Allo Katana Player

Allo Katana Player review

The Katana recipe:

The Katana is Allo’s flagship DAC/Streamer, using the popular Raspberry Pi at its base. The Raspberry Pi is a small single board computer running a mostly Linux-based operating system that gives the Katana DAC a network connection and/or local storage for processing and converting music files for your sound system. 

If you need more info on how this technology works read the first sections of my previous review on the Allo DigiOne Signature, which is the same thing in principle, except that the Katana is a complete solution with a DAC where the DigiOne is just a transport that feeds an external DAC with digital signals. 

Where the Katana differs from most other DACs is that it only accepts direct I2S input from the Raspberry Pi and has no external digital audio input available. It will thus not allow you to connect a CD player or any other external digital audio source to it. As a DAC it uses one of the latest ESS Sabre 9038 chips and consists of three PC boards stacked on top of each other. 

The top board is called the Micro Controller. This board receives power that is then regulated and filtered to supply the two boards below with power. You can use a jumper to provide the Raspberry Pi section with power from the same input. The Micro Controller board has circuitry to manage the DAC chip and the DSP filters it applies. It houses a couple of capacitors and a super capacitor. It also provides a way to supply the OPAMP board with separate +15V and -15V power, or just bridge jumpers so that the Micro Controller sorts that out for you. 

The second board is the OPAMP board. This board houses discreet opamp circuitry provided by Sparco Labs. The circuitry amplifies the signal coming from the DAC chip to the levels needed by external gear. It provides the high-quality RCA output connectors that feed your external amplifier or preamplifier directly, and solder points on the board for balanced XLR connectors (if you’re handy enough to solder your own balanced outputs). The board also has an option to feed it separate power (more about this later).

Finally, the third board is called the Katana, which houses the ESS 9038KM DAC chip. It is electrically isolated from the Raspberry Pi below (unless the user decides to bridge a jumper so that the Pi receives its power from above), but receives the I2S digital audio signal directly from the Raspberry Pi. This signal is then reclocked by high quality NDK oscillators before it is sent to the DAC chip. These oscillators have a metal shield over them to block interference and the ESS chip has a small heat sink to help with heat management and I assume also some interference blocking since it is soldered to the board as well and seems like it is connected to ground.

All the above is neatly stacked and secured with copper standoffs and screws on top of the Raspberry Pi. The stack is then housed in a neat laser cut transparent acrylic housing with lots of air vents (this little beast gets seriously hot!). None of the Allo products I have tested before generate near as much heat. The device heats up my linear power supply significantly more than the others. 

At the time of writing, Allo is planning a new aluminium housing that will improve the looks and thermal management of the Katana Player.

Feeding the Katana power – it is thirsty!

In total there are four power connections available and many combinations you can choose to use. 

5V on the Micro Controller board that can be used for the entire stack and Raspberry Pi, or just individual parts of the Katana stack, all dependant on jumper configuration by the user.

+15v and -15V on the Micro Controller board to feed the OPAMP board.

Another 5V on the Katana board to feed only the Katana, or even more boards depending on the jumpers.

And lastly another 5V on the Raspberry Pi. It is not recommended to use this power for the rest of the boards and is only intended to feed the Pi exclusively. It may not provide enough current to the rest and could even damage the Pi if incorrectly connected.

This all is really confusing at first. Luckily my unit shipped fully assembled and configured to run off the top single 5V power supply input on the Micro Controller. So, it is easy to just get it started and working and leave the tinkering and multiple power input configurations for later. 

The moment you start to use multiple power inputs simultaneously, there is a very specific power up sequence that should be followed. If this is ignored the sound that the Katana Player produces is for sure very weird and entertaining at first and then it gets “old” very quickly. The timing is out and may play faster or slower than it should, and sometimes sounds like something from a horror movie. 

It is for this reason that I eventually settled for a single good quality linear power supply feeding the Micro Controller board, as I could not hear improvements with any other combination using the LPS. YouTuber Hans Beekhuyzen came to the same conclusion in his review. There certainly are benefits in using multiple power sources when you do not have one high quality power supply that can deliver enough current on its own.

The Allo Katana User Manual is very useful and clear about the power options available and the correct power-up sequence to follow, as well as their recommended setups. Strangely the single power source option is not recommended. I guess everyone can try and test and decide for themselves what sounds and works best for them. For me it was one good LPS that sounded good and provided the most practical solution since I like to power down and unplug all my gear when not in use for more than a day.

Unboxing and presentation:

Receiving and unboxing the Katana was a very pleasant experience. The Katana is the first Allo Player that I received fully assembled and ready to use. It was meticulously packed with little pieces of foam cut to perfection to fill all the little gaps around the components to reduce pressure points and make the box resistant to compression and bumps from shipping.

The box contained the main Katana unit itself, an Allo 5V power supply and short adaptor to convert the power supply power jack to a USB Type-C connector. The Katana is preconfigured to work with two power supplies (one for the Micro Controller and one for the Pi itself) and they have included an extra jumper to change the power options yourself.

A little welcome/info note was also added to the Katana’s individual packaging for info on the power setup and a bit of a final touch.

One thing I found odd was that the power connector with non-terminated wires to power the Katana separately, was already connected and dangled out the side with wires tied into a loop. To remove this power cable you have to almost completely disassemble the Katana. I guess the reverse is true that if the user wants to use this power option, it would be less effort to install this little cable and connector. But to be honest, I don’t know how many users will actually do this and it looks silly if not used. 

I care about how things look. This should have been provided separately, in my opinion, because the user who uses this option will have to be able to terminate it properly to a connector of choice and will have the technical abilities to disassemble the unit confidently to connect the power wire. I removed it as soon as I realised I could. It was an eye sore. A better solution would have been to place another USB connector somewhere that the user can connect to from outside the case. For the Katana there are now four types of connectors to deal with, one for each power option, and I find it a bit clumsy. The converse is true – you will never get the power sources mixed up when unplugging them and reconnecting them later with each having its own connector type. 

Allo made changes to the enclosure between the original and second released version of the Katana. Most of my pictures shows the original Katana and enclosure. More pictures are planned to follow after this review. These pictures below show the hardware differences between the original and the released Katana.

To be blunt, I am not a fan of the updated enclosure. The openings on the top cover, that give access to the jumpers and switches, are now oversized to also accommodate heat dissipation and are cut in odd isometric shapes. Far too much is exposed. It’s really not a lot of effort for the user to remove the top cover by removing the 4 thumb screws if changes are needed to the jumpers or switches. I think there is a big risk with the current enclosure to damage the electronics with static discharge from your hands and even from physical damage to pins, not to mention that the heatsinks gets very hot to the touch. The top cover could have just been given a bit more clearance from the electronics with neat laser cut breathing holes for heat to escape.

Someone who likes their gear to appear neat and clean might not be entirely satisfied with the looks. It seems that the Katana is built with functionality in mind first of all, with looks a distant priority. For me, a flagship unit should sound great and look great as well.

The Katana was supplied assembled with a clear acrylic housing. When powered on there are a couple of indicator lights that draw your attention to the details. But give it some time and it shows dust accumulation really well and the lights become disturbingly bright. I would recommend and prefer the darker smoky version of the enclosure to hide the bright lights and dust a bit. I am quite keen to see how the aluminium enclosure for the Katana turns out.

Setting up and playing some music:

This was a breeze. The unit came with an 8GB micro SD card that was preloaded with Volumio. It was nearly plug and play.

Please see my review  of the DigiOne Signature where I explain a bit more about the software and setup procedures.

I installed the SqueezeLite plugin on Volumio by selecting it from the setup menus. This way it becomes a Squeezebox emulator and I can sync it up to my other Squeeze players to play the exact same output in synchronized performance to all of them at once. This simplifies A/B testing tremendously. All that is needed is to press the input switch button if you use the same amplifier or preamplifier.

I then fed the Katana RCA output to my Audio-gd NFB1 amplifier on one set of inputs, and the other comparison input set on the same amplifier using the exact same RCA cables. I used a combination of headphones to compare the 2 different sources. I mostly used Audeze LCD2F, Sennheizer HD6XX and Beyerdynamic DT1770.

