Discover the Khozmo 'Shunt Relay' Passive preamplifier. The purest of audio.
In 2014, I added a Khozmo volume attenuator to my Croft preamplifier and found it to be one of the most worthwhile upgrades I'd ever done. Fast forward to 2022 and things have certainly developed. Khozmo has developed one of the best passive preamplifiers I've heard.
Khozmo is based in Poland and is owned by Arek Kallas. Back in 2014, his stepped attenuator was a huge step forward in performance and design. It incorporated solid aluminium casework and could be ordered in series or shunt configurations with a much more flexible 48 steps as opposed to a general 24 steps from other manufacturers.
When I had my Khozmo installed inside my Croft preamplifier, the sound instantly changed. The previous potentiometers I used were by TKD and ALPS, and although they were more of a traditional design, they weren't attenuators.
I did use a DACT attenuator for a short while but I simply couldn't get on with the low amount of steps and I found it to be a little scratchy at times.
The Khozmo stepped attenuator was different. In my case, I tried both serial and Shunt versions of the attenuators with the Shunt becoming my preferred choice.
And using the Charcroft ZFoil shunt resistors made things even more special. But both types performed perfectly and sounded amazing. For more full review of the Croft preamplifier with the Khozmo stepped attenuator fitted, click HERE
Well, in 2022, it's clear to see that Khozmo has flourished and advanced in design and quality. Although Khozmo still offers rotary type units for DIY builds, they also build passive preamplifiers as full units.
This latest design of their passive preamplifier is not a mechanical rotary type attenuated switch but an electrically operated relay system.
Unboxing the Khozmo preamplifier
The packaging of the preamplifier is fantastic. Well thought out to avoid damage. Lifting it out from the box, the first thing to notice was the weight and the solidity of the unit. Weighing in at 2.8kgs with a footprint of H:60cm x W:240cm x D:210cm its compact size is perfect for any audiophile rack or even an AV rack.
The other thing which was instantly noticeable was the quality of the build. It's solid and looks really special.
The look of the passive is very elegant indeed with no unsightly facing fixings. Both the front facia and top plate is made from machined 10mm brushed anodised aluminium and finished beautifully. The rotary controls are also aluminium with a knurled grip and are beautifully inset with a very precise fit.
With 64 steps, the action/feel of the controls is also very solid and smooth. The selector feels solid at each selection point too. It's nice to have a good, confident click!
The volume control rotates very smoothly and because the preamplifier uses electronic relays, it has no start/stop points. So, in other words, the relays control the degree of rotation rather than a typical mechanical control dictating it.
At the centre of the facia is the volume read-out. This is made up of two minimalist inset 3x5 LED dot matrix displays. And at each side are two inset I.R sensors.
At each side of the unit are two 21mm solid wood side cheeks with one side etched with the Khozmo ident. The wood is very smooth, nicely finished and gives it a retro-modern feel.
Turning to the back, the connection panel is also made from the same aluminium. Beautifully machined and laid out to populate the connections. The Khozmo is available in a choice of input/output connections.
The configuration I went for was:
- x1 RCA input
- x2 XLR inputs
- x1 RCA output
- 1x XLR output
As you can see. All of the connections are very high quality. With gold plated Neutrik XLR connections and beautiful red copper RCA connections. The specification can also be bespoke to order. This preamp is in the shunt configuration using Charcroft ZFoil and Takman resistors.
To the bottom right of the connection panel is a mini XLR connector with a threaded fixing ring. This is the power connector that supplies the relays, displays and I.R only. The volume knob isn't motorised because, as mentioned before, the relays dictate the volume and not the control.
Inside the Khozmo
Inside the Khozmo is very well laid out and professionally built. The selector can be seen here and is of very high quality. The relays are by OMRON, which is an excellent choice. As you can see below, the Takman resistors are flanked at each side of the relays and the Charcroft ZFoils are placed on the back circuit board, closest they can be to the input/outputs.
Now let's look at the remote. The remote control for the Khozmo passive preamplifier is really nice. It's made from solid aluminium and has a lovely weight to it. Its design is perfectly simple and has a very comfortable/tactile feel to it. No cheap plastic here...
Even the markings are etched on a brushed top plate. The control has small clear rubber feet which prevent it from slipping around. The reach of the I.R is really good too, you can point it well away from the unit and it still operates perfectly.
Battery replacement is also made easy by simply removing two screws on the underside of the control. So, again, excellent quality and a well thought out design.
Operating the Khozmo
On the unit itself, the selector control has a sturdy, confident click which is nice. It feels solid. The volume control is very smooth. The step sound of the relays inside is nice, not too loud, just right and the dot-matrix display rolls through nicely too.
The brightness of the dot-matrix display can be altered accordingly via the remote. But none of the settings are too bright which is great.
Using the remote, The controls are also nice and simple with just Volume +/-, Mute, Display and Stand-by. In all, very slick, tactile and very simple to use.
How does it sound?
On analogue inputs, I'll be using my Croft as a phono stage and my Studer A80 sending directly into the Khozmo. On the digital side, my Allo Revolution DAC.
