Using RCA jacks on a PCB

Is there any way to use RCA Jacks on a PCB? One of my cabs has speakers with RCA jacks, so they work great for CPS2 boards and such, but what if I have a standard JAMMA PCB like Killer Instinct?

I know that KI had a 'thing' with getting the sound to work as it states in the manual, but if the only speakers in the cab are connected to those RCA's what would be the best way to get sound from PCBs?

Mind you I don't want to disable or remove the RCA jacks because they'll be useful when putting a MAMEpc in there.

Change the speaker wiring on your harness to RCA jacks.

Hmm.. not a bad idea. thanks for that Xian Xi!

I'm somewhat confused here. Are the RCA jacks on the wiring directly to the speakers or are they connected to an amp? CPS-2 outputs line level (pre-amp) from the Q-Sound module so if you connected it directly to the speakers it would be extceptionally quiet (if you could hear it at all). Most boards I've seen with RCA jacks for aux output are like this (line level) and must be run through an amp. JAMMA boards (as well as MVS boards) have an on board audio amp so their output can drive the speakers directly.

If the RCA jacks are connected to the speaker wiring directly, there may have been an amp originally in the cab with RCA outs, or there may have been a board with on board amplification that outputted over RCA jacks. Either way a CPS-2 won't work with that directly if it's as you say.

If you need to make one, the easiest thing to do to get a working stereo amp in a cab is to take the amp out of an old pair of computer speakers, mount it in a project box, and wire the inputs/outputs to whatever connectors you need for the cab. The whole thing can be done for under $10.

If you do have an amp in there already, you will have to bypass it when hooking up a board with an on-board amp, unless you can turn the output way down on the board. Another solution is to just wire an intermediate JAMMA adaptor where you break the audio into a splitter so you can use a switch to either take it from an amped board or the output of an external amp.

Well the cab came with a few CPS2 games and that thing could get L O U D, so I'm pretty sure it has an amp in it. Right now if I put a PCB into it, I get no sound what-so-ever. Here is a picture:



I have no idea what all those connectors are where you see "kick harness?", before you ask me, lol.

But I'm pretty sure that it has an amp in there already. When I put a PC in there it will work great but I wont have money to build said PC for a couple of months so until then I wanted to slap KI in there, I just don't know where to begin. I'm still a n00b when it comes to cab wiring.

Small update. I ended up getting rid of my KI board so it looks like my megalo is going to be a straight MAME cab but it will look original.

My problem is that I'm not getting any sound from the cab's speakers. I tested the speaker outlet on the PC and it definitely IS giving sound, I can hear it on some head phones. I got a standard headphone jack to RCA Red/White cable and some female/female joiners... no sound.

I have no idea why. Any suggestions?

the thing youre pointing to that says kick harness is power for a GD rom. the cable it brances off of and the similar one are jvs power connectors.

just fyi, The item labeled 'kick harness' is not, its a power harness for a GDROM drive. Its connected to half of the JVS power harness, the other part of it is in the pic also (basically anything red/yellow/white on that harness should to be power related.

Also have you checked farther down on the rca jack, near the harness there should be a connector that you can disconnect and connect to another harness of the same type that leads to the audio on the jamma adapter, mine was labeled "line" and something else, I can check later if you need me to.

payment_due said:

Small update. I ended up getting rid of my KI board so it looks like my megalo is going to be a straight MAME cab but it will look original.

My problem is that I'm not getting any sound from the cab's speakers. I tested the speaker outlet on the PC and it definitely IS giving sound, I can hear it on some head phones. I got a standard headphone jack to RCA Red/White cable and some female/female joiners... no sound.

I have no idea why. Any suggestions?

Click to expand...

Depending on your sound card, usually PC audio is line level. You need an amp to hear it on the cab. You could use an amp from a set of PC speakers if you don't have one.

Everyone look away please. I don't want to be shamed.

I figured out my 'problem'. I had forgotten that when I first got the cab, I had removed the marquee which is connected to the speakers. I put it back on one evening and I didn't connect the SPEAKER WIRES that power the speakers!

Christ. Now it's working and I get nice and purty sound. Also, Xian, Im pretty sure the cab has an amp, as it's now working without any external amps.

@Neo Frank, you were right about the other connector. I had another one labled "SPEAKER" but it wasn't connected. After I figured out that I didn't have the speaker wires connected, I didn't even fiddle with that one.

Thanks for the help everyone. Please don't make fun of my tard-ness.

Xian Xi said:

Depending on your sound card, usually PC audio is line level. You need an amp to hear it on the cab. You could use an amp from a set of PC speakers if you don't have one.

Click to expand...

Back in the day, it was 99% speaker level. Passive Externals were all the rage... But Now I am sure that it is almost always line level. I had a few cards with Jumpers to switch between Speaker and Line.

I still always hook my amp up via coax/toslink... Just to be safe (although my receiver can take speaker level audio).

Actually, just about all sound cards had both line out and speaker out.

I'm surprised your receiver has an amplified audio input. I can't think of any reason someone not into superguns would want to connect an already amplified source to an amplifier.