BetsuBetsu

BetsuBetsu is an Open Source Audio+Video splitter for streaming/recording video from Arcade games (Jamma).

It plugs in between the game and cabinet, and can then be connected to any upscaler + PC for streaming/recording.

Features

• MiniDIN 8 RGB video out (same pins as XRGB-Mini, HAS,...), for hooking it up to OSSC.
• Mono audio output through audio jack.
• Adjustable RGB video levels through onboard trimpots.
• Audio gain can be fine tuned through onboard trimpot.
• Power LED
• Optional Voltmeter can be attached

More detailed features

• Line level audio conversion with galvanic isolation (TY-250P).
• Buffering and unbiasing of Video and Sync signals to safe levels (THS7374). Inputs and outputs are AC-coupled. Safe to drive 75ohm loads / OSSC.
• Audio completely isolated from video (no common ground) to avoid ground loop noise.

Build instructions

• Order a pcb. Kicad plot files are in the plot/ subdir in the repo.
• Order all parts needed (see BOM)
• Solder it up (suggested order below)
  • Start with THS7374. It's the trickiest footprint to solder.
  • Then do all 0805-sized parts in any order.
  • Solder all five big capacitors. Note that the bottom one is 100uF
  • Solder all trimpots
  • Solder the transformer + output jacks
  • Finally add the Jamma connector (make sure to put it on Jamma In)
• (Optional) Add a voltmeter.

Installation instructions

1. Insert the BetsuBetsu into the cab jamma harness and connect the game.
2. Connect "Audio Out" to the PC line-in with a stereo cable.
3. Connect "Video Out" to a OSSC or XRGB-Mini with a MINI-DIN8 to SCART cable
4. Connect OSSC/XRGB-Mini to a Capture card (I recomment USB3HDCAP)
5. Capture/Stream in OBS.
6. Calibrate strength of video signals with onboard trimpots
7. Audio output can be fine-adjusted with onboard "Audio" trimpot.

Schematic (v1.0):

Board:

BOM:

https://docs.google.com/spreadsheets/d/1Nb6cgpz1vrsEBL83Tl52jcXvUmsp_AzcXZ7w7m8aYmA/edit?usp=sharing

Sample capture:

BetsuBetsu + OSSC + Elgato 60 Pro. Scaled to fit inside 1080p in OBS. Audio is wired from Betsu Betsu to PC Line in directly. https://www.youtube.com/watch?v=HWDo_Xj9CUc

BetsuBetsu + XRGB-Mini + Elgato 60 Pro. Scaled to fit inside 1080p in OBS. Audio is wired from Betsu Betsu to PC Line in directly. https://www.youtube.com/watch?v=Qm8Wi2TviPc

Misc links:

Arcade-projects thread: https://www.arcade-projects.com/forums/index.php?thread/10551-betsu-betsu-open-source-arcade-audio-video-splitter-for-capture-streaming/

Misc pics:

Action shot of prototype board in cab: