Just to add to the confusion (from a
review):
"This (the Quedelix) little device is one of my favourite dongles. I think there is little else that comes close in performance and sound for the price. It is clear that the Hidizs S9 Pro does not have many of the features of the 5K (Bluetooth, control APP, control buttons, in-body clamp, battery). However, it does have a higher level of decoding (768kHz/32Bit and DSD512), compared to the 24-bit/96kHz, no DSD playback in USB DAC mode of the 5K. On the other hand, in power they are very similar, with the S9 Pro at 33Ω being more powerful due to the SE output (130mW vs 110mW). However, the Qudelix is more powerful due to its balanced output, reaching 260mW at 33Ω, compared to 230mW at 33Ω for the Hidizs. The 5K has no ASIO drivers and its DAC is the Sabre Dual ES9218P. Both devices have an output impedance of less than 1Ω.
If with the previous device the differences were small, between these two, the sound is once again very similar. Not surprisingly, it is once again Sabre vs Sabre. And the fact that the Qudelix has a Dual DAC allows it to compete with Sabre’s top of the range DAC. After several hours of comparisons, my feelings are subtle in this respect. A priori, I find the Qudelix a little more analytical, where the smallest details and nuances seem to be revealed more easily. However, I get the sense that the S9 Pro sounds more defined and higher resolution, offering a darker background, a little more separation and air. In the low end of the S9 Pro, there is a little more punch and speed, when playing the lower range. Lower notes seem to be reproduced more concisely and tightly on the Hidizs. On the other hand, the 5K’s vocals are a little more present and closer, sounding a little more complete.
As for the scene, slightly cleaner and wider on the S9 Pro, with a bit more air and separation, plus that slightly darker background.
It is a difficult choice between two great dongles. But the preference for one or the other should be based on two aspects: if you want to play music with the highest fidelity and quality, I would choose the Hidizs S9 Pro, because of its ability to play PCM up to 768kHz/32Bit and DSD512 and because its sound is slightly superior. But if you want to use Bluetooth and exploit all the capabilities that the Qudelix offers with its APP, it is clear that the choice will be the 5K. And on this I can’t fool anyone."
About the
S9:
"The only issue I have is a little bit of peakiness in the Upper Mids/Treble, which can become a little distracting with certain pieces of music. It may also become fatiguing over time if you’re sensitive to that kind of thing.
However, the boost in that part of the audioband does provide presence and airiness the competition doesn’t have. So if you like a little extra sparkle on the top end combined with decent technicality overall, you should check out the S9 PRO. It will definitely be an improvement to the built-in DAC on your smartphone."
S9 power consumption: