Stereo power amplifier, Rated at 200w8ohmMade by: DlAgostino LLC, Connecticut, USA

POWERAMPLIFIER

DAgostino MomentumStere o ([zs,soo)

One year on from HFIV's exclusive review of D'Agostino's astonishing Momentummonoblock amplifier comes this stereo version with its dual-metered 'watchface'Review: Ken Kessler Lab: Paul Miller

.[ n rf*:Jil":ff,H:n"''V V ::ru;':1,1"":il:ft,?il:J,

acquisition, one of its greatest joys

is opening the box, lt should be an'Experience', with a capital 'E'. DanD Agostino 'gets' this, because even thecontainer for his Momentum Stereo PowerAmplifier is, well, downright cool: it's awheeled, family suitcase-sized Pelicancase, the same transit enclosure used byfilm crews to keep their cameras safe fromairport luggage handlers.

We've been here before, last luly to beprecise, when we had the honour of theexclusive world scoop for the monoblocks,a review that anticipated its worldwidesuccess. This time I learned that the initialthrill is repeatable: the precious cargoarrives cosseted in its shaped foam insert,complete with cut-outs for easy access bytwo pairs of hands. And you will need a

friend to help you with the circa 40kg load.You'll want to get this up-and-running as

soon as possible, without back injury.What counters the overwhelming sense

of dd./? vu are three things. First is that onlyone unit has been delivered, telling youthat, secondly, this is a stereo amplitier. Thetwo sets of speaker binding posts on theback, the two XLR inputs and - at the front- a meter measuring the behaviour of twochannels inform you that this may looklike a Momentum, but it's two-in-one.The third? The review sample affived inthe new black finish, and it is nothingshort of alluring.

Aesthetics first, then. I've now seenblack DAgostinos on three separateoccasions, and every time, I have been

RIGH'I: Ro/vs of stepped venturis ale drilledinto the marsive solid<opp€r side se<tions,

cooling eight pai6 of Sanken polrrer transistorsper channel. The main pourertranstormer liesunderneath the smallertoroid seen here

reminded of Dan's appreciation forwristwatch visuals. They inspired theoriginal Momentum's dial, and the samestylistic conceit has been adapted toprovide the metering for both channels inone dial.

REIR,OGRADE MOTIONBy following two vertical arcs, the needlesreplicate the activity of what are known inwatch circles as'retrograde hands'. Thesefly from zero to maximum and back, unlikeconventional hands that complete a fullcircle. As all mechanical meters used forelectronics complete an arc rather thana circle, this hi-fi/horology connection is

natural, not forced. What's even more aptis that the exposed 'hub'for the metereven looks like a watch's balance.

While a silver version would have oozedfamiliarity, the black finish rewrites therules: it simply looks better - to my eyesat least - than the silver colour, and thecopper heatsinks and venturis running the

length of the chassis complement the blackin precisely the same manner that a rosegold watch with a black dial is a standoutamong timepieces. An added visualtreat is

the copper visible through the slots in thetop of the case. With all due respect to ouramazing photographers, printed imagesdon't quite do it justice.

Those venturis dealwith the heat fromthe banks of output devices, but the unitnever got as hot as the monoblocks. On atransatlantic call, Dan explained that thestereo uses'... exactly the same circuit as

the monoblock. The only difference is thatit employs fewer output devices, reducingthe output from 300qch to 200wch.'

That's straight from Dan's mouth,and it explains why switching to thestereo version brought us d6ji vu: theysound so close that the differences forother manulacturers would be equaltoacceptable sample-to-sample variationamong two of the same units poppingconsecutively off the assembly line.

20 | www.hif inews.co.uk I AUGUST 2ol2

Which made it both easy and tough toassess:'easy' because I vividly recall themonos, but tough because they're almosttoo similar. Warily, then, I slipped it intothe system using a variety of preamps

- this only accepts balanced signals viaXLRS - including the Mclntosh C2200 andC22 Commemorative, fed by the MusicalFidelity kW25 transport/DAC and drivingWilson Sophia 3s. Allwires were YTER.

