LINN Exaktbox-i: Photo Comparison Between Majik (Pre-Katalyst) and Akurate Katalyst Versions

Linn's carefully hidden Exakt separates system consists of the following key components:

An "Exakt ready" streamer / pre-amp (such as Klimax DSM / Akurate System Hub / Majik DSM amongst others)

A proprietary Exaktlink cable which uses standard Ethernet cables

An Exaktbox which is essentially a digital active crossover and digital signal processor, amongst other things (such as Akurate Exaktbox10 / Klimax Exaktbox)

Power amps, which can be from Linn or any other manufacturer.

However, there is an option to combine the last 2 elements - the Exaktbox and the power amps.  This is called an Exaktbox-i and combines 8 channels of DAC / digital active crossover and 8 channels of power amplifiers in Linn's normal just-a-bit-narrower-than-standard box.  There's really only one of these in the range, but it has evolved in the 4 or 5 years it has been available:

1 - Intitially it was a Majik Exaktbox-i containing Majik level DACs and 100W power amps, all in the Majik level casing

2 - Then it was re-badged the Akurate Exaktbox-i but still contained Majik level DACs and 100W power amps, but now in the more substantial Akurate casing.  This version was very short lived, soon replaced by:

3 - Akurate Exaktbox-i with Akurate level Katalyst architecture DACs but sill with Majik level 100W power amps in Akurate level casing

As is often Linn practice, those who bought the earlier products don't get left behind when there's an upgrade.  So it is possible to have a Majik Exaktbox-i upgraded to Akurate Katalyst Exaktbox-i internals but retaining the Majik casing.  The first Akurate Exaktbox-i can also be upgraded but I expect most of those were done pretty much automatically as there was a deal where the cost to upgrade was only the difference in price between Katalyst and non-Katalyst versions.  It would be very odd to find one of these that hadn't been upgraded, given the small price to do so.

I've been using an original "pre-loved" Majik Exaktbox-i for a while for Exakt filter design activities.  For some reason, now seemed to be the right time to take that up to Katalyst specification.  So that has allowed me to make comparisons between the circuitry of the non-Katalyst and Katalyst versions.

A similar comparison of the Akurate Exaktbox10 (April 2018) is here.

Much has been written about the musical capability of the upgrade from Linn's previous generation DAC to the Katalyst DAC, and I can't think of anyone who has anything but praise.  An example is here regarding the upgrade in Linn's onboard active Akubarik speakers.  So I'll not write about that here as it is well trodden path. With the upgrade being applied to the Exaktbox-i back at the Linn factory, there's no ability to directly compare the 2 products back to back.

To the photos.  Note that every single audio board (DACs are combined with the power amps) and the Exakt processing board are changed in the upgrade - the photos with the green circuit boards are the Majik non-Kat version, the black circuit boards are the upgraded Kat version.  The PSU and the casework is untouched, save for the addition of a Katalyst sticker on the underside.

Externally the box is unchanged

BEFORE AND AFTER UPGRADE COMPARISON PHOTOS:

The most obvious difference from an overall perspective is the change from green to black and gold boards

Each side of the enclosure has 4 channels of power amps (the chips bonded to the heatsink are the obvious components) and 2x stereo DACs.  The DACs above are the cross-shaped cluster of an oblong chip surrounded by 8 smaller chips

Here you can see the difference in the DAC architecture - now we have the 2x stereo DACs which are the 2x flat square chips - the board layout is very different

The "flyover" board down one side of the enclosure is the Exakt processing board.  The above original layout has 3x FPGA processors - the large flat square chips. The one on the left is the "master" processor with the other 2 processing 4 channels each

On the new board there is one more powerful FPGA chip in the centre doing the work formerly done by 3x separate chips

Board labelling for channel 5 to 8 DAC / power amp board has been relocated

Relocated labelling for the Exakt board

The increased complexity and density of the components surrounding the DACs is clear in this comparison.  The Katalyst DAC has multiple different regulated power supplies which probably explains this increase in components

SOME KATALYST ONLY PHOTOS:

Xlinx FPGA that does all the Exakt processing

DACs and power amps for channels 1 to 4 live in the shadow of the Exakt board

***POSTPONED*** THE Enthusiast's Hifi Show - The Alternative To The Commercial Shows - 15th March 2020

THE WAM SHOW AT KEGWORTH ON 15TH MARCH 2020 HAS BEEN POSTPONED.

Please keep an eye on www.thehifishow.com for updates.


The time of the year that many in the Hifi communities look forward to is almost upon us.

How about a Hifi Show that offers:

- Over 45 systems to listen to
- Every one of them unique
- No manufacturer rooms
- No dealer rooms
- Only room upon room of enthusiasts playing their own systems
- Where you're encouraged to choose the music or bring your own
- Where you can chat Hifi and music without being sold to

Well, that's exactly what The Wam Show is all about.

