Hello,
I received today 3 dongles purchased on Alliexpress. After some not so scientific testing this afternoon, below are my findings:
View attachment 440232
I did the same test on my Windows 11 PC and the results were the same.
What came as a surprise is the CX31993+MAX97220. It has noticeable noise, has the least headroom and the sound seems completely muffle.
It is supposed to be the most powerful of the three so my unit might be defective.
Also, where the two others are quite steady in term of power draw, the CX31993+MAX97220 fluctuates quite a lot when the music becomes busy with a lot of bass. On the Sennheiser, it was fluctuating between 95 and 115 most of the times, but there were also times at 300mW.
For me the clear winner is the CX-Pro with the CX31993 as it has no noticeable noise, seem to have more headroom, and consume the least power by far.
I would also be happy with the CB1200U dongle.
I consider ordering an other CX31993+MAX97220 to see. I might also order a JA11/JM12 with KT02H20 chip and a JM20Pro with CS43131 but those are more expensive, respectively 15€ and 30€.