Hello.
Long time ago me and Yogi wanted to do Yamaha OPL3 cartridge from tOri scheme. We never did PCBs. And I have 10x OPL3 + Yamaha DACs at home. Also there will be Lotharek Melody FM cart which I highly recommend to buy as it will be tested. Anyways just for Atari scene backup here are files and Yogi reply to me (last one probably He passed or something happend so He is offline).
"Hi Mat, here is the 2.2 brd file for the cart, let me know if you need the Gerber/Drill files. It's T0ri's board with solder mask stops for the cart edge fingers and some silk screen labels.
Here is message:
Be aware: T0ri designed the board to be etched at home, so he didn't include solder mask or silk screen info. And his schematic is out of sync with the board, meaning that he has added components to the board which are not on the schema.

He also didn't use 'proper' device footprints for a couple devices; L1 and D1. He 'painted' the SMD pads where the parts should go. This isn't too much of a problem unless you plan on using a pick and place machine for assembly.

I've tried to match the board device footprints with the schematic components and label them on the silk screen but there are a couple extra parts on the board. They appear to be extra 0.1uF filter caps on the Vcc.

I also changed the Stereo socket to a different part that matches a Mouser part. Because of the limits of Eagle Lite, had to 'build' the footprint on the board and didn't use a 'proper' part from the library. Again this could be a problem with automated assembly.

I assume from T0ri's page that he has tested the design so the board should be good to go. The biggest issues would be if you plan to have the boards assembled by a third party. They would need placement coordinates for a few parts.

Yogi"
Here are files:
https://www.dropbox.com/sh/om1wy6wjmknx … a1fua?dl=0
Hope Dropbox link will work tell me if not will upload them on my own domain cloud. Also remove *txt to have just gerber files for CAD.

I know author of AdlibTracker2 He is from same country as I also have OPL on my MSX2. FM songs sounds fantastic like on arcade maschine and they are small files sounds like from 90s/80s synthesizer keyboard. Something like ACEtracker on Falcon DSP. Very small files so good for demos, games. I hope one day will buy Melody FM from Lotharek or if anyone will make PCBs and assembly them will send my 10x opl3 and yamaha DACs for free also free original 10 cartridge shells for 2x working FM soundcards...