Review - Myer Audio CKLVX D41

Review - Hidizs S9 Pro

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Also available on YouTube in Spanish: Acho Reviews YouTube 

Let me start out by saying that I am not someone who has tested a lot of dongle style audio devices. I have a few Apple Dongle DACs, and have tried a few of the Creative Labs and similar solutions for laptops quite some time ago, but that is about it. But let’s face it, dongles are in fashion at the moment, with releases from all kinds of companies and at all kinds of prices, from the Apple option at less than 10€ (or even cheaper from some other random brands), all the way up to over 300€ or maybe even more.

I am actually a happy user of the Apple Dongle, it has proven to be of very good quality for its price (which is why I have ended up with multiple units) but there are a few situations in which the tiny device just can’t cut it. This is mainly with over ear headphones, which I rarely use away from my desktop devices anyway, but there are also some IEMs that benefit from having a little more power, especially if we consider the fact that the EU version of the Apple Dongle is only half as powerful as the US version.

So, my review of the Hidizs S9 Pro is really only going to be my opinions on this little portable device in my intended use scenario, without much comparison to anything similar. If you want detailed specs on the S9 Pro, with a full set of measurements etc, along with a very good review (in my opinion), you can check out the review by CqTek here:

My use case…

My main reason for looking for something like the S9 Pro is to have a very transportable device that I can keep in my bag (ok, man purse) and give me something that has a similar sound signature to the Atom and THX set ups that I (usually) use for detailed listening and comparisons when reviewing.

Without going into sound preferences, basically I just wanted something as clean and detailed as possible, while being as small and compact as possible. I also wanted something that I could plug into my DAP to be able to have the same sound reference without being tied to my phone or tablet, more on that in a moment.

As I said, I don’t have much experience with dongles so I spent some time checking out reviews of all kinds of solutions. I don’t think that there was a single one that had all positive reviews, which is to be expected, and some of the most praised were ones that had some kind of “house sound”. Again, my search was for something that didn’t really have a sound, just pure old gain, in order to evaluate IEMs and not necessarily relax and listen.

The S9 Pro seemed to fit this description along with a few other contenders and was actually the cheapest option out of those that were easily available here.

Anyway, I think that is enough random chat, so on to the actual product.


The presentation of the S9 Pro is nothing spectacular. It arrives in a simple black box with some text on it, inside which we find the dongle in a foam cutout. Underneath the top layer of foam we get the included accessories, consisting of a user manual, a transparent clip, a short USB-C to USB-C cable and a USC-C to USB A adapter.

All the necessary bits are there and it is well packed, but again, it’s not really anything exciting for the price.

Build and aesthetics…

The S9 Pro is smaller than I expected it to be, which is good. After seeing photos online, I expected it to be larger than it actually is, which is still bigger than something like the Apple Dongle but is small enough to store in an IEM case quite easily.

The build of the actual unit is ok. Again, I wouldn’t go crazy and say that it is great, although there is nothing really wrong with it. The aluminium frame is nice but the glass covers on each side, which actually feel like perspex more than something like gorilla glass, do move and creak quite a bit when pressed with any kind of moderate force. Really there is no reason to actually press them with any kind of force, so I guess this is just me being picky, but it doesn’t exactly scream “high quality build”.

The included cable is also ok. It seems to be well made but the length is not quite right for my use case. I find that if I connect it to a device (phone, tablet, etc) and place the S9 Pro behind it, the cable is a little too long and sticks out a bit much at the bottom. The cable also came folded in the box, so it has a built in bend to it at exactly the half way mark. However, if I place my device on a stand, the cable is not quite long enough for the S9 Pro to reach the table, so it hangs from the USB port. Again, this is only relevant to my personal use case, it is impossible for a manufacturer to include a cable that is a perfect length for everyone (this applies to all devices, such as headphones, IEMs, amps, etc.).

The clip serves its function well, allowing you to clip the S9 Pro to your pocket or whatever, but if you are using the included USB cable and attaching this to your phone, it means that your phone can only be within 10cm of wherever you clipped the S9 Pro. This can be solved by using a different USB cable but I have found that not all of my USB cables actually work with the S9 Pro and the included one only works one way around. I haven’t investigated this more, so I don’t exactly know what is special about it but it’s worth noting.

Anyway, there is not much more I can say about the build and aesthetics of the device, I think it can be recapped the same way as the “Presentation”, it’s ok but nothing spectacular.


