Photo-electric pick-up cartridge and equaliser
Made by: Digital Stream Corporation, Kanagawa, Japan
Supplied by: Soundfowndations Ltd, Berks
Telephone: 0118 9814238
Web: www.ds-audio-w.biz; www.soundfowndations.co.uk
Prices: £18,995/£42,200 (cartridge/PSU & equaliser)

CARTRIDGEDS Audio Grand Master EX
How to upgrade the ‘ultimate’ optical pick-up? By fitting the Grand Master with asingle-piece diamond cantilever and stylus. We take the GM Extreme for a drive...
Review: Ken Kessler & Paul Miller Lab: Paul Miller

It’s too easy to presume, just because
only one change separates a newmodel from an earlier one, thatassessing it will be a breeze. DS Audio’s£18,995 Grand Master Extreme optical
cartridge differs from its stablemate solely
in its cantilever/stylus assembly. Asidefrom a different body colour for easieridentification, I wrongly imagined thata side-by-side shoot-out with the earlier
Grand Master [HFN Feb ’21] would suffice,and that a couple of LPs’ worth of listening
would reveal all. Silly me.
Actually, ‘assembly’ is the wrong word
because the whole point of the Grand
Master Extreme – pun intended – is that the‘Micro-Ridge’ stylus and diamond cantileverare formed as a single piece, manufactured
by Orbray (formerly Namiki Seimitsu).
This is a new trend in the high-end, withAudio-Technica and others offering similaralternatives to the traditional stylus-gluedin-place construction that has been thesole methodology for decades. Its goal
is to minimise even further any spurious
vibrations between the LP and the pickup tracking it. If this seems like a rather
picayune detail about which to concern
one’s design team, bear in mind that

Left: The solid alloy packaging and wraparound stylus guard ensure your precious
purchase is safe until you mount it into an arm!

half-century ago. The difference is that inthe 2020s we have LEDs that free cartridge
designers from the problems of heat andweight, thus enabling the creation of a true
optical cartridge without the burden of a‘hot’ lamp. Those original bulbs generated
enough heat to warm the damping rubberof a cartridge, softening it over time andchanging its compliance. While the makers
of early optical cartridges tried various
solutions, the technology was abandoned
before suitably tiny LEDs were readily
available, not least because digital was on
the horizon. As DS Audio states, however,
the optical principle is the same.

Lighting up
the activity in an LP’s groove is at a truly
microscopic level [see PM’s boxout, below].

Living the dream
For those not familiar with DS Audio
cartridges, they are the realisation ofa dream first manifested in Toshiba,
Kenwood and other optical cartridges of a

How it departs from the dozen or so othertypes of cartridge – moving-magnet,moving-coil, movingiron, moving-flux, etc(but not counting
electret, strain
gauge orotherFULL DIAMOND
While both ‘Grand Masters’ share the same dual-mono LED/
photocell, and decorative white LED at the front, it is theirstiffer diamond cantilevers and reduced moving mass thatmost clearly benefit their performance over DS Audio’sboron [HFN Dec ’22] and alloy-cantilever [HFN Oct ’21]
models. Although these optical designs are free of coils andmagnets the precise communication of information between
groove and – in this instance – beryllium shading plates [justvisible in the inset picture, right] faces the same challenges
as a regular MM or MC.
Ideally the pick-up’s cantilever/stylus would be bothinfinitely stiff and of vanishingly low mass. In practice thisis unlikely, but at least the EX’s one-piece diamond avoids
the extra mass of adhesive, and potential compliance, ofa joint between the cantilever and stylus. All cantilever/stylus combinations exhibit a series of bending and twistingmodes that interfere, or at least modulate, the motion of
the shading plate (or coils, or magnets) relative to the stylus

