"What a refreshingly honest blog about listening to music through hi-fi. So happy to see views based upon the enjoyment of music rather than so-called sound 'quality'." - Peter Comeau, Director of Acoustic Design at Mission / Wharfedale

Sunday 26 May 2019

Inside Linn's Majik Exaktbox-i (pre-Katalyst)

As usual with Linn's Exaktboxes and power amplifiers, I recently lifted the lid on the Majik Exaktbox-i used for Exakt filter designing, to dim down the excessively bright blue LED behind the front panel.  That involves removing the sleeve and then the front panel in order to paint the LED with a Sharpie and then to fit it with a "lightdim" disk.

Whilst I was in there I took some pictures so we can see what the equipment looks like inside:

Plenty of ventilation on the underside

General overview - note that the power supply section (down the centre) is not branded "Dynamik" in the normal way, even though it is a Dynamik power supply

One half of the power amp sections

Speaker terminals

Ribbon cable attachments

The Exakt processing board sits over the top of one half of the power amp boards

Exakt Processors

Ribbon cables and dual cooling fans

Channels 5 to 8 power amp board id

Exakt processing board id

Good view of one of the centralised heatsinks

Exakt processor board close up

Dual cooling fans and central status LED - this is the one I've painted with a Sharpie and then covered with a lightdim

From the front of the left hand side power amp only board

From the front of the right hand power amp board (channels 1 to 4) and the Exakt board above

Saturday 11 May 2019

4 Lots of Kudos in One Night - Passive and Active

Kudos' Titan 808 has been around a few years now, and has given a great account of itsself at multiple shows 'musings has attended in the UK and Germany.
Most recently with the rather good Naim SNAXO active system at the Chester Hifi show earlier in the month.  I also chose a Linn Exakt driven pair when presenting a "MyTunes" playlist evening at Manchester dealer brianandtrevors, where they were augmented by a pair of REL No 25 subwoofers.

But there's more to Kudos than their well received top of the range T-808.  There are entry level "X" models, mid-range "Super" models and 4 different interpretations of the Titan formula.  So what's the rest of the range like?  To find out, 'musings returned to brianandtrevors for an evening of Kudos discovery.  The evening followed a fairly typical approach for a joint dealer / manufacturer evening - gradually stepping up the range, but perhaps with a little twist tonight.  To allow the comparison of the speakers, a pretty much "no compromise" system was put together from Scottish manufacturer Linn:

A largely Klimax level LP12 - Radikal PSU (in the Akurate casework), Ekos SE2, Kandid and a booplinth.  Onboard was a Urika 2 phono stage which fed an Exakt signal to a Linn Klimax DSM acting as pre-amp and streamer.
Initially the KDSM ran with its internal Katalyst equipped stereo DAC to a Linn Klimax Twin/D stereo power amp.
I/C cables were Linn silvers, with Chord Music making sure there were no compromises on the speaker cable side.

That's quite some front end to feed into the first speaker we heard tonight - the diminutive little Kudos X2 compact floorstander.  Bear in mind that, at £1600, it was being fed by a system that included speaker cables that come in at (assuming they were 3m in length) 4x the price of the speakers.
It has to be said that these little speakers probably weren't designed for use in a room the size of tonight's dem room.  Before they were played, Kudos' Dave White introduced himself and the company philosophy - keep things simple and use the best quality components and cabinets that can be achieved at a price point.  Drivers all come from SEAS, modified or created to Kudos's own requirements.  So until the top of the range, simplicity means 2-way designs, uncluttered crossovers and quality cabinet veneers.  So the little boxes played and did a pretty good job.  Yes, there was a looseness in the bass, which goes surprisingly low, there was some vagueness in the treble but the music was flowing, feet tapping, even the room joining in with some modes didn't detract from enjoying what was going on.  It would be great to listen to these in a smaller room, where I'm sure they'd work pretty well.  We listened to a few tracks from the streamer then moved on with a 3x price jump to the middle of the range Super 20 speakers.

This is another 2-way floorstander, but around 850mm high and sporting significantly higher quality components.  Again the finish is superb with matched veneers on the baffles. Well, this was a significant step-up in the musical presentation to match the price change.  The SEAS tweeter in the S20 is several steps up from the X2 in terms of detail, definition, believability and control. Similar improvements come from the mid-bass driver. Curiously the initial impression was of a speaker producing less bass output than the baby floorstanders, but in reality its just hugely better controlled and keyed into the hooks and rhythms of the tune.  The treble presentation, whilst far more refined, is just a little to forward in the mix for my personal taste, but there's no doubt the others in the group of 12 were enjoying what they were hearing.

