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Capcom ZN-2 Stereo Breakout board

Thank you everyone for the support. Especially to those who contributed <3 I am very grateful.

The board files are officially available, you can get them in gerber format, or KiCad source files. A BOM is also provided to help you find the right parts. I suggest buying from digikey.

https://github.com/simonlc/zn2stereo

The files are licensed under the TAPR Open Hardware License (www.tapr.org/OHL).
 
I got my pcbs in today so I built a couple. So far so good! I couldn’t find a system setting on Gnet for stereo (just the motherboard switch) but I only tried one game and the menu was Japanese... so I’ll play with it more in the coming days. Worked fine on a Capcom zn1 BAT2.
 
ekorz said:
I got my pcbs in today so I built a couple. So far so good! I couldn’t find a system setting on Gnet for stereo (just the motherboard switch) but I only tried one game and the menu was Japanese... so I’ll play with it more in the coming days. Worked fine on a Capcom zn1 BAT2.
Click to expand...
Great, thanks for testing and the support! <3

I'll update the github for zn-1 as working :)
 
I was going to say zn1 Raizing/8ing has a problem, but then I noticed two caps were missing from my motherboard!
 
I think you might have the circuitry wrong, this is the original from Sanwa, notice it says JAMMA 10 but it does not say JAMMA L.

For the RCA GND it uses the ground symbol i.e. pins 1,2,A and B. This is very similar to how Konami does it.

However in your design you are using RIGHT- and LEFT- as a replacement to GND but what you are doing is shorting the output of the differential amplifier.


sanwa_vc-j_original.jpg
 
Wow, thanks for point that out @rtw :o I always thought speaker- and ground were equivalent. To get ground to the board it would definitely require changing the design a bit more. I'm assuming shorting the amp is bad? I will try to hook it up to ground and see if I get better sound.
 
Simon said:
To get ground to the board it would definitely require changing the design a bit more.
Click to expand...
indeed. I was helping everten wit the circuit on his F3 Stereo board. and I'll point you to the same link I pointed him: https://electronics.stackexchange.com/a/12205

I think the key is that you need to understand the difference between "balanced" and "unbalanced" audio.

essentially:
unbalanced audio uses ground for the negative (usually) audio pin.

balanced audio outputs a wave form on the negative pin that is inverted from the positive pin. (so if the positive pin is 5V then the negative pin would be -5V and if the positive pin is 1V then the negative pin would be -1V, etc.)

The benefit of a balanced output is that since the "ground" reference point fluctuates with the signal it naturally eliminates any hum or noise generated by other components in the same electrical system.

Some JAMMA boards are blanaced, others are unblanaced and simply have the speaker - tied to ground.

I've also seen some weird setups with speaker + tied to ground and speaker - outputting the inverted wave form.

Some Taito hardware, including G-Net and the FX-1 hardware (both ZN boards). Do a really NEAT thing with the audio to get Stereo output on the JAMMA edge. In that the speaker + is the positive wave for one channel, and speaker - is the inverted wave of the OTHER channel. The result is that on a mono cab the two wave forms naturally merge into mono sound. however in Taito cabs designed for this output config (such as the Egret 29, and Egret II) they tap ground from another pin on the JAMMA edge and then feed the speaker - and speaker+ to the appropriate pins on the left and right channel, so you get stereo sound over JAMMA without any special wiring. :D

Despite G-Net and FX-1 hardware doing this, it doesn't seem to be the case on NON-Taito ZN mobos, so they must have some audio wiring differences, at least in regards to the JAMMA edge.
 
Simon said:
To get ground to the board it would definitely require changing the design a bit more.
Click to expand...
Hey @Simon the components I ordered from Digikey have finally started to ship...
So my question to you is, should I complete the build as-is and rework it (trace cuts/jump wires)?
Or wait, saving the components for a new/updated PCB design that you will release at some future point?

Thanks for all the work on this. :thumbup:
 
I still haven't had a chance to test this :) Sorry for the wait. I am on vacation this week, I will try to check it out! If I update the design I'll do the screw post, thanks for the tip!
 
Simon said:
If I update the design I'll do the screw post, thanks for the tip!
Click to expand...
Hope you update the design, as the PCBs are cheap/fast to have made.
If you decide not to however, could you post up some easy modification directions for the current/last revision PCB?.

I'm AOK with trace cuts and jump wires. :thumbsup:
 
Hi! :)

I am looking for the equivalent of the Sullins PPPC041LFBN-RC 4 Position Total Single Row 2.54 mm Pitch Straight Female Header
connector on Mouser Electronics .

Any ideas ?

Thank you :thumbup:
 
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