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Confusion over MVS cabinets speaker wiring. "parallel" vs "series"

Kujako

Kujako

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Looking at adding a JAMMA board to my MVS-25-2 cabinet. There are a few adapter boards out there, but one thing that caught my eye was the JNX Big Red adapter which carries the warning "If your cabinet's audio wiring is setup as parallel, then this adapter will not work for you. It is meant for original MVS multi slot cabinets that have their speakers wired in series. Using this adapter in a parallel wired cabinet can damage the audio amp on the JAMMA board". This is causing me some confusion, as I didn't think the audio wiring was either parallel or series but distinct with dedicated L&R positive pins (L&10)sharing a common ground (28). Looking at the wiring diagram for my cabinet would seem to confirm this (see image). The other adapter I am aware of is the JAMMA-2-MVS from the alas no longer operating jammaboards dot com. It carries no such warning that I am aware of, but instead has connectors for wiring in stereo from the JAMMA board and a series of jumpers to enable or disable audio passthrough. I guess my concern is, what are the risks and does anyone know if I can just use the JAMMA-2-MVS without worrying about the audio?

OFm7rpG.png
 
I thought two speakers wired to an amp directly is considered “parallel”. Voltage across each is the same as the source voltage.
 
ekorz said:
I thought two speakers wired to an amp directly is considered “parallel”. Voltage across each is the same as the source voltage.
Click to expand...
I thought that parallel referred to two or more speakers with the same +/-, so multi speaker mono audio... it may be that the definition changes depending on the application, which is why I'm confused. I guess the simper question may be "if I use a JNX Big Red or jammaboards JAMMA-2-MVS in an unmodified MVS-25-2 cabinet, am I OK?".
 
the wiring gets more convoluted when you're talking about stereo wiring.

for instance some "series" stereo setups look like this:
ssrear.gif
 
twistedsymphony said:
the wiring gets more convoluted when you're talking about stereo wiring.

for instance some "series" stereo setups look like this:
ssrear.gif
Click to expand...
That would seem to be closer to what the MVS uses, but the common negative is run to the JAMMA ground pin 28. Since there is no "audio" negative on the MVS, I guess that could be called series. OK, that makes at least some sense to me. My assumption then is that I'm good to go with either of the JAMMA to MVS adapters from JNX or jamaboards.
 
CORRECTION NOTICE (11/11/2023)
The diagram I posted below came from the Super Neo 29 Candy manual, which is apparently a JAMMA version of the Super Neo 29.
I've since done more research and learned the various Neo 29 cab variants. My cab is a Super Neo 29 (non-Candy), and is wired for MVS.

1. Does the JNX Big Red adapter work in a Super Neo 29? (non-Candy)
2. Does anyone have experience using the JNX Big Red on the Super Neo 29?

Here's the wiring diagram from the manual that I found (https://nfgworld.com/files/SNK_Super_Neo_29_Candy_Manual_(English).pdf):

1699229090065.png


It seems like this is series stereo wiring. Does anyone know for certain?

What is the block of:

1234
- - - -
1234

below the speakers supposed to represent?
 
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bitkid said:
Does the JNX Big Red adapter work in a Neo Candy 29? Does anyone have experience using the JNX Big Red on the Neo Candy 29?

Here's the wiring diagram from the manual that I found (https://nfgworld.com/files/SNK_Super_Neo_29_Candy_Manual_(English).pdf):

1699229090065.png


It seems like this is series stereo wiring. Does anyone know for certain?

What is the block of:

1234
- - - -
1234

below the speakers supposed to represent?
Click to expand...

I think that's showing mono audio going to a wiring block with two speakers. I seem to recall that they are not out of the box wired for MVS with stereo sound.

Here's a higher quality manual scan, even if it is in Japanese...
https://web.archive.org/web/2019100...o29candy/downloads/SuperNeo29Candy-Manual.pdf

Also, no mater what the manual says check the actual wiring. Unless you know for sure what was running in it, it could be JAMMA, MVS or who knows what.
 
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It is currently wired up to run a 4-slot MVS board, which is the only PCB that has been in it since I acquired the cab ten years ago. I will definitely check the wiring prior to attempting to hook up a JAMMA board, one way or another.

So, is that diagram showing that it is MONO wired in SERIES?

Also, is it possible to change up the wiring to run the 4-slot MVS in STEREO, or would that require an additional amp or some other extra hardware?

It would be awesome if I could somehow wire it up to accommodate MVS and JAMMA boards, with the option to run such boards in STEREO if the board supports it (i.e. CPS-2/3 boards, which as I recall require an extra sound amp, at least that's how my old NAC cab was when I still had it).
 
bitkid said:
So, is that diagram showing that it is MONO wired in SERIES?
Click to expand...

I would call this parallel not series. One thing to be VERY carful about if you move to series for MVS (assuming it hasn't already be rewired) is the resistance. In series the resistance is doubled, while in parallel the resistance is decreased. I think you want four ohm speakers for MVS stereo and eight ohm for JAMMA wired in parallel.
1699279844242.png
 
I could never run a dedicated Neo cab in mono, even though so many cabs and 1-slot boards are setup for that.
 
Kujako said:
I would call this parallel not series.
Click to expand...
How can it be parallel if it only seems to have 2 wires from the edge connector? That's why I thought it was series.

In any case, thank you for the handy diagram and reminder about the resistance changes. I recall hearing that a long time ago but the reminder is helpful.
 
The wiring in that Super Neo 29 diagram is parallel mono. The little jumpers on the harness side of the 4 pin connector are equivalent to if it was home runs for each. That said, Super Neo and Neo Candy are different cabinets. If your cabinet has a multi slot in it already, and it sounds correct, chances are it's wired for MVS stereo.

Series is when a wire goes ONLY from speaker to speaker.

I think the confusion is that from the initial post series and parallel aren't entirely clear definitions for a stereo pair with a common terminal. For the Big Red/MVS Multi Slot wiring, they're neither series or parallel. They're just two single stereo speakers.
 
OK so I learned more about these Neo 29 cabs and have come to find out that the Super Neo 29 is the MVS variant, while the Super Neo 29 Candy is the JAMMA variant. I've only been able to find manuals for the Super Neo 29 Candy. As far as I can tell the wiki page for the Super Neo 29 on Arcade Otaku is incorrectly showing PDF manuals for the Super Neo 29 Candy, both for the English and Japanese versions: https://wiki.arcadeotaku.com/w/SNK_Super_Neo_29

Does anyone have the manual for the Super Neo 29 (non-Candy)?
 
bitkid said:
OK so I learned more about these Neo 29 cabs and have come to find out that the Super Neo 29 is the MVS variant, while the Super Neo 29 Candy is the JAMMA variant. I've only been able to find manuals for the Super Neo 29 Candy. As far as I can tell the wiki page for the Super Neo 29 on Arcade Otaku is incorrectly showing PDF manuals for the Super Neo 29 Candy, both for the English and Japanese versions: https://wiki.arcadeotaku.com/w/SNK_Super_Neo_29

Does anyone have the manual for the Super Neo 29 (non-Candy)?
Click to expand...

I've not found anything on a MVS wiring service manual. Even Arcade Otaku has it wrong, listing the wiring as MVS but the manuals they link to clearly show that you must put the Neo Geo board in mono audio mode.

https://wiki.arcadeotaku.com/w/SNK_Super_Neo_29

But at the end of the day, what's in the manual matters far less than what the cab is actually wired for. You're going to have to just look and measure to be sure.
 
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