The other Squeeze players were the original Allo DigiOne serving a COAX signal to my trusty old Breeze Audio ESS9018 Pro DAC and a new Audio-gd R1 R2R DAC, and I alternated that with the original Allo Boss to get a good feel how the Katana performs against the Boss as an all-in-one device.

Over time I have assembled a playlist of songs that I know well and that I may not particularly like, but that have in the past during testing revealed some aspects of music and DAC performance that separated DACs for me. I used these over and over again with this testing. I have found it very difficult in recent times to distinguish between “good” and “bad” DACs. All the DACs in this test are brilliant performers. The differences are in how real the music seems to be reproduced and how it makes you feel when listening to it over a longer period of time. It is not as if you can hear differences clearly anymore or explicitly point out the differences between them by doing immediate source switching of synchronized sources. I find that when you listen to good DACs you have to sit and listen to complete songs or albums to get an idea how it moves you. This is very subjective and will depend on your tastes and music genres you like.

What did I hear?

In a similar manner to how the DigiOne Signature improved on the original DigiOne, the Katana improved on the Boss. There was a clear improvement on the older product. There was less digital grain in the sound, especially in the vocals and with string instruments.

It was giving more realness to the singer and the instruments. More depth or 3D representation. Sound was not emitting from a seemingly flat surface or a flat line sound stage, but a resonating multidimensional body with depth definition. I sometimes found that the sound stage would shrink a bit in width, but the depth and realness I describe totally makes up for it.

Vocals are smoother and fall effortless on your ear. Not shouty or forced at all. In the past I would not describe the Boss as shouty at all but mellow and warm sounding. The Katana is just that much better sounding to me.

So in summary, yes the Katana is better than the Boss, and the DigiOne Signature is better than the original DigiOne. I would say that using the Breeze DAC and DigiOne Signature vs the Katana, the Katana is slightly more pleasant to listen to. More organic sounding and that effortlessness and smoothness of vocals was more intoxicating than anything else I heard during testing.

The Katana, like the DigiOne Signature, was cleaning up the sound quite nicely, with less splashy cymbals, messy rock guitar and bass bleed. They are clearly next generation siblings.

Then, towards the end of my review period, I got the Audio-gd R1 R2R DAC. This complicated things for me actually. Both DigiOne versions sounded better on the R1; and the USB input also sounded great and all inputs now sounded very similar. Compared to the Katana, the R1 was playing slightly louder and after I did some volume matching of the inputs it was shocking how close the Katana performed to the R1. 

There was some sound flavour differences and most probably due to the difference in DAC technology used. One is a delta sigma DAC and the other used a discreet resistor ladder DAC. But both were pleasant to me in their own way. Many may not agree with me, but having used both types of DAC, I would say there is way too much fuss made about the differences between these two DAC architectures. It’s about the implementation of the entire DAC (electronics and power supplies) that determines the final sound flavour and performance it delivers. Both can sound very bad as well.


The Katana is again a game changer in the Raspberry Pi based DAC/Streamer market. It is also currently one of the most expensive options; but I do think you still get much more for your money. This relatively small unit was so close to the R1 that it made my R1 purchase look silly to me. I had some “buyer’s regret” for a moment, but then realised that the R1 has a lot more going on with a much larger selection of inputs and outputs and was a big, properly built DAC in a quality metal enclosure and a very good power supply that you don’t have to tweak and tamper with to get a good sound. In my setup I need multiple inputs and outputs and the Katana will not be able to replace my R1. 

But still, I am sure you would agree that this in itself is a big victory for Allo as the Katana gets a lot done and produces seriously good sound for less money. If you just want a source and DAC in one little box to feed your amplifier, this is serious value. You will not have alternative inputs and a single RCA output (or a pair of XLRs if you do your own thing and solder connectors to the board). And that is enough for most people.

Sound-wise it is excellent and I would recommend it for a dedicated listening setup that only needs one steady input from a DAC that you stream music to over your network. It is quiet, small and just works when you have finished the initial setup. You only need your phone or tablet in your hand to command playback from the Allo Katana. 

This product is purpose built and in the hands of a purpose driven audiophile, the Katana could definitely be a precision tool.

Well done Allo. I am looking forward to what you come up with next.


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