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in the groove. In-band
resonances with lowercost alloy cantilevers
are even employed to
strategically boost the topend response of some MMs! But
DS Audio is on a quest to achieve theopposite here and banish all unwanted
movement to far higher frequencies. Our response plots,
while following the same trend as the Grand Master,certainly look smoother [see Lab Report, p55].
The source of DS Audio’s one-piece wonder is revealed inour review, but Audio-Technica has also recently unveiled asimilar 0.22mm-square unified stylus/cantilever in its limitededition AT-MC2022. While a natural diamond cannot becleaved along faults into a 90o shape, A-T’s solution involves
a CVD (chemical vapour deposition) lab-grown ‘diamond’
that’s trimmed into shape with a powerful laser. PMexceptions) – is in eliminatingcoils and magnets in their
entirety. The two mostwidely-accepted types (MMand MC) generate electricalsignals via manipulation of amagnetic field, a current being
induced when a magnet orcoil moves. By the same token,
these designs are necessarily moresusceptible to stray electrical noise– compared to optical transducers,
they’re a swarm of bumblebees.
Of course, an optical cartridge still
has to trace the wiggles in the groove,
but, in the words of DS Audio, ‘it detects
music signals by capturing shadow changes(brightness changes) using LEDs andphotocells’. Here the cantilever is moving
neither coils nor magnets but a ‘lightshading plate’, a square of beryllium foilwith a thickness of only 100 microns, inresponse to the stylus’s motion.
In DS Audio’s cartridges,
this foil plate vibrates
in front of the infrared
LED, modulating thelight level that falls on
the photocells behind
and, thus, the voltage
flowing across them.
The company’s top-flightpick-ups use separate LEDs,
shading plates and photocells
for the left and right channels,
improving both output, S/N ratio and left/right stereo separation.
Because DS Audio’s photo-electric
conversion is sensitive only to theamplitude of the movement of thestylus, unlike velocity-sensitive MCs/MMs
whose output increases with both groove
excursion and frequency, the Grand MasterEX requires only a relatively subtle HF boost
to realise a ‘flat’ response with all RIAA preequalised LPs [see PM’s Lab Report, p55].
So while DS Audio’s various optical pick-ups
can be mixed-and-matched with its rangeof PSU/eq boxes, none are compatible withtraditional phono preamps (and vice-versa).

Counting the cost
Now we arrive at what must represent
the current state-of-the-art for optical
cartridges. The Grand Master Extreme canbe purchased in a package with the twobox Grand Master Equaliser for £55,075, asaving of around £5000, as the equaliser
is sold separately for £42,200. The Grand
Master cartridge remains in the catalogueat £12,550, and existing owners wanting
to upgrade to the EX model can benefit
from a 20% discount.

Here’s where you can also
save money, if it matters at
this level. It has been myexperience with six different
DS Audio optical cartridges
and four energisers that thelatter, while offering audible
differences, contribute lessto the performance than do
the cartridges. I even tried theGrand Master Extreme with theentry-level DS-E1 energiser [HFN May’19] at £1270 and you could still hear how
it bettered the Grand Master.

Ahead of the curveThis brings us to the only question thisreview begs: does the Grand Master
Extreme improve on the Grand Master?
So vivid were the gains, despite nearly
identical measurements and my initialdisbelief that something as
seemingly minor as a singlepiece stylus/cantilever could
up the performance over a
glued-in stylus, that I spent
disproportionately more timeassessing the Extreme than
I had initially expected toallocate to a mere change indiamond fitting. Or the removal thereof.
It required a varied mix of genres
because it wasn’t just a case of smootherbehaviour, as PM pointed out upon
revealing that the curves were nearly
identical. The original Grand Master
cartridge is already a ‘smooth’ operator
and I found nothing in its behaviour that I
thought might need taming, polishing orrefining. Opening with Albert King’s Born

ABOVE: Threaded holes in the GM’s alloy bodyallow it to be bolted tight, but the shallow
profile requires care in adjusting the rear arm
height. The EX model is distinguished by its gold
body and one-piece diamond stylus/cantileverLeft: Micrograph reveals the laser-trimmed
diamond cantilever with right-angled tip cut
into a ‘Micro-Ridge’ profile

Under A Bad Sign [Craft/Stax CR00513], I
was struck not so much by the timbre of
the guitar and its fluidity, the veracity inthe reproduction of his rich, deep voice,nor the absolutely mesmerising punch of
the Memphis Horns. Instead, I was bowled
over by even more taut bass – with noincrease in aggression – and a soundstage
so cavernous as to challenge my all-timereference, the Denon DL-103 [HFN Jul ’09].

Massive attack
I should add here that, even with the Grand
Master Extreme’s supremacy exhibitedat such an early stage inthe sessions, part of me
stayed grounded enough toacknowledge that its hyperprecision and the nakednessof the sound might not suitevery listener nor everysystem. But can a cartridge
be too revealing? Purists,transparency addicts and those who dreamof master tapes might say ‘No!’, but I am
reminded of Peter Lederman’s guidance
when advising his customers as to whichSoundSmith strain-gauge cartridge [HFNMay ’21] will suit their system.
At a certain level, you need a systemthat can handle the information: attack
bandwidth, dynamics, what-have-you. It
is the reason why I have not abandoned‘It adapted
like a Lotus
moving fromroad to track’

www.hifinews.co.uk | Reprinted from Hi-Fi News for global distributionCARTRIDGE
Tetsuaki Aoyagi