There was nothinqto address otherthan setting themeters to their highersensitivity, becauseotherwise lwouldn'thave known the amp

'It's a Clydesdale

had been on for three hours - not out ofsome form of journalistic hyper"integrity,but simply because I had other things to do

- thus my first impression of the amplifierwas in its warmed-up, burned-in state.

@ rar,renln TREsENcEA day later, switching on from coldrevealed it to need mere minutes to

deliver nearly all of itsperformance, with fewsonic gains to be madeafter the first hall-hour.Hence, you don't have

to provide a day'swarning before comingin for a demo. As lheBest Of Elvin Bishop

AEOVE: Dan's inspired-by{atchG vision

continues: the StelEo, needing two needlesmirrors lvhat horologists call 'rctrcgrade' hands

- travelling in an arq not a circle

Sophia 3s, making those woofers shake

their respective bootjes in the most soulful,lusciously languid, almost salacious way,without ever sounding sloppy.

'struttin' My Stuff is the best example ofthis, with snappy bass, keyboards that have

a harmonium's tinkle and crisp drumbeats.The Stereo separates the instrumentsinto layers in front oJ the listener, as ifto augment the left/right placement.It's almost'enhanced 3D', but iL serves

to showcase every instrument. Lovers

of vocals would delight in the interplaybetween the near-falsetto of MickeyThomas and Elvin Bishop's growlier delivery,the amplifjer balancing utterly disparatetextures with the deftness ol a Rothko.

Where the Stereo most recalled its splitsibling is in its ability to convey majesty -of prime importance in rock as much as

in orchestral. One minute and 57s into'Fooled Around And Fell ln Love', settingup the music for the positively stately leadbreak, is a drum fill across the soundstagewith the sheer grandeur of a Kodo drumphrase. Here the Stereo behaved with suchunassailable command that lkept asking

myself, 'Who needs more?'Weight, power,palpable presence - the Stereo is theClydesdale that makes other amps seem

like Shetland ponie5.Then the soaring guitar work shows

you how the Stereo can climb thosefrequencies, the attack so precise and theascent so smooth that you forget you'relistening to a cD. Bishop rips his heart o

that makes otheramps seem likeShetland ponies'

was working: they barely moved, evenwhen the levels approached the silly. Thisamplifier dispatches the 50phias with ease.

ln my situation, I can't imagine needingmore power.

Switch-on is via a soft-touch controlbeneath the front edge ofthe unit, belowthe meter. ldidn't even listen to it until it

was in my player, lcouldn't have chosen a

better'reveal', should poker terminoloqyhave any part in hi-fi assessment, of theMomentum Stereo's personality. This discis heavily balanced toward funk elements,the sort of thing that makes PRAT ('pace,rhythm and timing') addicts swoon. TheStereo dug deep into the bowels of the

Dan D Aqostino is surprisingly forthcoming about his Plans for the future, withonly one hint of intrigue. Although he had said he would stick with analogue,Dan has since told us, 't have been 'reconsidering" the design of DAcs.' lt'sa statement pregnant with possibilities, though this is clearly not as mucha priority as the arrival ol three products to complete a basic D'Agostinoamplification line-up. Already announced, though absolutely no timetable has

been proftered, in order to predlude self-imposed deadlines and any possible

disappointment caused by missing arbitrary ones, are a preamplifier' a phonostage (or amplifierl and an integrated amplilier. I susPect that is probablythe order in which they will appear. What Dan couldn't resist saying, betoreterminating our call, is that, he 'may have a big surprise lor us by the year's end.'