There is nothing really to explain as far as functionality. You plug the USB cable between the S9 Pro and the device you want to connect it to and that’s it, off you go.

My plan, as I said a moment ago, is to be able to use this with my Android devices but also (mainly) with my DAP which is a Shanling M2X. The reason I like the M2X is because it is my preferred size and  it is not Android, it lets me get away from the online world while still being able to stream to it. However, the bad news is that my M2X is still at “the doctor”. I had issues with the volume wheel and they replaced it with a new one. The second one had the same issue so I sent it back (to China) again and they have sent me a new one again. Unfortunately this has still not arrived and I have been without the M2X since February!

But all is not lost, I do have the little brother of the M2X, the M0, which is actually a great little device that I keep in my bag also. It may not be the easiest DAP to use because of it’s size but it does (almost) everything its bigger brother can do. This includes two way LDAC communication, and by connecting the S9 Pro to it, I have been able to use certain IEMs with bluetooth that don’t really place nicely with my other bluetooth solutions, such as the B2 Dusk. It has also let me check that the S9 Pro will in fact work with the Shanling (non-Android) DAPs.


This is the strong point of the S9 Pro, it is a very powerful device for its size. Ok, 200mW balanced and 100mW unbalanced might not seem like a lot when we are used to talking about desktop (or larger portable, battery powered) devices but it is the difference between being able to enjoy the sound from headphones and certain IEMs on something this small or not, as the case may be with something like the Apple option (which I believe is around 30mW).

I have used the S9 Pro this week to drive the B2 Dusk, the iSine LX, HE400se, HD6XX and a few others, all getting plenty loud enough for my usual listening levels from the SE output, however, I would suggest moving over to the balanced output for things like the HE400se and HD6XX, as I don’t listen very loud and I was near full output and the sound certainly seemed to suffer. Unfortunately I didn’t have a 2.5mm cable available for these headphones so I haven’t been able to test them out of the balanced output.

The negative side to this much power is that it also consumes a lot of power. I haven’t really done any detailed tests of battery life on my Android devices (I can’t afford to let them run out of battery completely), but using it powered from the M0 while the M0 was receiving LDAC from my phone, I only got around 2 hours out of the M0. When using the M0 in the same way but without the S9 Pro, I can easily get more than 4 hours out of it (and more when playing local files with BT off). Obviously this will all depend on what you are running from the S9 Pro and how loud you like it. For this test I was running the B2 Dusk at my usual listening levels from the SE output.


Ok, the difficult part. 

I am not going to do my usual rant about how difficult it is for me to compare clean SS amplifiers, so I will just get on with it.

The sound is very clean, what could easily be described as cold and analytical. In comparison to my JDS Labs Atom (which is currently being fed by a Modi 3+), I would say that the S9 Pro seems to be a little brighter. This could just be me imagining things, but it seems that the treble areas can be a little hotter on the S9 Pro (when listening to the same tracks with the same IEMs at the same volume level, etc.). Would I pick it out in a blind test, I would like to think so, but I probably couldn’t, at least at my normal, low, listening levels.

Other than that, I would say that it accomplishes what I set out to achieve with the purchase of this dongle, it is clean, powerful (for a dongle) and does not seem to impact the sound in any negative way with any of my IEMs. I do feel that my planar magnetic headphones seem to be a little more “alive” when connected to any of my desktop solutions, but that is to be expected, there is really only so much available power we can expect from a tiny bus powered device. The HD6XX also does not sound great out of this dongle, it gets plenty loud enough for me but sounds a little compressed.


I like the S9 Pro, it meets my criteria and does exactly what I wanted it to, but I am not in love with it.

I don’t think that I would choose this as my main listening device, I don’t find myself wanting to use this instead of any of my desktop devices. In fact, I would probably put it in the same group as my THX789, it is not my favourite amplifier but it is a very useful amplifier. I use the THX when I am listening for specific things or comparing specific items, but I don’t find myself sitting down and choosing the THX for a long relaxed listening session, the Hidizs S9 Pro makes me feel the same sort of way. It’s true that it can produce some fatigue on longer sessions.

I am certainly hoping not to go down the dongle rabbit hole but I do think that I will continue to look for something that is portable and more “pleasurable”, although that will probably come in a much bigger (and probably more expensive)  package than the S9 Pro.

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