Ok, I’m building a supergun for my cps2 ssft2. Everything was working great until I wanted to get the mono audio off the jamma edge connector. I hooked up the speaker + and - off the jamma edge directly to an RCA phono plug. When i hooked the rca to my TV it fried the A-board sound. Not a big deal as i just replaced the a-board. I’m guessing taking the + - speaker connectors directly to phono plug was a bad idea? What is the proper way to do this?
are you sure you were using the + and - from the board, it should be fine, though why not just take the stereo from the jacks it already has? much better sound anyways. The stereo jacks on the board are not amped so the volume would be adjusted by the TV rather than having to mess with the volume buttons on the board itself when using the jamma edge.
You absolutely positively should not connect an already amplified audio source to line-in! You must pass the signal through a simple attenuation circuit first or bad things can and will happen. Though as already mentioned it does seem kind of pointless if all you’re looking to play is CPS2 which has RCA stereo audio output out of the box.
The problem is that speaker- (jamma pin L) must NOT be used as it’s not ground while the audio negative on your TV/stereo receiver needs to be grounded. So you just have to use a ground instead of speaker- which should only be used when connecting directly to a speaker (as in cabs). Of course an attenuation circuit isn’t a bad idea if you know how to do it (most people don’t and use a circuit that causes issues with a number of board).
Thanks guys… So I need to hook the + to center pin on rca and a jamma ground to the outside rca, while not connecting the - speaker at all ? What would be the benefit of using a attenuation circuit over the above method?
oh, this will used with other games besides cps2 which is why I’m doing this.
Not kill your TV’s speakers and/or amplifier should you accidentally set the volume too high…?
Ok, Can I go buy this device at radio shack? Is it difficult to wire up?
Exactly.
The attenuation circuit is something you can add but the above (ground as neg and not using jamma L) remains correct.
I would advise not to use the attenuation circuit in the above link as it’s reported not to work with all boards (e.g. the most recent Cave games, etc.). I would suggest the circuit on the Sanwa converter VC-J which doesn’t seem to suffer from the same problems:
http://img229.imageshack.us/img229/6005/vcjgw6.jpg
Here’s a pic of the circuit on a supergun I’ve recently built, if it helps:
Umm, can’t really make much out of those images. One resistor was replaced with a potentiometer and two additional capacitors were somehow added…? Care to draw up a wiring diagram perhaps? :wgrin:
It’s there, scroll to the right.
Doh, too small browser window! 
Thanks!
oops, I use the + and ground, for some reason I was thinking the - was ground, sorry about that. The attenuation circuit is a great and safe way to do it. I never had a problem without it, knock on wood, but like I said just for the CPS2 just use the stereo jacks already there and make sure to change it in the sound settings for the board to get the Q-sound stereo mode.
MKL, always knowledgeable and always beautiful work, how do you do it? I needs teh secrets. :wgrin:
While we are sort of on the subject…
In order to record the local 3S ranbats I’m putting together a simple device consisting of the above attenuation circuit and a JROK encoder wired to a back-to-back JAMMA fingerboard/edge connector combo. Naturally the recording has to happen while the game is still displayed on the arcade monitors, so is it enough just straight up split the audio/video connections or could this cause any interference? Would it be a good idea to add say diodes or something to keep the recording device and cabinet monitor/speakers separated?
If the jrok is the newer version with component, splitting the video lines will not work. If it’s the older version with only composite and s-video out it should work fine. Note that the sanwa converter, based on a Fujitsu MB3516 encoder (100% compatible with the Sony CXA1645), splits the sync line via inverters on the 74HC14. Other than that there is nothing particular done to the RGB lines.
http://img522.imageshack.us/img522/2804/sanwaconverter2if1.jpg
Ahh, right. My JROK is a v4.1 (with component output) so then I should use the RGB passthrough header in order to safely feed the video back to the cabinet monitor?
What about the amplified mono sound, can that just be splitted with one wire going to the cabinet speakers and the other to the attenuation circuit? And if I wish to provide both a left and a right channel (with the very same audio in both) I could just split the signal after the attenuation circuit?
Thanks!
That’s a “TV-friendly” RGB output (0.7vpp) though and is not ideal for an arcade monitor. I can’t guarantee it will work and if it does the picture might be dim. It’s not the best way to do it but I don’t see better alternatives at the moment.
Yes.
Yes.
I have the JORK component video converter and it does not allow you to run the TV out and the arcade monitor simultainously.The monitor picture becomes very dim. Maybe there some way to boost the rgb signal?
So no (easy at least) way to use a a JROK v4.1 for recording video while simultaneously being played on an arcade monitor? Bummer.
Also have a NeoBitz-S encoder available to me, can I just split the video lines to one of those? Though from what I’ve read it has piss poor compatibility with anything aside from Neo-Geo hardware. Maybe I should just get a JROK v3.1 instead…
Good news for you. Today I ran some tests and splitting the RGB is fine if you use the composite output (and likely also s-video and component which I haven’t tried though). The issue I mentioned above is only with the RGB output of the jrok and I’m not yet sure why it happens* since the RGB out (that I added myself) of the VC-J (as well as that of other encoders) works fine.
*Probably using composite instead of sync will fix this.