The next step up was 2x on the price-o-meter and takes us into Titan territory.  We didn't hear the 505 standmount tonight, going straight to the first of the floorstanders, the 606.  This is similar in height to the Super 20, but the cabinent is very differently constructed.  Dave introduced the isobaric mid-bass driver and the thin-walled inner cabinet which is surrounded by heavy MDF side panels that are connected to the inner panels with damping material.  The tweeter too is from SEAS's upper end Krescendo family, amended to Kudos spec - the tweeter alone costs more to Kudos than all the drivers put together in a pair of X2s.  They're very substantially built speakers, needing a trolley to move them around, even though they're still under a metre high.  And how was this?  Well, it wasn't all a complete step up from the Super 20.  Bass a little deeper, treble that much more clear and definitive in the way it starts and stops, vocals carrying more emotion, along with tighter imaging, most if it was good.  But for me the Super 20 won out on the bass lines keeping pace with the rest of the music, and providing that foot-tapping drive.  So not a complete success for me.  After a short break to refresh glasses, along came the "twist" of the demo.  The Kudos Super and Titan ranges have a little trick up their sleeves - they have a clever but simple connection panel on the rear that means they can be converted to work in active mode - that is, effectively removing the internal passive crossovers to allow power amplifiers to be connected directly to each drive unit with the splitting of the frequencies delivered by an active crossover in front of the power amps.  This works with Naim analogue active crossovers and with Devialet and Linn digital crossovers.

So the Klimax DSM changed its role from digital to analogue converter, to one feeding a still digital Exakt feed to a Linn Klimax Exaktbox/1.  The Exaktbox does the digital to analogue conversion, along with some clever stuff such as phase correction of the drive units (and no crossover phase distortion), time aligning the drive units and adjusting the speakers' output to counteract room modes that normally causes "boominess".  Because each drive unit now needs its own power amplifier channel, an additional Klimax Twin was pressed into action, along with more Chord Music speaker cables.  Now the Titans are singing. This is a massive step up in performance for these speakers, much as we've experienced before when hooking the Super 20s up to an Exakt system back at 'musings base.  The reservations with the 606 in passive mode are almost gone - there's still a little reticence in the bass lines, but its very minor now and allows the other elements to shine through.  The live Eva Cassidy track we started with on the X2s is now in a huge venue, the soundstage goes back a long way beyond the speakers, Eva's voice is full of emotion, inflections and phrasing details. Nice.  We listen to a good few tracks from the streamer. Interesting set of feet on the 606s tonight, seem to tackle some of the shrillness I've heard from these speakers when sitting on standard spikes. Other than understanding they have some Sorbothane de-coupling, there wasn't time to discuss further tonight.

Another break follows, and the final set up of the evening is rolled into the room whilst more wine, coffee and juice is sorted out for the audience of a dozen or so listeners.  In the break we swap system information, who's interested in what and why Kudos is of interest.  Most have Linn front ends of some sort - vinyl and streaming, there's a few Naim front ends (streaming and CD) mostly Linn amplification but also Naim and a few others.  From a speaker comparison perspective, Linn, PMC, Kudos and others are in use.

Back to listening and we're now at the top of the Kudos range with the Titan 808.  Unlike last time in this room, the 808 was not supported by the big REL subs.  They had to fend for themselves.  It turns out that they're quite capable of looking after themselves thanks very much, and I ended up enjoying them more on their own.  The sense of scale of the Eva Cassidy venue is stunning on the 808 and they punch hard and fast.  Unlike the 505, 606 and 707 which have slightly (intentionally) leaky isobaric chambers, the lowest bass driver, in its separate box, is a more conventional sealed isobaric.  The 808 is a 3 way design but described as 2.5 way by Kudos by which I think they mean the lowest bass driver augments the lower end of the mid-bass rather than delivering a completely separate set of frequencies.  So this top-end speaker needs 6x power amp channels and as such another Klimax Twin and pair of Chord Music cables were helping out in this final system configuration.  The same tweeter is featured across the Titan range yet it somehow seems clearer and smoother in this configuration, but its the clarity, transparency and realism of the mid-bass combined with the sheer kick and tightness of the lower bass that stand out here.  We listen to lots of tracks and the LP12 is pressed into action for a few songs, including an album by one of my current favourites, Bob Moses from Canada.  There was some boominess with this system, Linn's SPACE optimisation wasn't in use until later in the evening, after the formal presentation has been completed.

