A new ‘REAL REVIEW’ By Alex Colburn, product reviewer @HIFIWIGWAM

It doesn’t happen very often but when Linn launch a new DAC architecture you better sit up and pay attention. September 2016 saw the launch of the new Katalyst DAC architecture in their Klimax range of digital streamers, Linn’s fourth generation DAC and first since their original move into digital streamers back in 2007. Ever since the original launch of the Klimax streamers they have consistently scored very highly in performance both in terms of accuracy and musicality.

The new architecture is built around the Asahi Kasei Microdevices Corporation (AKM) AK4497EQ 32-bit 2ch DAC. Linn engineers selected the AK4497EQ after extensive auditioning tests showed it to be the outstanding performer of the best DACs currently available. AKM have structured the chip in a way that allows the designer to access the various separate stages in the conversion process. Linn engineers have taken full advantage of this by providing independent isolated power supplies tailored to each stage, a noise isolated high-stability reference level, a single high precision low jitter clock and custom digital data optimisation stage. To preserve the ultra-low distortion and noise performance of the AK4497EQ, Linn have also designed a new ultra-low distortion analogue output driver stage. Currently, Katalyst is only available in the top of the range Klimax digital streamers with analogue outputs but there are plans to roll the technology down through the product ranges.

Linn’s “Konfig” software is how the user accesses and sets up the extensive configurable functions in the KDSM. The official designation of the Katalyst Klimax DSM is KDSM Mk3, at least this is how the Konfig software identifies it. Linn have completely re-written their Davaar firmware to accommodate the Katalyst architecture with the release of Davaar 50. The Klimax case is nicely compact at 350mm wide 355mm deep and 61mm high. Available in anodised silver or black, the casing is machined from a solid billet of aluminium and weighs in at a fairly hefty 8.6kg. Internally, separate compartments are machined to electronically and mechanically isolate analogue, digital and power supply components. Power consumption is 22W in active mode and 20W in sleep mode with the case temperature stabilising at 32˚C in my 21˚C listening room.

The KDSM is an integrated digital streamer and analogue pre-amp with additional analogue and digital inputs and outputs. Layout on the rear panel is pretty tight and with the rear case overhang it can be a challenge to make connections to the various sockets when reaching round from the side or the front. The rear panel sports two stereo transformer isolated analogue outputs, unbalanced RCA and balanced XLR each mode selected via the Linn Konfig software. Though signal will appear at both outputs, they should not be used simultaneously as the configuration mode optimises each output according to the desired selection. One stereo balanced XLR input is provided that can be configured for sensitivity with Konfig. A pair of Neutrik RCA to XLR adapters are supplied with the unit so that single-ended sources can be connected to the analogue input.

Katalyst brings a new digital output to the KDSM with the ability to configure the bidirectional SPDIF port as an input or output using Konfig. Any change to the SPDIF port directionality requires a reboot of the unit. Additional digital inputs include two Toslink optical ports. Three HDMI inputs and one HDMI output are provided for those wishing to integrate the KDSM into their AV system. The new upgrade also brings HDMI 2.0 to the KDSM with support for 4k video, HDCP 2.2, HDR, CEC and audio return channel (ARC). The HDMI 2.0 upgrade is also a retro-fit available for earlier versions of KDSM and some other Linn product ranges. Three RJ-45 sockets adorn the rear panel, one 100Base-T Ethernet connection for a local network and two proprietary Linn Exakt Link sockets. Mains power is connected with a slim style IEC plug, exotic plugs such as those from Furutech will not fit due to the close proximity of the casing.

Linn provide a range of software apps that allows you to control your streamer from a desktop, laptop, tablet or phone covering a range of operating systems. Linn’s adoption of open source software development also means there are numerous third party control points available. The remote control that comes with the unit can be used to control most functions but it is a much simpler process to use one of the control apps for anything more than just volume or muting. A local network connection is required for control and to stream music from a local server or directly from the net via a music service such as Tidal or Qobuz. Both Tidal and Qobuz streaming services are built into the Linn Kazoo control software. Audio formats supported include, FLAC, Apple Lossless, WAV, MP3, WMA (except lossless), AIFF, AAC and OGG at up to 24-bit 192kHz. Linn do not support DSD even though the AK4497EQ has hardware support for it but may possibly introduce DSD through some future firmware release if the new architecture will permit it.

Space Optimisation (SO) is a Linn software innovation that uses acoustic modelling techniques to build a complete model of your speakers, their placement and the characteristics of your listening room. The digital signal processor (DSP) at the heart of the Linn streamer uses the model to correct for room interactions in real time. Setting up SO is a relatively simple task implemented in the Konfig software requiring the input of room dimensions, wall and floor construction, speaker position and speaker model and type. Although SO makes all the model calculations automatically, the model can be fine-tuned manually or established by measurement with a calibrated microphone and spectrum analyser software. Considering this is effectively a free software upgrade for Linn streamer owners and it brings a considerable improvement in the performance of your system, using it is therefore a complete no-brainer compared to expensive room treatments.