This year it's at Kegworth again - a reasonably central location which has decent sized rooms along with pretty solid floors and walls.

Kegworth Hotel and Conference Centre
Packington Hill
Kegworth
DE74 2DF
UK
15th March 2020 from 10am

https://g.page/kegworthhotel?share

More details are at the show's website:

thehifishow.com

Audiophile Musings will be there again this year.  We'll be playing a Linn Akurate Exakt Katalyst active system with Lejonklou power amplification.  Speakers will be Graham Audio LS5/9 (modified) and this will be the first public playing of them on the end of a Linn Exakt system.

See you there!

Previous reports:

2019
2018
2017
2015 Part 1
2015 Part 2
2014
2013

NAIM SBL Loudspeakers: From SNAXO Active to Linn Exakt: Guest Contributor

Here's something a little different.  The first ever "guest contributor" post on AudiophileMusings.  Below is Clive Gidney's experience of working with SpeakerFilters on development of Linn Exakt filters for the Naim SBL loudspeakers.

Full disclosure: the lead designer at SpeakerFilters is also the "editor at large" of AudiophileMusings.  Note the article below is entirely Clive's own words without any edits.  Enjoy, and thank you Clive for your contribution.

NAIM SBL: FROM SNAXO ACTIVE TO LINN EXAKT by Clive Gidney

At the beginning of the year, having been running a pair of SBLs with a pair of 250s sort of bi amped (one for left channel only & one for right - just because I had 2 x 250s & hadn't got round to swapping them for a pair of 135s) I decided that it was time to do the proper thing & go active. 
 
 
 
 So SNAXO  & Supercap added and this gave a significant improvement in detail, soundstage, PRaT & all the things that SBLs are famous for... But I was still left with the feeling that they are a bit forward & a bit bass light. In fact a non audiophile friend described them as "a bit shouty".  And yes - I'd done all the set up things, as close to a solid brick wall as the skirting board would allow, re-sealed the bass loading box etc.
 
Then a couple of months ago I was at Brian & Trevor's in Manchester for a musical evening  listening to a Linn/Kudos Exakt active system thinking this system sounds amazing (although I would have liked to hear it with Naim power amps) but the transparency that the Exakt technology brought, which performs the crossover in the digital domain, was breath-taking. In the interval I remarking to one of the other attendees how great Exakt was & that I wished it was available for SBLs! And he said "I write Exakt filters for speakers that Linn doesn't support" OMG!! That person was Neil Hallworth of speakerfilters.com
 
So we embarked on the Exakt SBLs project.
 
Step 1 was to physically measure the SBL cabinets, the position of the drive unit centres, the front baffle slope etc. These numbers were then plugged into Linn's system to enable Linn's Space Optimisation to be enabled. That is available now for free for anyone using a Linn DS or DSM with SBLs via Konfig! 
  
Step 2 involved Neil calling at my house to take some electrical measurements of the drive units to measure their impedance.
 
Step 3 Neil then took these measurements together with some information on the crossover frequencies & slopes obtained from Naim to work some digital magic to create a first cut of the digital Exakt crossover filters. In fact he sent me three versions with different crossover slopes, 2nd order, 3rd order & 4th order. It was very quickly apparent that the 3rd order (which is what Naim used) was the best. The 2nd order sounded congested in the mid-range while the 4th order sounded as though there was a hole in it. He then sent me a 3rd order v2 without telling me what he'd done. When I tried it, it was clear that this was an improvement over v1 with better definition & spatial separation. The sound stage was more clearly defined & I was in heaven. The slightly bright & comparatively bass light presentation was gone without losing any of the strengths of musicality & PRaT that SBLs are renowned for. Neil assured me that there would be more to come in step 4 but I was so impressed that my SNAXO & Supercap were already up for sale!
 

 
Step 4 Neil called again to fine tune the filters. Firstly we agreed that in taming the brightness, they had lost a little of their sparkle. Now apparently, the sound waves emanating from all drive units have an interaction with the speaker cabinet front baffle and to compensate for this, within the Exakt crossover Neil had created a 0.8 dB treble filter. Now I'd been advised by John Jackson (ex Naim Senior Test & Service Engineer & currently Witch Hat Lead R&D Engineer) that the SBL cut away foam grill was designed to overcome the treble baffle interaction issue. So Neil removed the filter, updated the Exaktbox & sparkle was back. Hi hats shimmered, room acoustics were tangible, the space around instruments & performers improved. 
 
Next we played with the actual crossover frequency. With v1 the bass/mid roll off & treble roll on were at the same point 2.4khz which we'd got from one Naim source. In v2 the bass/mid was rolled off at 2.3khz & the treble rolled on at 2.5khz (from a different Naim source) So we tried widening the gap by 50hz either way - not as good. Leaving the bass/mid where it was but bringing the treble back again - immediate improvement!
 
