Calyx K

Today I want to take a closer look at the Calyx K Dac/Amp. I got my unit from the South Korean Calyx-audio company in exchange for an honest review.

Maybe I should begin my review with the information that I was a Calyx M DAP user for many years. I most probably wouldn’t have sold my Calyx M units (I had 4 units in the past, two of them modded, but I always came back to the original one). But there was a time when I decided to go the streaming route (Qobuz High-Res) and as the Calyx M was not able to do that, I had to move on. That being said, I never forgot the special sound of that device. I also had the LPGT Ti for a year or so, but came back to the Calyx M (LPGT Ti did cost nearly 4k Euros back then, the Calyx M did cost 400 Euros when I bought them … so you see that „sound“ doesn’t always correlate with „money“). LPGT Ti sounded somewhat artificial. Calyx M sounded real, alive.

Anyways, when a good audiophile friend of mine posted the news of the portable Calyx K in the dedicated Calyx thread here on head-fi, I was instantly intrigued.

The Calyx K comes in a tiny black box as you can see in the pics below, the only accessory is a short USB-A to USB-C cable. This cable works just fine when connected to the laptop (though I need a further USB-A to USB-C cable in order to plug it into my Macbook), so here I would have liked to see at least a USB-C to USB-C cable also for the usage with a mobile phone. An Apple lightning to USB-C cable would have been great, too of course.

When you take the „K“ into your hand for the first time, you immediately feel its „worth“, in other words: It is quite heavy. But a nice kind of heavy if you know what I mean. No plastic parts. Except the nice thick rubber layer beneath the device that sticks nicely to the desktop surface. Very high build quality overall! 142g. 86mm x 52mm x 18mm. So you see it is not a small Dongle DAC. I had the Questyle M12 and M15 back then and they were small, at least the M12 was. The K is bigger and heavier. But its sound!! … well, let’s just dive into that:


Sound impressions:

From my memory I can tell you that the K at least is on par with the (holy) Calyx M DAP. Everything is there. Nice, deep, clean, articulated bass that is not overdone; transparent mids with no exaggeration of the upper mids, smooth but nicely extended highs. An analogue sound that one wouldn’t expect coming from a „dongle“ DAC. Listening to this device was like coming home again. You wouldn’t want to change anything here soundwise. Just pure music streaming through, everything laid out before you. But mind you, this isn’t a „warm“ sounding DAP at all. In my view it is neutral/natural but without any harshness, maybe that’s why I used the word „analogue“. The stage is wide. I didn’t detect any hiss (though sometimes, when the device is on top of the mobile phone I hear a quiet sound like crackling when there’s no music playing).

It is a plug and play dongle. Nothing to install for android phones either and it works flawlessly with my iPhone 15. There are no volume buttons on the K, no filters, no skip tracks or play/pause buttons … and well, in fact nothing else. A minimalistic device that concentrates on the music quality alone!

There is a rather loud „plop“ sound when connecting the mobile phone to the K. So you maybe want to wait putting on the headphones and firstly connect it to the mobile phone or the laptop.

The small blue light stands for „connected“ as well as PCM audio, and supposedly a red light for DSD audio (didn’t test DSD files). If it was for me, I wouldn’t need a light at all. As you can see: I like a minimalistic approach.

As with the Calyx M, the Calyx K has its caveats: For starters, it isn’t the most powerful device out there. You won’t have any problems at all concerning driving power when listening to IEMs connected to the K, BUT with demanding over the ear headphones there is a limit. I am happy that my AKG headphones work well (but I have to crank up the volume on the iPhone 15 for about 95% of the possible volume). So almost no headroom here. Older albums that were not mastered as loud as today’s recordings are too quiet. So you have to know: Focal headphones with low impedance or the new Austrian Audio Composer will work nicely but the DCA Stealth or Susvara or Senn HD800 etc. won´t be a good match, at least not if you like to listen to louder volumes.

You also have to know that the K just has a 3.5mm out. So no balanced 4.4mm out. It would have been convenient to implement a 4.4mm out even if it wasn’t a „truly balanced“ output, so one doesn’t need to swap the cables all the time which might be a hassle especially with IEMs. But of course there are 4.4mm to 3.5mm adapters from different companies, too. So that would be the best solution if you don’t use a 3.5mm plug.

In addition I would have liked to see the USB-C port and the 3.5mm port on the same side. I don’t have any problems putting the device into my pocket when connected to the mobile phone but it would have been nicer and more convenient if the cables would be on one side only, also for the longevity of the cable´s plug.

I reviewed the Quloos MUB1 recently that costs twice as much. And that device has an additional 4.4mm out as well as volume buttons, skip/track/play/pause buttons, it has different filters, a built in battery, a „desktop mode“ etc. and all those things to play with as well as a very nice bluetooth implementation. It also has many gain settings and enough power for demanding headphones. But - and this is a big BUT - it doesn’t sound as good as the Calyx K!! Not even when used in balanced mode. MUB1 is just too warm in comparison with a bass that bleeds into the mids and so the mids won’t be as transparent and the vocals won’t be as present as with the mids out of the K. Also the highs are not as extended as with the K. So if you listen to IEMs as well as not so power demanding headphones and you don’t need bluetooth but just want the purest (analogue) possible sound from a portable DAC/amp, just grab a unit of the Calyx K, especially for that price! For me sound is always the most important thing, that’s why I did stick to the Calyx M for so long (although it also had some caveats.) I also tested the Astell&Kern SP2000 Copper edition back then parallel to the LPGT Ti. I still did prefer the Calyx M for sound alone. And what applies to the M (soundwise) also applies to the K.

If you plan to listen to the device on the desktop table, the USB cable that came with the Calyx K is completely sufficient. But if you plan to listen on the go with the mobile phone or you need a USB-C out from your laptop, then I highly recommend the (alas rather pricey) ddHifi TC09S cable or the lightning equivalent MFI09S. Because I tested the Calyx K connected to the USB-C to USB-C cable that came with the Quloos MUB1 (they had those cables in the box as it should be!), but I came to the surprising conclusion that the Calyx K sounds even better with the ddHifi cable. There shouldn’t be a difference because it’s a digital cable but maybe there is one because of the separated cable for the power supply? I don’t know. Just buy a ddHifi cable online, test it with your system in comparison with other cables and if you don’t think you hear a difference, just send it back and get you money back. But if you (like me) hear a more expanded soundstage and a somehow more powerful and clearer sound, then it´s a win win situation not only with the Calyx K but with any DAC!

The unit costs USD 300.- // EUR 300.- (edit: new price) including shipping. You can order it via their official Calyx Facebook page (https://www.facebook.com/calyxaudio/) or direct order via ask@calyx.kr and payment through Paypal via order@calyx.kr

One thing is clear: You will hardly find such a small device with such an extraordinary sound for that price.

Thanks for sticking with me, guys! And concluding here are some pics of this beautiful device: