo. The ONLY stereo MVS 1 slot boards are the ones with the Mono/Stereo selector switch. ALL others are JAMMA mono.

ALL of the 2, 4, and 6 slot boards are MVS Stereo ONLY and are NOT switchable to mono.

Ok, I think I've got the hang of wiring things for stereo then. One last question regarding mono however:

If I used Ken's previously mentioned method of using pin 10 to a second speaker's + and pin L to a second speaker's -, this would create a system of two speakers both outputting the same mono channel. Would this system work for both JAMMA and a single slot Neo Geo without frying anything and without the need for a switch?
 
No. Some systems are bridged outputs and won't work that way.
 
Holy shit, just had an epiphany. A stupid one, but might save me some work.

It seems like it would be a lot easier to just wire the cabinet as an MVS and then use an adaptor to play JAMMA games.

That way everything is wired up for stereo sound without the need for switches and the possibility of frying anything.

Goddamn I'm dumb, hahaha. I guess sometimes you just have to leave and come back with a fresh perspective.
 
this may be a stupid question and I apologize for re-opening it.....If I have a cabinet with a jamma harness that is mono (MK2 cabinet) and I have a jamma board that outputs Stereo...If I just want Mono (don't ask me why) will this work just fine once I plug it in without touching any wiring? I simply want to leave the wiring and sound as is, just don't want the mono speaker to blow or anything.
 
Depends on the board. Most systems output stereo sound via a header or RCA jacks, unfortunately the multi slot MVS boards output stereo via the JAMMA connector and on a cab wired for mono you will have left + on one side of the speaker and right + on the other. As a result the voltage across the speaker will only be the difference of the two channels.
 
Back
Top Bottom