Audio cable mod - Please confirm if it does not work with stereo sound

[RealMFnG]

I don't want to bump a couple of older threads over here and here. Just want to confirm if stereo sound works with the audio cable mod. Seems like it shouldn't. But before I tear my hair out trying to solution it, can we confirm for the time being it only works with JAMMA audio?

It is totally fine if it doesn't work; stereo sound is more important. Just need to confirm if users are going for stereo sound, they will lose the cool audio cable mod effects is all. Not too terrible of a loss considering now we have the auto-reset feature.

 

[twistedsymphony]

I haven't tried it myself but supposedly ST-V supports stereo pre-amp output via CN24 with the following pinout:

1-Left
2-Ground
3-Right
4-Ground

Though, I'd hardly call utilizing originally supported hardware features a "mod" unless I'm misunderstanding your question.

If you're talking about the start and end .wave file playback from the multi-cart, then that is designed to tap into the Audio input of the amplifier chip, which is already down stream from the audio output on the CN24 port. I don't see any reason why you couldn't simply splice the Multi-cart audio wire into the output on the CN24 connector with a 10K resistor to get the sound effects to play out of one of the channels (http://www.epanorama.net/circuits/linemixer.html). If you want stereo output out of both channels you'll need to build some kind of isolation circuit (otherwise you'd convert the stereo pre-amp output into a mono pre-amp output in the process)

 

[RealMFnG]

I haven't tried it myself but supposedly ST-V supports stereo pre-amp output via CN24 with the following pinout:

1-Left
2-Ground
3-Right
4-Ground

Though, I'd hardly call utilizing originally supported hardware features a "mod" unless I'm misunderstanding your question.

So yeah, this part is a known. This isn't the mod.

If you're talking about the start and end .wave file playback from the multi-cart, then that is designed to tap into the Audio input of the amplifier chip, which is already down stream from the audio output on the CN24 port. I don't see any reason why you couldn't simply splice the Multi-cart audio wire into the output on the CN24 connector with a 10K resistor to get the sound effects to play out of one of the channels (epanorama.net/circuits/linemixer.html). If you want stereo output out of both channels you'll need to build some kind of isolation circuit (otherwise you'd convert the stereo pre-amp output into a mono pre-amp output in the process)

Don't need both JAMMA and and stereo audio. Just need one or the other. We already have the audio cable mod working with JAMMA as indicated here. Just need a mod so this works for stereo output. One channel is fine. Just need to hear the cues.


Anyhow, seems this mod only works with JAMMA audio. That is all that is needed to confirm now. Perhaps someone more skilled than me can make it work for stereo output. Not a deal breaker however, especially considering that we have the auto reset feature working now.

 

[RealMFnG]

So getting back to this. So if we use Mitsurugi's cable as the example, I would simply replace the 100ohm resistor with a 10kohm resister? I would keep the 1uf polarity neutral capacitor in place. Then instead of soldering to Pin 13 on the audio amp, just splice it into the L or R stereo output?

 

[twistedsymphony]

So getting back to this. So if we use Mitsurugi's cable as the example, I would simply replace the 100ohm resistor with a 10kohm resister? I would keep the 1uf polarity neutral capacitor in place. Then instead of soldering to Pin 13 on the audio amp, just splice it into the L or R stereo output?

Well, according to the schematic (which is also technically the same circuit Sega used on the model 3 mixer boards) you'd need to run the 10K resistor in line from both sources... meaning both the normal output from the ST-V and the Multi cart...

Honestly, it would probably work fine just running the wire straight to the connector without any resistors at all. Since that's what 99% of people tend to do when mixing audio anyway. I can't say for certain what works and what doesn't since I haven't played around with it.

Personally once I get the time to play around with my multi-cart setup even though mine is already modded for the normal amp connection I'm going to remove that and mount a small speaker/buzzer right on the cart itself since I want to be able to just pull and swap carts without worrying about additional wiring.

 

[RealMFnG]

Personally once I get the time to play around with my multi-cart setup even though mine is already modded for the normal amp connection I'm going to remove that and mount a small speaker/buzzer right on the cart itself since I want to be able to just pull and swap carts without worrying about additional wiring.

Well, it is somewhat unavoidable considering the auto-reset wire. Unless you go sans auto-reset wire, there will always be a cable connecting the cart to the mainboard.

I too was also thinking of a PC-case-type speaker for the audio cues. But it might be inaudible inside of a cabinet. Interested in seeing what you come up with. Also interested in seeing what 3D printed cart you come up with. My feedback for the 3D printed cart is that you leave room for:

1. The audio cable connection
2. The auto-reset wire connection
3. Remote board for jumper configuration

 

[RealMFnG]

Honestly, it would probably work fine just running the wire straight to the connector without any resistors at all. Since that's what 99% of people tend to do when mixing audio anyway. I can't say for certain what works and what doesn't since I haven't played around with it.

No need to run a ground wire off the cart?