March 2022

WWW.HIFINEWS.CO.UK

6ea5rsyof Produsc&t
Review sFeature

World Exclusive

D’Agostino
unleashes theRelentless Pre

L ICO

NW

NYVI

REVIE

de la soulThorens
TD 1500

3 feet high…

Classic deck reborn
INVESTIGATION

Follow that...
14 best ‘difficult’second albums

MC Verismo

Ortofon’s titanium‘Exclusives’ moving-coilPortablepleasure

PLUS...
HiFi Rose RS201 E;
SA Legend 7.2;
Roksan Attessa
Streaming Amp;
Moonriver 404 Ref.
& Kimber Naked

Astell&Kern’s CA1000
DAC/headphone amp• OPINION 12 pages of letters and views • VINYL RELEASE West Side Story (Original Cast) on 180g LP• CLASSICAL COMPANION Hans Abrahamsen’s 70th birthday celebration • STUDIO TOURS Capitol• VINTAGE REVIEW Philips’ 1970 GA 202 turntable • READERS’ CLASSIFIEDS Hi-Fi bargains galore

001 Mar_22 Cover_v8_PMJR.indd 1

UK £5.99 Aus $15.99

01/02/2022 10:46

Dual-mono preamplifier with outboard PSU
Made by: D’Agostino LLC, Connecticut, USA
Supplied by: Absolute Sounds Ltd
Telephone: 0208 971 3909
Web: www.dagostinoinc.com; www.absolutesounds.com
Price: £159,500

PREAMPLIFIER

LEFT: Chassis are milled fromaerospace aluminium while
the rotaries are fashioned fromcopper-plated brass to give thevolume control some ‘heft’. Alllogic/PSUs are in centre chassis

D’Agostino Relentless Preamp

Designed to fit into thecentre chassis, the Digital
Streaming Module (DSM),
however, is nearly ready,possibly soon after you readthis, priced at £15,950. As
such, the DSM will remaincompletely isolated fromthe analogue preamplifier
circuits. It is fully-balanced,
with one DAC per channel,
claiming to support
768kHz/32-bit LPCM,
DSD256 (network) and up
to DSD 512 (USB-B). It willaddress Tidal, Qobuz, andSpotify streaming services
via a custom iOS app, withUSB, optical, coax, Ethernet
and Wi-Fi connectivity, as
well as Roon certification.

It’s taken three years, but it was worth the wait: D’Agostino’s Relentless Preamplifier
has arrived, and it’s as much of a revelation as the matching power amplifiers
Review: Ken Kessler & Paul Miller Lab: Paul Miller

You gotta love items with absolutely
perfect names: ‘Land RoverDefender’, ‘Rolex Explorer’, ‘Fender
Jazzmaster’. When founder andchief engineer, Dan D’Agostino, dubbedhis assault on the high-end ‘Relentless’,
with cost-no-object flagship monoblockpower amps [HFN Mar ’20], he might havebeen referring to himself, as that is how heapproached the task. With this matching
three-chassis Relentless Preamplifier(£159,500), he’s raised the bar once more.
Yes, it is again all about bar-raising. The
power amps elevated solid-state, highpower performance to levels so utterlyinconceivable that the usual topics ofaudiophile debate were thrown out alongwith any concessions to size, weight, hi-fi
fashion, or biases [see PM’s boxout, p41].
Aside from a choice of black or silver, bothwith copper accents, Relentless is aimed
at clients who accept unreservedly Dan’sbalanced-only dicta. As I said: relentless.

desired. Each button on the centre PSU
and logic section also lights up in different
colours to indicate source, zone, mute orother functions.
Cleverly eschewing cabling between
the three sections, the two mono preampchassis form a sandwich with the power
supply/control section inbetween. Theinternecine communication is a nifty party
piece: spin either unit’s copper rotary tochange level and watch the needle on theother respond in step. Balance is adjusted
by holding one while turning the other.
Here’s how they stack: each chassis
has four round metal feet that nestle into
circular apertures in the top surface of thechassis beneath. Two of the front left feetcontain interlocking gold-plated 30-pin
aerospace connectors to communicate
with the unit above or below – these carrylogic commands only, not audio.

