Capturing JAMMA video and audio from New Astro City

[peg]

Posted this over on shmups but figured I'd put it here too.

Any advice for capturing audio off a JAMMA board running in my cab? It looks like a need a line-out converter to convert the audio level to a pre-amp level (I have one of these: https://www.amazon.com/PAC-SNI-35-Varia ... B001EAWS3W) is needed? This one seems pretty straight forward to hook up. Just attach speaker+ and speaker- (it says ground is optional?) and plug in some RCA cables. I'm capturing using a Framemeister and El Gato.

I also read another thread that recommended one of these: https://www.amazon.com/ART-ZDirect-Prof ... ics&sr=8-1). This one seems a lot more cumbersome to hook up and I'm not exactly sure how to do it. Looks like it's used for hooking up instruments to a mixer or something.

Anyway, I just wanted to see if anyone had some experience with this, I'd rather not hook anything up and blow up $1000 PCBs.

Thanks!

[nem]

Audio is easy, just wire up SPK+ and GND to a passive high to low converter. If you wanted, you could make this yourself on some breadboard. Just copy Tim Worthington's schematic from here:

https://etim.net.au/av-driver/arcade/

How are you handling video? You need to attenuate that as well before putting it through the Framemeister.

[peg]

My line out converter has 3 inputs, speaker+, speaker-, and ground. Do these correspond to the same pins of the JAMMA standard?

Do I need to wire up all 3 of these from the JAMMA harness to the converter, or just speaker+ and ground? Do I need to wire up Speaker- at all?

Which one of these would be correct? I just want to make 100% sure I'm doing this right as I'm going to be using some rather expensive PCBs to capture off of.

1)
Jamma SPK+ into Converter SPK+
Jamma SPK- into Converter SPK-
Jamma GND into Converter GND

2)
Jamma SPK+ into Converter SPK+
Jamma GND into Converter GND
SPK- not used on either end

For Video, I'm just using this: https://www.ebay.com/itm/Retroelectroni ... Sw3s9cVgCY

It routes the signal to the Framemeister and also passes it through to the cabinet. There is a slight decrease in brightness when the SCART cable is plugged in but it's barely noticeable and can probably be adjusted for with the POTS onboard (I didn't try).

[nem]

Oh I see. In that case wire up jamma SPK+ to converter SPK+, and jamma SPK- to converter SPK-. You can actually leave out ground altogether.