Starting with vinyl first. The Croft is an amazing phono stage and has been upgraded by Glenn Croft to an amazing level. So once everything had warmed up, it was time to drop the needle with the Khozmo passive preamp in the driving seat.
The first needle drop was one of my reference albums, Shpongle's Ineffable Mysteries of Shpongle land. The very first thing I noticed was the air in the presentation, a solid, wide image, no confusing elements and the amount of detail is unreal. As the album progressed, more and more detail was pronounced which was previously slightly glazed over with other passive preamplifiers.
My next choice was Pink Floyd - Dark Side of the Moon on vinyl. This is the 2018 Bernie Grundman remaster. This fine album is one of the best remasters I've heard. And being a recording from 1973, it really can punch above its weight.
Again, the soundscape is flung wide open. Listening to this album always makes you understand how much work went into creating it and it's always nice to hear the rawness of the technology from the time. And this is where the Khozmo really allows you to hear the technological make-up beneath the recording.
The Sound with a Digital Source
Connecting up my Allo Revolution DAC, this was my main test... And things were about to bring digital to a new level of excellence. With digital, it can be difficult to hit that none fatiguing sweet spot. But with the ALLO Revolution, this isn't a problem. With a valve-based preamp like my Croft it works perfectly and you would be hard-pressed to know the difference between a digital source and an analogue source.
But with some passive preamps, this can be hit and miss. They can tend to be focused more on resolution over the movement, soul and clout of the music. The Khozmo on the other hand is very different.
Feeding through some Trance/Dub/Dance/Funk, namely Halloucigen, The Prodigy, Shpongle, Aphex Twin, Chemical Brothers, Cavern of Anti-Matter and Yussef Kamaal into the Khozmo, the sound envelops and really allows the bass to organically bloom whilst the mids and highs come through in a very natural and balanced way.
I love it when you can almost see the effects in music positioned in the sound stage. When you hear certain effects and dynamics which bring you back into the listening zone, you know something exciting is going on. I have to say, with the Khozmo in place, this definitely happens more frequently.
Moving on to some rock and classic rock. My next choice was Queen and Led Zeppelin on DSD. If you have grown up listening to these bands then you will know the music and their intricacies very well. The DSD versions of these are excellent and the Allo Revolution DAC handles them with ease. Because we are talking about older production qualities, we have to be sympathetic and understand this.
We have less sub-bass than dance or trance productions but more analogue distortion aimed at the mids and high frequencies. So, how will these classic recordings sound with the Khozmo? Well, the detailed elements, presence and drive which can sometimes be lost with other passives are wonderfully clear as they should be.
Does it make me want to jump up and shake my booty? Well, yes... damn right it does. Moving on to some a-typical 44.1khz Redbook streams the resolution doesn't stop there. Although you can clearly hear a drop in spatial artefacts in comparison to DSD, it's still amazingly good.
For a full review of the Allo Revolution DAC, click HERE
The Khozmo with the Studer A80 Tape Machine
With a duplicated Master tape, the difference between tape and vinyl and digital is like chalk and cheese. You couldn't find a better source for music playback. With a fully calibrated, well-maintained tape machine like the Studer A80, you simply can't get any better for playback or recording.
Of course, tape costs much more than vinyl and to buy a 1st generation duplication of a master tape, the prices can be astronomical in comparison.
So... the only way to listen to a master tape is to listen to it on a Studer A80/A800/A820. In my experience, they're the only machines I would trust. I have a selection of 1st generation master tapes and many recordings of my own. So with the A80 connected to the Khozmo, my first tape was Cream - Wheels of Fire.
And again, this is where the Khozmo came into its own. The sound is precise and superbly balanced. The amount of air and solidity came through superbly, with so much texture and feel. The bass 'flooom' and the kick/snap of Ginger's drums are simply unreal.
For a full review of the Studer A80, click HERE
To have the Khozmo passive preamp in place for vinyl, digital and tape is one of the best additions to the Tannoyista system I've made in a long time. To find such a versatile, bespoke and beautifully made preamp that has all the qualities needed to bring out the best of any source is something very special.
The Khozmo allows the sound to simply pass through like liquid. The sound stage and the presentation of the music space are most certainly very wide and deep with a naturally clearer resolution and no harsh, edgy or fatiguing annoyances.
My previous experience with Passive preamps have always added up to the stage and drive sounding somewhat depleted and whilst the resolution is generally very good, it's not only when you mash both depth and resolution together that you get the full picture of what a true passive should sound like.
Conclusion
The Khozmo relay passive preamplifier has to be one of the best looking and sounding passives on the market. With an excellent build quality and the ability to order bespoke configurations, it's a very special piece of kit.
A good passive should pass the signal through as pure as possible with zero noise floor. But this isn't always the case. The Khozmo, on the other hand, has a purity to it that gently sits you down to listen.
The construction is top-notch and its ability to pass the source through in its entirety is quite astonishing. Resolution, clout and, most important of all, soul, are the key elements that make a great passive, and the Khozmo relay passive preamplifier has it all.
Pricing and details
ul. Strumykowa 6B/58
03-138 Warsaw
POLAND
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