Audio interference on external speakers when USB-C hubs/docks connected

I have a Framework 13, 12th gen and have been trying to find a USB-C hub/dock to use with it ever since I got it, but have had problems with almost every one I’ve tried.

I have the laptop connected to an external amplifier and speakers via its headphone jack, and all but one of the USB-C hub/docks I’ve tried using cause intolerable digital interference noise on the audio connection.

The latest one I’m trying out is a Ugreen Revodok Pro 210. I have it connected to two 1440p monitors over HDMI, gigabit ethernet, a Logitech wireless keyboard/mouse receiver, and a USB-C power supply, providing Power Delivery to the laptop. As soon as I connect the dock to the laptop, I get a continuous digital interference sound through the external speakers, interspersed with crackles and bursts of static-like noise. I’m struggling to isolate the cause of it.

  • If I move my mouse around, the interference varies in time with the movement, but disconnecting the wireless keyboard/mouse receiver from the dock doesn’t eliminate the interference. It does reduce it slightly though.

  • If I disconnect the two HDMI cables from the dock, the interference reduces slightly, but not completely.

  • If I connect the speaker system to a different device, no interference is picked up, so it definitely appears to be coming through the Framework’s headphone port.

  • Connecting the dock to top-left or top-right expansion slots makes no difference.

  • If I disconnect the USB-C power supply from the dock and connect it directly to the laptop instead, the dock and connected devices still function fine but the interference stops completely.

Other USB-C docks/hubs I’ve tried include:

  • Anker PowerExpand USB-C to Dual HDMI adapter: intolerable audio interference
  • Cable Matters USB-C Multiport adapter: intolerable audio intererence,
  • Cable Matters USB-C to Dual HDMI adapter: very quiet interference, only barely audible when no audio playing, acceptable, been using this one daily

Has anyone experienced a similar problem and reached any conclusions on the cause?