Right now I have a really bad method of capturing audio+video from my cab (pictured here: https://imgur.com/a/l6exCFL ), which basically consists of one of those cheap jamma - -> SCART splitters that just use series resistors (that I bumped in size a bit to be safer). This then feeds into OSSC and then the computer. Audio capture relies on external stereo ports (like in this case the MVS2).
I'd like to replace this with something more proper. One approach would be to wait on something like the Splitfire, which I'm sure would work quite wonderfully!
... but I'd also prefer to just have something hooked up into my cab all the time and not have to worry about big adapters on the jamma cable.
This lead me to the idea of making a small PCB which solves my problem by providing:
- Small footprint! (layout I threw together quickly in kicad is 76x37mm right now).
- Proper audio adaption with galvanic isolation (see: http://hacks.slashdirt.org/hw/supergun/ )
- Buffering and unbiasing of Video and Sync signals to safe levels
- Mini DIN 8 port to easily hook up to OSSC or XRGB Mini
- Audio Jack to hook up audio to computer directly
- Trimpots for video signals
- Cheap! The most expensive parts on the board are the MINI DIN connector and the TY-145P transformer, and both of them together ~10$. Total board parts cost should be less than $20 or so maybe?
Things I'm NOT trying to solve
- No JAMMA connector (big, I don't like Jamma adapters)
- No handling of inputs (this is not a supergun)
- No support for Stereo right now (only really relevant for MVS? and that often has an audio jack anyways...). Handling that edge case would increase the size a lot, by adding another transformer.
I'd love some input on the schematic and board layout before I go ahead and print the first PCB version and order stuff from digikey.
Nothing on here should really be revolutionary or anything. It's about the same circuit as any THS7374 RGB amp, and the exact audio circuit as the supergun linked above (but mono only).
Schematic:
Board:
Known issues:
- Need screw-holes on the board.
- Should have a power led.
- Trim pots should be labeled by their color
I'd like to replace this with something more proper. One approach would be to wait on something like the Splitfire, which I'm sure would work quite wonderfully!
... but I'd also prefer to just have something hooked up into my cab all the time and not have to worry about big adapters on the jamma cable.
This lead me to the idea of making a small PCB which solves my problem by providing:
- Small footprint! (layout I threw together quickly in kicad is 76x37mm right now).
- Proper audio adaption with galvanic isolation (see: http://hacks.slashdirt.org/hw/supergun/ )
- Buffering and unbiasing of Video and Sync signals to safe levels
- Mini DIN 8 port to easily hook up to OSSC or XRGB Mini
- Audio Jack to hook up audio to computer directly
- Trimpots for video signals
- Cheap! The most expensive parts on the board are the MINI DIN connector and the TY-145P transformer, and both of them together ~10$. Total board parts cost should be less than $20 or so maybe?
Things I'm NOT trying to solve
- No JAMMA connector (big, I don't like Jamma adapters)
- No handling of inputs (this is not a supergun)
- No support for Stereo right now (only really relevant for MVS? and that often has an audio jack anyways...). Handling that edge case would increase the size a lot, by adding another transformer.
I'd love some input on the schematic and board layout before I go ahead and print the first PCB version and order stuff from digikey.
Nothing on here should really be revolutionary or anything. It's about the same circuit as any THS7374 RGB amp, and the exact audio circuit as the supergun linked above (but mono only).
Schematic:
Board:
Known issues:
- Need screw-holes on the board.
- Should have a power led.
- Trim pots should be labeled by their color
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Glad it worked out in the first try. Are you able to test it out to make sure it’s outputting proper levels,etc. Also, you thinking of using the better audio transformer?