Adding baffle filters for the bass/mid drivers for both the length & width of the cabinet added further improvements and the subtlety  of the changes that could clearly be heard was mind blowing;  -0.5 dB - too much, - 0.25 dB, not enough so we settled on - 0.4 dB. Adding a 1.5 dB lift in the bass from 0-60 hz - too much, 1.2 dB - still too much, 1.0 dB - bingo! In all we went through 17 variations fine tuning the Exakt crossovers in just over two hours. Imagine trying to do that with resistors & capacitors in the analogue domain!
 
The end result? Absolutely stunning. If you thought going from passive to active with a SNAXO was a big step... from SNAXO to Exakt is like having seven league boots on! Really, it's that good. 
 
Oh, the cost?  Well  I'm going to make a few assumptions. If you're already active with SBLs, then presumably you've got a good front end - LP12 around Akurate spec, a Naim NDX minimum, maybe NDS, or a Linn Akurate DS/DSM Katalyst, Naim 82/Supercap or more likely 52/Supercap, SNAXO / Supercap.
Hardware. You keep whatever power amps you're using - in my case a pair of olive Nap 250s which will retain your signature sound. Ideally you'll need a Linn Akurate System Hub which becomes your pre amp - £2700 new or about £1600 pre owned, & a Linn Akurate Exaktbox Katalyst which is where the majik happens (see what I did there) - £5000 new or I picked one up pre owned with 4 years warranty for £3200; And, you'll need a set of  Exakt filters from speakerfilters.com  which are just £295. These  can be tested for a free 2 week  trial period before purchase. Total cost  about £5400 pre owned or ~£8000 going new
But you can recoup say £1500 on your NDX, or £2000 on your Akurate DS, £2000 on your 82 /Supercap & £1500 on your SNAXO /Supercap = £5/5500 so approx. cost  neutral going pre owned And if you've got a 52 or an NDS you might even have some cash left over


A huge shout out for Neil of speakerfilters.com for all the work designing & refining the filters. 

Clive. 

Musings At The HifiWigwam Show 2019

Room 120 is all ready for visitors tomorrow at the Wam Show at Kegworth.

www.thehifishow.com

After setting up and working on speaker positioning, the room was measured and SPACE Optimisation applied.  Linn Akurate Exakt source and Lejonklou power seems to be working well with the Gauder Akustik speakers.

Some independent feedback from around the forums:

Lejonklou forum member u252az: "Sunbeams system was the first Exakt system I have enjoyed - worth going just for that"

CyrusUnofficial forum member hifinutt: "Gauder sounded superb . Very natural" and on AOS "my favourite was the gauder akustik"

CyrusUnofficial forum member Czechchris: "I too liked the speakers you had playing"

The Flash: "sounding nicely balanced in that system. I think the curved cabinets are very smart indeed. The blue was far less of a "statement" than I expected, looked rather smart I thought."

Nopiano: "I agree with all the praise. They were evidently extremely well set up, and the system had a coherence and balance that was way beyond what I’d expected. Easy to enjoy!"

Richard A: "I’d like to add my plus one to those comments and this was my first chance to listen to Gauder. I loved the sound in your room, possibly the most natural/unforced of them all. I don’t need more speakers but I’d buy those in a heartbeat if I did. GLWS those are a bargain."

Inside Linn's Akurate Exaktbox - With and Without Katalyst

Photos below of the boards inside Linn Akurate Exaktbox10.  Click on an image for a larger version.

First the original version...

An extremely busy board with 10x mono DACs and (top left) 3x Exakt processors

3x Exakt processors (1 Master, 2x Slaves)

DAC layout - staggered on the circuitboard to fit them all in

Boards back to back and empty chassis...

New board at the bottom - a much simpler and clearer layout, but 5x stereo DACs rather than the original 10x mono DACs

Bare Chassis

Then the upgraded "Katalyst" versions (Akurate Exaktbox10/1)...

Much more spacious layout - 5x DACs in stereo mode.  Remembering, also, that Linn has just invested in a new board populating machine that places even tinier surface mount components.

Smaller board, less clutter

New, single, much more powerfull Exakt processor

Less crowding, but stereo rather than mono DACs

The proof is in the sticker.

EDIT 16 June 2018.

And here are the Akurate Exaktbox 6 equivalent photos:

The original Akurate Exaktbox 6 board in situ.  Note 6x individual DACs

Another view of the original board

The original board removed from the casework - the Exakt master and slave processors are bottom right

 Below you can see how much simpler the board layout has become.  There many fewer components mainly due to the use of 3x stereo DACs rather than 6x monos DACs.  Also, there is now only one Exakt processor which is more powerful than the previous 2 processors combined.
Of course, Linn's new board populating machines also place much smaller surface mount components which adds further to the spacious layout of the board.

New single, more powerful, Exakt processor top left

The 3 stereo DAC circuits are clear to see here, arranged top to bottom from just left of centre over to the right.