HAUTE CUISINEFor the Preamplifier, the recipe is the same:over-engineered, hugely heavy, and bravely– for domestic audio if not for studioapplications – XLR-balanced-only. Of course,
phono-to-XLR adapters do work, should you
have a much-loved, RCA-only CD player, etc.
At first sight in the HFN demo room I
thought the top and bottom chassis of
the three-box stack were power supplies.
It was those massive meters on each,styled after Breguet pocket watches of thelate 18th century, the big ‘moon’ handagainst a round, illuminated display withrotary bezel. But these are the ‘left’ and‘right’ channel preamps, and the dials aresynchronised volume controls. The lightingchanges colour or flashes depending on
the function, with deep green by default,
red if phase-inverted, flashing red for mute,etc. They can be switched off entirely if
RIGHT: Inside the PSU/logic enclosure (centrechassis, p41) with regulated supplies for digital[left] and analogue [right], and comms bus[centre]. Streaming module will sit in the void[near left]. Note remote Bluetooth receiver [top]Reprinted from Hi-Fi News for global distribution | www.hifinews.co.uk

Another useful feature, especially asdeep-pocketed owners are likely to havecommensurately grand homes, is its ‘Dual
Zone’ functionality. This provides not justtwo playback zones, but independentsources for each. You can listen to a source
in one room, while playing something else
entirely in Zone 2. Ordinarily, either volume
control will adjust levels in the main room
(or Zone 1). When two-zone operation
is employed, the upper volume control
manages Zone 1, while the lower chassis’
volume control adjusts levels in Zone 2. I’dhope the second zone would be poweredby a brace of Relentless monoblocks, too...

BLUETOOTH REMOTE
Although the new Relentless remote [p45]
was not available to us, all of the functions
will be accessible through it. This controller
features a touch pad, while Bluetoothconnection eliminates range and line-ofsight restrictions. Adjustments made on
the Relentless Preamplifier’s panel(s) are
fed back to the remote control’s display
screen, including input, volume, andbalance selections.
Alongside the familiar 12V trigger
and software update connections,additional DC outputs are included[see p45] to service a forthcoming
phono preamp and other potential
additions to the Relentless range.

Dan D’Agostino told HFN that work has
not yet begun on the phono stage but, ‘We
have some interesting concepts I am eager
to explore for this future product’.

ULTIMATE POWER
The natural partner for the Relentless
Preamp? The Relentless monoblocks,of course [see p39]... These quarter-tonne
behemoths were first seen and heard at ourUK Hi-Fi Show Live in 2019 and graced our coverexactly two years ago [HFN Mar ’20]. The experience left its mark, although themassive rollercoaster of a sound was seemingly all the more visceral, gripping andspatially adventurous when partnered this time around with Wilson’s fabulous
Alexx V floorstanders [HFN Jan ’22] and the newcomer Relentless preamp, alllaced with Transparent Audio’s Gen 6 interconnect and speaker cable.
Two years on and Hi-Fi News remains the only hi-fi resource to have tested theRelentless monoblocks. In short, this amplifier is the most powerful and loadtolerant in current hi-fi memory, besting even Musical Fidelity’s Tri-Vista kW [HFNAug ’03]. D’Agostino quotes 1.5kW/8ohm, doubling to 3kW/4ohm and 6kW/2ohm
although we obtained a slightly higher 1.61kW/8ohm and lower 2.73kW/4ohm.
Moreover, under dynamic conditions, its massive PSU serves up 1.74kW, 3.35kW,6.36kW and 11.33kW into 8, 4, 2 and 1ohm loads, respectively – equivalent to106.4A (10msec at <1% THD)! However you look at it, the Relentless amplifiers
will surely drive any high-end loudspeaker with unwavering confidence. PMTRANSCENDENTAL
If you find the following notion specious,
please forgive me, but I’m convinced thatexperienced listeners know within mere
seconds what a component, systemor even a new LP or CD
sounds like in termsof quality, presuming
the system is burnedin and warmed up, ofcourse. What brought
this home in force
were the first few
notes of Booker T. &The M.G.’s’ ‘Soul Limbo’[Stax Gold – Hits 1968-1974;
Stax CDSXD 043]. They possessed such
ineffable presence that I wished I could goback and praise the Wilson Alexx V [HFN Jan’22] – still in situ along with D’Agostino’s
partnering Relentless monoblocks [see p3and p39] – with even greater fervour. Thebottom end (and I am no bass addict) was
so truly visceral and free of artifice or grainthat I was transported back a month toa live concert, where I sat as close to theorchestra as I was to these speakers.
It wasn’t just the realism of the sound.
Clearly, both Wilson CEO, Daryl Wilson, andDan D’Agostino are disciples of the belief in
the importance of soundstage recreation,and how correct physical placement of
the sounds and their dimensions impact
on tonal qualities. With stereo playback,you can’t have one without the other.

