The “Triple Bypass” (3BP for short) is a board that bypasses the audio and video circuits of a Sega Genesis, as well as the DIN (on a model 1). It was originally designed by db Electronics, but has become a true open source project with many amazing contributors. There’s also versions for the SMS, Nomad and others being made by members of the community.
This should be considered an expert-only mod and will (in most cases) disable composite video output.
The Triple Bypass incorporates a THS7374 video amplifier for the RGB video bypass, pushing the Genesis one step closer to clean video output. Depending on your model, you may need to lift the RGBs pins from the board, or add extra filtering capacitors to the board.
Note on model 1 Genesis consoles:
For most people, simply lifting the subcarrier pin will be a good enough video improvement and the audio is already great. I still think installing a 3BP is an awesome addition to a model 1, but check out more information and decide if it’s right for you: https://www.retrorgb.com/genesis1rgbbypass.html
One of the most exciting features of this board is it’s integrated Mega Amp 2.0, originally designed by Ace, but then tweaked by MD Fourier software to get levels that match the best version of the model 1. This means anyone installing the Triple Bypass in a have audio output that’s equal to, or better than original!
The biggest difference can be heard in Genesis model 2 & 3’s though! Genesis 3’s will now have excellent quality stereo audio and the model 2’s all sound excellent, regardless of motherboard version. In my opinion, the difference is extremely noticeable. Listen to the following files with headphones for a good example:
Triple bypass boards will be available to purchase from a few resellers. Links to whoever will carry stock (not just 1-off builds) will be added here:
Current v2: https://github.com/tianfeng33/triple-bypass-Version-2
René’s original v1 with BOM: https://github.com/db-electronics/triple-bypass-kicad
A wiki with full installation instructions is coming soon. For now, please reference the Mega Amp thread for the audio installation on all models not shown below: http://www.sega-16.com/forum/showthread.php?31989-Take-your-Genesis-audio-to-the-next-level-The-Mega-Amp-2-0-is-here!
For the video bypass, you can follow the same basic guide as the original Genesis RGB bypass, which usually involves lifting the RGBs pins from the main chip and pulling raw signals right from the source. For all versions of the Genesis 2 except the VA4, a bottom-install is recommended.
Genesis 2 Bottom Installation: http://retrorgb.com/assets/triplebypass/Genesis2_3BPv2_BottomInstall.zip
Genesis 2, VA4 – The VA4 is the only model 2 we found that’s cleaner with a top-install.
Genesis 3 Installations (scroll down): https://www.retrorgb.com/genesis3.html
Composite Video / HD Retrovision Compatibility:
The Triple Bypass outputs sync on the composite video (cvbs) pin of the multi-out, but not actual composite video. That means unless you use some alternate installation methods (and risk adding interference back into the signal), you can’t use composite video cables, but you can use anything that syncs on composite video.
That means sync-on-composite RGB cables will work fine, including the HD Retrovision cables! Also, the “composite video” pin will always output 75 ohm cync, meaning as long as you use properly built cables, you never have to worry about sync voltages!
This page will be updated with more info and more installation pictures / guides as soon as possible!