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
I have not experienced what you see as I have a FW16 and not a FW13 but I do have experience of unwanted noise in audio systems.
So it could be one or more of the follow causes:
Noise introduced due to earth currents.
This can be tested by removing any PSU from the dock and the laptop, so it is all running on battery. So that the only thing powered form the mains in the audio amplifier itself. Then see if the noise is reduced or not.
The audio chip in the laptop configured wrongly and receiving input from unwanted sources. This can be sometimes helped by running “alsamixer -c0” or “alsamixer -c1” and muting or minimising the mixer levels so that it only takes the PCM as the source of the audio output. PCM source is direct from the CPU, i.e. playing a youtube video or playing some music.
A DOCK that is creating the interference and thus probably lying about its UKCA, CE or whatever marking regarding EMC compliance.
The audio out circuit in the FW16 not being well enough shielded from interference. I doubt this, because they have done a pretty good job with low noise on the MIC input, I would be surprised if they made mistakes with the audio out.
The audio cable between the laptop and the audio amplifier being faulty. This is unlikely to cause the problems you are seeing, but it is maybe worth a try to replace it.
Possible work arounds:
Buy a USB to TOSLINK / optical output and use an optical cable to link to your amplifier if it has an optical input. This would remove any possibility of ground noise and limit the dock interference considerably. ← This is a very low cost option
Another option is USB to XLR, but that also depends on your audio amplifier inputs.
What make/model is the audio amplifier?
In the end, the problem was caused by an audio switchbox. When I took that out and connected the amplifier directly to the Framework’s headphone jack, there was no interference.
