Randomly occurring popping noise from USB audio speakers

I have noticed that my excellent small YU2 stereo speakers, which have their own DAC and internal amplifier and which accept USB sound output from my PC, have started to make low cracking or popping noises at random intervals.
YU2 do not supply drivers, just stating that Windows will automatically install the correct drivers, and I suppose that this happened when I first connected the speakers.
As far as I can tell, the driver in question is C:\WINDOWS\system32\drivers\usbaudio.sys version 10.0.26100.2454
I have attached three screen snips from Device Manager. I think that the NVIDIA item drives the sound from the built-in speakers (not used) on the Monitor, and the Realtek item is for SpDif audio output (Not used).
I notice that Windows has also downloaded, but not actually used C:\WINDOWS\system32\drivers\usbaudio2.sys. I don't think that these speakers are USB Audio Class 2 devices, but in any case, I cannot force Windows to accept the usbaudio2.sys driver for my device.
I have tried to update the usbaudio.sys driver, but Windows tells me that it is the best driver available.
I have tried running the Windows audio troubleshooter, but it asks me to reproduce the problem as it tries to diagnose it, and because the noise occurs randomly, I can't do what it wants.
I have not yet tried to connect the speakers to the stereo audio output from my motherboard (Gigabyte X570 Aorus Master) using the speakers' 3.5mm aux input, because I wanted to use the (superior?) DAC and amp of the speakers, and also because I cannot find the interconnect cable for this purpose that came with the speakers. (cables ,cables everywhere, they get in the feet, they get in the hair ....)
I would very much appreciate any help.

I'm a little confused. Are these usb speakers attached directly to your computer or are they conneted to a usb port on your monitor?

They are connceted by a single USB lead to a spare USB socket on the back of the PC.
I have located the lost 3.5mm jack plug lead which plugs into the back of the PC and to the back of one of the speakers, instead of the USB lead. Using it has cured the problem completely, but, of course, in so doing, I am not taking advantage of the superior DAC in the sepakers.