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Noise and Hum from Headphone Jack

Posted: Thu Feb 17, 2022 6:02 pm
by ferropop
Hi there, been using MiSTer's MiniMig as part of my studio set up! MiSter connected to my audio interface using the headphone jack.

The signal is extremely noisy...and it's 100% related to the onboard fan because when I touch the fan lightly to change speed/stop, the tone of the hum fluctuates with the fan speed.

Any recommendations on how to mitigate this? The noise floor is too high to use this in a serious music studio set up as I was intending to use it :(

Re: Noise and Hum from Headphone Jack

Posted: Thu Feb 17, 2022 6:13 pm
by edr
I've seen noise from the onboard 3.5mm analog audio before.

Not sure how to mitigate, but can eliminate, depending on your setup:
  • If you're doing HDMI to a display and the display provides audio out (optical or analog), use that instead. The display essentially acts as an audio splitter, splitting the audio out of the HDMI. For ex. my TV has optical audio out, and my small LaserBear 10" LCD has analog audio out. My LaserBear provides clean analog audio as long as the display is ON, otherwise it provides static noise :).
  • Whether you're doing analog or HDMI video out, you can take the HDMI connection into a powered HDMI audio splitter, which will give you analog and/or optical audio out. Check Monoprice or other places for some ideas, though I can't rec any particular ones
  • Use MiSTer's onboard mini toslink or full toslink if present, to a receiver/amp with optical in, or speakers w/ onboard optical dac, or powered optical -> analog audio converter (they exist)

Re: Noise and Hum from Headphone Jack

Posted: Thu Feb 17, 2022 8:22 pm
by aberu
If you are wanting to use it for a serious music setup then use an HDMI audio extractor anyways.

https://www.retrorgb.com/hdmi-2-0b-1x2- ... actor.html

96kHz 16-bit is supported by the MiSTer, and it can be output that way over HDMI.

https://github.com/MiSTer-devel/Main_Mi ... Ter.ini#L7

Just have to turn that option on.

Re: Noise and Hum from Headphone Jack

Posted: Thu Feb 17, 2022 11:10 pm
by Wave
Yeah that analog audio out is known to be noisy. Getting digital out in some way is the way to go.