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

DAN D’AGOSTINO

The uncanny element imparted by these
Relentless amplifiers was a sense that, inthe best possible way, the performancehung in space independent of the speakerlocation. Simply, the system disappeared
and the scale was realistically large.

SUSPENDING BELIEF
Given that those first few moments showedme enough about the system’s soundstage
capabilities, confirmed repeatedly fromtrack-to-track, it was a 68-year-old monorecording which had me shaking my headin disbelief. I had already beensubdued into new levels ofrespect by other familiar tracks– dozens of them.
Juice Newton’s soaring‘Break It To Me Gently’ fromher Greatest Hits CD [CapitolCDP746489 2] exhibited evengreater power and clarity than
I had experienced through a thousandhearings. I sat there dumbfounded by
the sheer weight of Kodò’s Warabe[Sony SRCL4671], the dimensions of theperformance transcending the speakers
with such abandon that I was transported
to the live experience, while the weight
was overwhelming – as it should be.
Then I heard Lou Rawls sharing lines
with Dianne Reeves on At Last [Blue Note
CDP7 91937 2], a sound so authentic
and realistic as to shock, but that ancient,
ultimate test? I would soon realise thatI may never hear better in the time stillallotted to me. Morbid, perhaps, but true.

ABOVE: Inside one of two identical preampchassis. Volume adjustment uses relay-switchedresistor ladder [red, centre]. All-discrete circuit
has a FET input and differential bipolar output

On how many occasions and throughhow many systems have I heard The
Chordettes’ ‘Mr Sandman’? I never settledown for a session without the All-TimeGreats CD we gave away in 1994 [HFN/Ace Records, ACE 01]. I play the song
repeatedly, an invited ear-worm, but evenso, I was not expecting to discover subtle
details that had notbeen previously exposed.
Neither have I ever heard
mono so grandly wide anddeep that the thought of‘I wish it was in stereo’
never even crossed mymind. What this impressed
upon me in particular was
the measure of the Relentless amplifiers’
transparency, recalling those old clichés
about ‘lifting veils’.
Those little sounds I’d previously missed
forced me to reassess my already-highopinion of Cadence Records’ recording
capabilities in the 1950s – and it wasalready stratospheric. Remember: this ismono, for goodness’ sake, yet one could
separate the voices with as much ease asif they were arranged across the listening
space in a left-to-right array. And when
Cadence’s founder, Archie Bleyer, utteredthat deep-as-Isaac-Hayes ‘Yes?’ in the thirdverse, it hovered above the rest.

‘I was carriedback to a
recent live
performance’‘The inspiration for the Relentless
Preamplifier actually started with ourMomentum Phonostage’, confirmed
founder Dan D’Agostino during ourJanuary Zoom call. ‘The phono’s
front-end circuit used parallel FETs –we could add multiple pairs without
any increase in capacitance and thenegative bandwidth effects thatwould come with bipolars. The result
was a combination of extremely
low-noise with a striking dynamic
output’, claims Dan.
‘From there, I couldn’t resist
trying it in a preamplifier circuit. The
Momentum Preamplifier was the first
one to benefit from this FET input
stage, becoming the MomentumHD in the process [HFN Apr ’20].
However, I knew we could achieve
more starting with a blank slate andadditional real estate to fully exploit
the benefits of our FET concept.’
So will we see this FET circuit
exploited in other line stage
applications? ‘Certainly’, declares
Dan, ‘we’ve already inserted anadditional FET stage between theDAC output and the Relentless
Preamplifier circuitry in ourforthcoming Streaming Module’.
Dan’s outboard Phono Preamp(‘I haven’t had time to think ofanother name yet’, he admits)will be the next component in theRelentless series, powered off theback of the Preamplifier [see pic,p45]. RIAA equalisation will be allpassive, sandwiched between two‘Relentless’ FET stages and offeringa total +70dB gain. ‘It’ll be MC only’,
says Dan. ‘And more to come?’, I ask.
Dan pauses... ‘Yes’. PM

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

Lab
reportD’Agostino RELENTLEss PREAMPABOVE: All switching/phase invert and other logic controls are fed alongside PSU
rails through connectors in the top plate and front left foot of the centre unit. The
top (left channel) and bottom (right channel) preamps offer five balanced inputs, twoZone 1 and one Zone 2 balanced outputs. Remote is via Bluetooth control

It was growing perilously close
to a metaphysical experience,
though I am hardly a spiritual soul.
Having recently acquired the openreel tape which gave us BB King’s
peerless performance of ‘Don’t Get
Around Much Anymore’, which I wasgenerously allowed to include on
the same CD, I knew exactly how
amazing it sounds. Or so I thought.
I ended up kicking myself for nothaving the tape present at thelistening sessions because there
were details and a richness here I
hadn’t heard before.