SoundSmith’s Hyperion, the various Koetsus
and Londons/Deccas, which I use as themood strikes. And because King’s album is
one I have owned for over a half-century
and have played at least 200 times, I wasstunned by the Grand Master Extreme’sability to extract even more from thegrooves. As with the changes in the curves,the gains were minuscule but inescapable,
the precise sorts of nuances which
separate two vintages of the same wine (oreven two bottles from the same case).
How much of this was due to what mytiny earth brain attributes to the Extreme’squietness, and thus its refusal to mask
low-level information, I cannot say. But
when I moved on to Son House’s far leaner,utterly minimalist Father Of The Folk Blues[Analogue Productions/Columbia CS9217],

ABOVE: Machined, bead-blasted and anodised
casework hosts the over-sized Grand Master PSU[bottom] and energiser/equaliser [top]. They are
chunkier than many high-end power amps!

which features only voice and guitar forthe bulk of the album, I was able to focus
on his metal slide’s contact with the strings
and the textures in his vocals, with noother distractions.

Ready to rockIf one’s yardstick for system performanceis the sensation of placing the artist in thespace in front of the listener, the Extreme
has very few peers. While I always seem tomake reference to Denon MCs when this
aspect of playback is discussed, a welltuned Decca or Urushi-lacquered Koetsu[HFN Jun ’13 & Nov ’19] is also ‘upthere’. What the EX showed, evenwith this uncrowded session, wasboth width and depth, but that
only meant the sense of air. For
scale, I needed majesty.
Whitesnake’s remastered
Slip Of The Tongue [Rhino0190295409784] is one of thosejoyous contradictions in which aneardrum-bursting band actuallycares about sound quality. While
my go-to heavy metal/hard rockartists are Mountain, Cream andBlue Cheer, this band’s time with

Allegiance to LP playback issomething of a mission for thatindefatigable champion of optical
cartridges, DS Audio’s President,
Tetsuaki ‘Aki’ Aoyagi. ‘I intend topursue the reproduction of analogue
records as can only be done with
optical cartridges’, he promises. Ofcourse, this latest twist in the DS
Audio saga – the Extreme’s singlepiece diamond stylus/cantilever – isan ‘on trend’ approach in high-end
cartridge design [see boxout, p50].
‘I have learned’, says Aki, ‘that thesound changes so much dependingon whether the stylus is glued ora single-piece. I would also like tomake the vibration system lighter toretrieve the stylus tip information
more directly’. Research continues
beyond the stylus/cantilever but
some aspects of the cartridges’
basic optical topology seem settled.
Regarding immunity from straylight, Aki says, ‘The photodiodes are
only sensitive to infra-red (850µm)
rays, so interference from outside
light is basically not a problem. Also,
the cartridge’s body shell prevents
light from coming in from the sideor top’. There is, however, in-depth
research being conducted into theoptimisation of the light path.
‘We are now experimenting withalternative light sources and photodetectors for possible future use.
We will probably not change thewavelength, but there are various
options, such as using a lens to focus
the light to a more stable intensity.
We are also looking at using photodetectors that offer faster response
times and lower [thermal and shot]noise.’ Watch this space!

LEFT: Gold-anodised plates inside
the GM equaliser connect the six
huge electrolytics feeding each sideof the fully discrete, fully balanced
filter and output stage [far right]

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Labreport
DS Audio GRAND MASTER EXABOVE: Rear view of the PSU [bottom] and equaliser [top]. The pick-up’s internal LEDs
are powered via the R– and L– pins while the output is returned via R+ and L+, all via
the ‘Input’ RCAs. Three eq’d line outs, on RCAs and balanced XLRs, offer three bassroll-offs from two different – 30Hz and 50Hz – turnover freqs. [see Graph 1, opposite]

guitarist Steve Vai provides ample
opportunity to assess the sheer massof a recording. Vai’s pyrotechnics arealso ideal for gauging the attack oftransients, while the vocals are outof the stadium filler’s handbook.