What did we learn?  Well, in passive form, mostly spending more gets a better result, but not always in all areas.  But once Exakt was deployed, the whole experience was a huge improvement in performance and consistency. And, yet again, the 808 produced a great result - personally I think they performed better than with the REL subs in this room - not quite so jaw-dropping in terms of sheer power and impact, but more musically satisfying.  The X2's are good for their price and did a reasonable job of filling the big room.  But then again there's no real substitute for box volume, driver quality, cabinet construction and, most importantly, a high quality front-end active system. It would've been nice to hear the Super 20 moving from passive to active, but you can't fit everything into one evening.  I do wonder about those in the audience who might've been contemplating the 606 - were they satisfied, or do they now spend a longer time saving for the 808?  But then again, there's the 707 in between, and that's definitely worth a listen. I won't be changing my Twenty.26s for the 606s as they didn't do absolutely everything comprehensively better.  Perhaps the 707s?  Will have to leave it until another time to find out.

Thanks once again to Brian, Trevor, Dave and the other attendees for another enjoyable and instructive evening.

Saturday 4 May 2019

Linn's Akurate Exakt DSM / System Hub - Adding Surround Functionality

Linn's Akurate Exakt DSM (AEDSM - the main source in the 'Musings system) has always had lots of HDMI inputs and an output, since it was launched in 2014.  Later versions and the otherwise identical re-branded System Hub has an updated HDMI board to support later protocols.  If I remember correctly, the update was introduced in 2016, but there must have been some forward thinking going on back then...

At the end of 2018 it became apparent that a surround sound upgrade was available to be retro-fitted to the AEDSM  / Akurate System Hub (ASH), for Exakt systems.  I would say "announced by Linn" but that would be overstating the case as the stealth marketing continues...

To add the new surround board, the later HDMI (2.0) board is needed - we'll see why in the pictures below.  So back in 2016 the board was designed with the ability to add a surround module which wasn't mentioned at the time.  So later AEDSM / ASH products can have the surround module added to the HDMI board already installed, earlier AEDSM products need an update to the HDMI board before the surround can be added.

But surround capability has been available for some time in Exakt right?  Well kind of - if you have a disk player or movie / tv streamer that can decode the signal and then send a multi-channel digital output for the AEDSM to translate that into Exakt and send it to multiple Exaktboxes or Exakt equipped speakers.  So the major change here is that it is possible to connect multiple sources to the AEDSM / ASH where the processing will be carried out inside the DSM, not in the source component.  Also, in previous Exakt surround implementations, as in stereo Exakt, an Exaktbox channel and a power amp channel is needed for every drive unit in every speaker.  Now it is possible to set up an Exaktbox to supply a full range signal to centre, rears and sub, whilst the main left and right channels continue with the normal approach to Exakt.  So that massively reduces the cost of going Exakt surround for those who already have Exakt main front left and right solutions.  For example, in a Linn Akurate system using a 225 centre channel, Akubariks as rears and a sub, and additional 13 channels of Exakt and power amplification is required.  And those Exakt channels would have to be across 2 full Exaktboxes and one Exaktbox sub.  Now those additional centre, rear and sub channels can be driven out of one Exaktbox and 3 amp channels (plus the sub amp).

This will be first of 2 (or possibly 3) parts - in the next I'll get to setting up the system, but for now, this is about the boards that are fitted into an early DSM to get surround up and running.  The pictures below show before and after:

Original HDMI board - The front of the DSM is at the top of the picture: 

It's not easy to spot in this picture, but there are 2x main board layers - HDMI is on the upper board - the lower board contains the pre-amp and Exakt boards.  This upper board ends where you can see the 2x light blue ribbon cables upper left

The Newer HDMI (2.0) Board.  Main interest here is the new long multi-pin connector in the centre of the board:

Surround Module Still in Anti-Static Bag.  It's quite a small unit:

Surround Module Underside:

Note the board copyright on the lower edge in this picture - its not a Linn designed board - it looks like a product of Momentum Data Systems based in California, US. No surprise that it would be an outsourced supplier - Linn won't want all the expense and complication of testing and managing the licencing of this kind of functionality - it changes far too frequently to make sense at Linn production volumes:  http://www.mds.com/wp-content/uploads/Datasheets/Audio/DAE82_rev8d.pdf  Looks like it may be a 4 year old design already.

Surround Module Installed into the Multi-pin Connector on the HDMI Board:

 Next post in this short series will consider connecting up the Exakt system implications.