Sega Astro City - Sound Amp Static Monitor Help

[NeoField]

Hi team,

I've got an Asus ROG Ally running into my Sega Astro City through a downscaler (video looks great), and I added a Lepai LP-2020BT amp (Amazon ASIN B0CWLSQN58, https://www.amazon.com/dp/B0CWLSQN58) to drive the stock speakers (sounds great too).

The problem: whenever the amp is powered on and connected to the PC, I get bad static on the monitor's video. Here's what I've already tried, none of which made any difference:
- Switched the amp to Bluetooth instead of a wired audio connection
- Added an audio ground-loop isolator/de-noiser on the audio line (ASIN B06XQYN77L)
- Put the Astro City power cable and the amp on different wall outlets

Short video of the issue:

View: https://youtube.com/shorts/wXtU9jHOzBY


Any advice would be greatly appreciated! Thank you!

 

[Thomas]

I'm going to guess that the ROG Ally is generating that noise in the video signal when the amplifier is connected to it. Try that same setup on a different monitor and see what happens.
Or try disconnecting the amp from the Ally, keep the Ally and amp powered on, then play audio through the amp using your phone or anything with an audio line out connection. If you still see noise on the screen then there is an interference issue somewhere. Start moving devices and cables and speaker wires around and see if anything on the monitor changes.