Extreme epiphany
This album offers the kind ofcontrast that fastidious listeners andaudio veterans relish: as far removed
from Son House as possible,
Whitesnake’s massed instruments,
with so much going on, enabled theExtreme to demonstrate its prowesswith a different sort of challenge.
I am not suggesting for a second
that House’s one instrument andvoice is easier to reproduce than an
onslaught from a big hair band, but
the Extreme adapted to it as easily
as a Lotus moves from road to track.
There’s usually a moment of
epiphany when one track tells you all

you need to know. Even after goingfrom electric blues to acoustic,
followed by hard rock and with anumber of genres inbetween, it was
a 34-year-old country LP that mademe fall in love with the Extreme:
Dwight Yoakam’s Just Lookin’ For
A Hit compilation [Reprise 759925989-1], an exemplar of a genre
which was out of fashion when hearrived in the 1980s.
What it does for assessing hi-fisystems is deliver a ton of ‘redneckbass’; that deep, snapping, funkylower register, underlining slightly
nasal vocals, as if ol’ DY was doing
an impression of ol’ Buck Owens.
Now this music might seem more
at home via an 8-track player in a
pick-up truck but, hot damn, it mademe forget all about the system andspoke directly to my inner cowpoke.
DS Audio’s Grand Master Extreme
is that kind of cartridge. It shouldcome with a warning: you need tobring plenty of food and drink into
your listening room because you will
not want to leave.

HI-FI NEWS VERDICTABOVE: The GM EX’s pins are clearlymarked and separated. Just visible are
the shading plates, diamond cantileverand Micro-Ridge stylus [see also p51]

Despite my adoration of Decca,
Soundsmith and Koetsu pick-ups,
HFN Feb ’21 saw me write, ‘The
Grand Master is so truly supremein resolution, transparency,
spatial recreation, neutrality andany other parameter I can namethat it’s impossible for me to notsay what I usually try to avoid:“This may be the best cartridge
I’ve ever heard”’. This time, I
cannot deny: the Grand Master
Extreme is even better.

Sound Quality: 92%
0-------- 100

Bearing in mind that this ‘Extreme’ version of the Grand Masterflagship [HFN Feb ’21] is distinguished only by its one-piecediamond stylus/cantilever [see boxout, p50] then the measurable
differences depend as much on the sample-to-sample production
variation of the shared photo-electric mechanism. In practice
the precise matching of its 22o VTA and 11/15cu complianceis remarkable in itself, the latter playing a significant role indetermining the tracking prowess of these pick-ups. Both GrandMasters will hold onto the maximum +18dB test track (re. 0dB at
315Hz/5cm/sec) at a 2.0g downforce, albeit at ~1.5% THD.
Once again, the 2.05V output (re. 1kHz/5cm/sec) is afunction of the GM equaliser as are the six ‘bass contours’, threerolling off from a notional 50Hz and three from a lower 30Hz.
Output 1 [see pic, left] provides a +3.6dB/+1.9dB boost at20Hz in 30Hz/50Hz settings [black/grey traces, Graph 1], while
Output 3/50Hz (–4.4dB/20Hz) is arguably the ‘safest’ with big,reflex-loaded speakers. Channel balance, incidentally, was a far
tighter 0.1dB with our sample of the EX. Otherwise the boosted
and extended HF response of +5.5dB/20kHz [–8dB re. 5cm/sec; dashed HF trace Graph 1] marks out the GM and GM EX
as the most advanced in DS Audio’s stable, but note how theEX’s response is visibly ‘smoother’ than the GM’s. The extended
bandwidth is also reflected in the 4-5% stereo THD peak being
pushed out from ~7kHz to 9kHz here [see Graph 2, below] while
the excellent lateral/vertical symmetry is clear from both theresponse and THD plots [solid black and red traces/infills]. PM

ABOVE: Freq. resp. (–8dB re. 5cm/sec) lateral (L+R,black) vs. vertical (L–R, red) vs. stereo (dashed). Bass
only: Output 1/30Hz, solid; 2, dashed; 3, dotted;
Output 1/50Hz, grey solid; 2, dotted; 3 dashed)

ABOVE: Lateral (L+R, black), vertical (L–R, red), stereo(dotted) tracing and generator distortion (2nd-4thharms) vs. freq. from 20Hz-20kHz (–8dB re. 5cm/sec)

HI-FI NEWS SPECIFICATIONSGenerator type/weight

Photo-optical / 7.7g

Recommended tracking force

20-22mN (21mN)

Sensitivity/balance (re. 5cm/sec)

2050mV / 0.1dB (from Eq unit)

Compliance (vertical/lateral)

11cu / 15cu

Vertical tracking angle

22 degrees

L/R Tracking ability

80μm / 65μm

L/R Distortion (–8dB, 20Hz-20kHz)

1.2-6.7% / 0.3-5.8%

L/R Frequency resp. (20Hz-20kHz)+3.6 to –1.1dB / +3.6 to +2.1dB

Stereo separation (1kHz / 20kHz)

34dB / 25dB

www.hifinews.co.uk | Reprinted from Hi-Fi News for global distribution