Reply To: OSSC Audio not working on AV1, except with Mega Drive 1

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#22113
nmalinoski
Participant

Hello, I have an OSSC 1.6, and I have a scart lead that integrated a phono in from the Mega Drive’s headphone port. This is plugged into the OSSC’s headphone jack.

Some quick clarification:
– The 3.5mm TRS jack next to the HDMI port on the OSSC isn’t intended to be an input for AV1–it’s a line-level breakout for AV1 or line-level input for AV2, depending on the state of the adjacent toggle switch.
– ‘Phono’, as I understand it, means unamplified audio from a phonograph, and a ‘phono’ input on a receiver or amplifier will apply both amplification and an RIAA curve.
– If one of these jacks is designated ‘headphone’, it is output only, never input; and it includes amplification to power headphones, rather than being line-level.

It will function as an input for AV1 if it is set to AV1 output and the scart audio pins are otherwise not wired up I think I remember seeing, but generally I don’t think (and someone correct me if I am wrong) it was intended for feeding input audio from a gen/md model 1 headphone jack.

If it functions as one, like you say, when audio is not otherwise wired up, then I would call it an unintended side effect and not any kind of functionality that should be relied upon.

Update: I unplugged the phono line in and suddenly sound was restored.

Is there a setting I’m unaware of to enable / didisable how the jacks work? And why would the functionality suddenly change? (Maybe I changed a setting by mistake?).

As ErebusMaligan mentioned above, that jack is not intended as an input for AV1. It sounds like audio was connected in the RGB cable, and that was being bridged with the audio from the MD’s headphone jack. I’m not sure exactly how that would cause no audio, but it apparently does.

If you’re okay with the mono audio from the RGB cable, I would recommend you continue to use just that RGB cable. If you want stereo, and you’re comfortable modifying the cable yourself, you can disconnect audio from the console and wire up a 3.5mm TRS lead that would connect into the headphone jack on the front; otherwise, you can get this kind of cable premade from Retro Gaming Cables (Regular version, PACKAPUNCH version).