Listening tests were conducted with SO activated and set up manually using a calibrated test microphone positioned at the optimum listening position and 1/20th octave TrueRTA real time audio spectrum analyser software. Following initial installation, the KDSM Mk3 was powered 24/7 for approximately 200 hours prior to any serious listening. Music was sourced from a local network storage device running MinimServer in FLAC format.

My most immediate impression was that the system was now portraying the music against an exceptionally dark background which was presumably due to the lower noise floor of the Katalyst architecture. The decay of instruments was delightfully extended and precise with the acoustics of the recording location being faithfully reproduced.

Peter Gabriel’s album Half Blood (24bit/48kHz B&W Society of Sound download) is a fine example of his collaboration with John Metcalfe and the New Blood Orchestra. Soundstage presentation is excellent with great depth and width and solid 3D positioning. Separation of instruments is excellent both spatially and temporally, nothing seems to merge and become ill-defined. Jennie Abrahamson’s vocals on Downside Up are presented with a very natural ethereal quality. The kettledrum towards the end of The Rhythm of the Heat has great attack and perception of the drum skin vibrating in real space. Bass instruments have great structure and definition and therefore are much more real for it.

Michael Murray’s Bach: Toccata & Fugue in D Minor (24bit/44.1kHz Telarc CD rip) brings alive the organ of the First Congregational Church in Los Angeles. A very real image of this stunning instrument within the church is rendered accurately with the building acoustics and all the organ notes from the highest down to the lowest of the low.

Agnes Obel’s Aventine (24bit/96kHz Qobuz download) is the closest I’ve come to having a grand piano in the living room and the close miking of her voice puts Agnes right there sat in front of it. The cello on Fuel to Fire is also delivered with good depth and great timbre.

Ed Sheeran’s X (16bit/44.1kHz Asylum CD rip) is his finest work so far IMHO. I’ve always been a fan of Ed’s “Little Martin” and the way he abuses it in his unique musical way and the KDSM doesn’t disappoint on that front. Every fret move, note and body slap is delivered with precision and crystal clear definition.

By complete contrast, William Carter’s Fernando Sor Early Works for Guitar (24bit/192kHz Linn Records download) is a study in baroque guitar work. Though not my cup of tea, I can appreciate it is a very fine recording and really brings the artists performance to life. Similarly, Pamela Thorby’s Garden of Early Delights (24bit/88.2kHz Linn Records download) is a dazzling showcase for Pamela’s baroque recorder mastery.

Van Der Graaf Generator’s Pawn Hearts (16bit/44.1kHz Charisma CD rip) is a fine example of well-recorded prog rock from the 70’s and one of my favourite albums from that era. Not being everyone’s cup of tea, this is not the album to troll around the shows asking to be played. Having played this to death over the forty-odd years since its release it has come to be something of a reference recording for me. Needless to say, the Katalyst KDSM has given me the best rendition I’ve heard to date. Guy Evan’s drum work is fast and dynamic with superb cymbals and Dave Jackson’s sax on “A Plague of Lighthouse Keepers” sounded particularly haunting.

Since starting to write this review I have listened to a much wider range of music and TV/BluRay material through the KDSM’s digital inputs than I have reported here. If you don’t need the preamp with analogue and digital inputs the KDSM provides you may prefer to go for the cheaper KDS that is simply a streamer and only has analogue outputs. Katalyst KDSM is in no way a tone control and can be ruthlessly revealing of any flaws in the recorded material, a particularly sibilant live recording of Jon Anderson’s voice is reproduced in excruciatingly fine detail but if accuracy is what you want that is what you get. As you would expect, performance is at its best playing hi-res material so there is a high probability of being turned into something akin to a hi-res junkie. I have to admit to buying quite a lot since its arrival.

I don’t like to say this for fear of generating controversy but it sounds more analogue than analogue or maybe better put, it sounds like what analogue should sound like IMHO. But then it’s digital not analogue so maybe Katalyst digital is the new analogue, I’ll leave that for you to decide…

Linn’s Katalyst KDSM is the finest digital source I have heard in my system and probably anywhere else. If you are looking for the very best in accuracy and neutrality from a digital source then Katalyst is right up your street.

As Klimax is Linn’s flagship range ownership cost of Katalyst is not cheap, the KDSM Mk3 will set you back £18900 but if you are lucky enough to already own a Mk1 or Mk2 version you can have it upgraded to full Mk3 specification for £4200. If you don’t need the preamp and its inputs then the Katalyst KDS will cost you £15800 or you can upgrade from a previous version for £3950.

Associated review equipment:

Power amplifier: Nord One UP NC500DM ST with SI994 input buffer

Speakers: Modified Townshend Glastonbury Tor Mk1/Townshend Maximum Supertweeters

Interconnects: Nordost Tyr 2 balanced XLR

Speaker cables: Nordost Heimdall bi-wired Z-plugs

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