MILLION DOLLAR MUSINGS
So, I had to contain my reel-to-reelbias and simply marvel at how good
the CD sounded, via the Relentless
Preamplifier and part of a systemcosting – literally – a million bucks,

ABOVE: Machined to match the preamp,
D’Agostino’s extravagant touchscreen
Bluetooth remote accesses volume,
mute, balance, input and absolute phaseor circa £800,000 in our money.
The transfer to the HFN/RR freebiewas better than I could haveimagined after 28 years: gloriouslywide, warm and as in-the-room as itgets. The stage width, the sense of
air – again, the music appeared tofloat, detached from the hardware
recreating it. And that is themagic. There is no other word for
performance this ethereal.
But I had one other regret as
I wallowed in BB King’s sublime
vocals: I wished the late Dave Wilson
could have heard not just whatson Daryl had created, but how hisfriend Dan’s Relentless amplification
managed to wrest more from theAlexx V than PM or I – or perhaps
even Daryl – could imagine.

As we saw with the D’Agostino HD Preamp [HFN Apr ’20], theRelentless Preamplifier’s watchface dial(s) indicate the available
preamp gain rather than absolute level. The ‘numbers’ andgain are different in this flagship model, however, with ‘99’
representing a default +5.4dB gain in our early sample (+8dB
is claimed), ‘76’ being unity (0dB) gain – below which theRelentless Preamplifier operates as an active attenuator. So, ‘64’
delivers –6dB gain (or x0.5) in this instance.
The two controls are synchronised, each rotary encoder
switching through a matrix of resistors [see picture, p43], but as
the top ‘bit’ was not enabled in this early sample there was noattenuation from ‘99’ down to ‘86’. The ±0.5dB steps kicked-infrom ‘85’ down to ‘26’ (31dB range), with coarser 1.1dB steps
to ‘12’ (14dB range) and 2dB steps down to ‘06’ (12dB range).
The steps from ‘05’ to ‘01’ (‘00’ is a relay-switched mute) are lesswell-defined but represent a range of ~9dB. D’Agostino informs
me that the 67dB volume range will be increased to ~75dB andthe 86.5dB A-wtd S/N ratio (re. 0dBV) boosted to ~95dB once
the anticipated full gain of the Preamplifier is realised.
More importantly, from a sonic viewpoint, the output
buffering is more rigidly enforced here, its 2.5ohm source
impedance much lower than that achieved by the HD Preamp[red traces, Graph 1] and its ruler-flat (±0.04dB/1Hz-100kHz)
response [black trace] unchanged across the entire volumerange. Distortion, too, is both very low and ‘flatter’ vs. frequency
at 0.0006-0.0014% (20Hz-20kHz) and 0.002%/40kHz while theHD Preamp offered 0.0003-0.0025% up to 0.011%/40kHz. Notethat the ‘right’ channel had marginally higher THD [Graph 2]. PM

ABOVE: Balanced line freq. resp. (black) and o/p imp.
(red) at 0dBV (Relentless, solid; HD Preamp, dashed)

HI-FI NEWS VERDICTWith the Relentless Preamplifier,
we are entering a parallel realm
with the likes of Bugatti’s Chiron
Super Sport 300+ hypercar – aworld previously unexplored andunattainable. The evidence is in
the sound as much as the physicalpresence of the preamplifier itself– true ‘audio jewellery’. Sonically?
Utter freedom from dynamic
compression, distortion, or evensoundstage boundaries. We are
truly stunned.

Sound Quality: 95%0-------- 100

ABOVE: Distortion versus extended frequency at 0dBV(Balanced in/out; left, black; right channel, red)

HI-FI NEWS SPECIFICATIONS
Maximum output (<1% THD, 47kohm)>24Vrms (Balanced)

Maximum input level (<1% THD)

>12Vrms (Balanced)

Output impedance (20Hz–20kHz)

2.4-2.8ohm (Balanced)

Freq. response (20Hz–20kHz/100kHz)+0.0dB to –0.01dB / –0.04dB

Input sensitivity (re. 0dBV)

542mV (Balanced)

A-wtd S/N ratio (re. 0dBV)

86.5dB

Distortion (20Hz-20kHz re. 0dBV)

0.0006–0.0014%

Power consumption

33W (32W standby)

Dimensions (WHD) / Weight (total)

432x349x432mm / 60kg

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