AUcusT20l2 | wwwhifinews.co.uk | 21

ABOVE: Balanced (XLR) inputs and screwdown speakerterminals' The close rttingof the latter and surounding metal casework means gEat care should be taken with

bare speaker cable and/or4mm spade adapte6

D'AGOSIINO STEREO (r 2 3. 5 o o)

unsurp singly, perhaps, the'Stereo behaves exactly like a

smaller sibling to the monoblock Momentum [HFN July'11]Rated at 2X2OOWto the mono's 300W the Stereo features a

sim i'arly well'reg ulated power suPply and delivels far closer to2x24OW8ohmwith 2x3gOW4ohm Underdvnamic conditions

there\ an appreciable uplift, its transient powet improving to3OOW 55OW 97OW and l.3kW into 8, 4, 2 and lohm loads'

respectively [see CraPh 1, below]. So whilethe Stereo la€ks thefullbeefofthe parent monoblock, it3 no slouch and willsurely

tackle the most demanding loudspeakers with telative ease.

Likethe Momentum. the Stereo also incuts a modetate butvery consistent levelof distortion of -0.1% from IWto 200W

and across a verywide 5Hzto 40kHzfrequency bandwidth

hee Craph 2, belowl. Distortion increaees with decteasing

ioad rmpedancp lctaph I] bul. once again. the rrend 6 largelv

unvaryinq right up untilthe point of clipping. Alonq with itsprodiqious power output, this uniformity'is keytothe Stereo\

sound quality. And, despitethe amplifiels modetate 0 3ohm

output impedance it ako maintains a veryflat (-0.ldB/2okHz)

response without further loss into the lowest impedance loads

-just like the Momentum monos.The Stereo is slightly quietef than the monoblocks we

tested lastyeat, the fotmer offeting a wide 90dB Awtd S/N

ratio (re. Odg). Performance is about 5dB pooreron the l€ftchannelhere, possibly due tothe proximity ofthe mains

inlet, butthis will not be audible. Readets are invited toview a comprehensive QC Suite test teportfor DAgostino\l\romentum steteo amplifiet by nauigatinglo www.hifinewsco.uk and clicking on the red download button PM

t

out on this one, and the D Agostinolets you know it. lwondered if thesupplied gloves were for moPPingsweat off the Performer's brow.

As a laugh - and because I love

the song to pieces - lled it'TheDoor ls Still Open' by The Cardinals.

For the first time, I noticed howcrisp is the snare positioned behindthe vocalists on the mono doo-woP

masterpiece. The Stereo Provideda rich woodiness to the Piano,the sax had that moist reedinessthat suggests real rather thanrecorded. lt sounded so much like

the l\,4omentum monoblock that onehas to accept Dan's statement thatit is, for all intents and purposes' thesame beast.

From the vocal histrionics of thattrack - we're talking .lohnny Ray-type

melodrama - to'lohnnY Ace ls Dead'

on Dave Alvin's recent masterpiece'Eleven Eleven, meant onlY a change

ol bombast from acoustic to electric.There's a lot going on, with thatkind oI trashy drumming lound onlY

in country & Western ensemblesor juke joints, and vicious electricguitar that recalls Alvin's work withThe Blasters. The Stereo Proved as

adept with this boozy swamP rock as

with the delicacy of doo-woP.

AI,L-ROI'ND COHERENCEPresenting the sound as a wave (as

in a surfeit of water such as surferspray lo4, the Stereo exhibits wall'to-wall and lloor-to-ceiling cohesion.Within that panorama, You canpick out every sound, and locus on

it to your ears' content. This is an

amplifier for the fastidious, but whoalso need (or simply crave) dynamicslam to temper the subtlety. ltcould, indeed, be all things to all

men/women. And that's why I dugout something equallY'huge' butdemanding absolute finesse.

Etta James' breathtaking coverof The Eaqles' 'Take lt To The Limit'graces that song with a gosPel

backinq qroup, blues guitar, a grandpiano in every sense of the word. ltqrows and swells to relentlessness,

and the Stereo grows with it,the lower registers and drum fjllsreminiscent of the Elvin BishoP

track, subsumed bY a huge chorus,Etta's voice front and centre. For any

amp to do justice to her PiPes, it'sgotta have both power and clarityin abundance. The Stereo couldhave been made for her. As fortheTemptations' 'The WaY You Do The

Things You Do', well- lain't never

heard the brass sound so shinY. ltcould be this amp's anthem.

Thanks to a number of causes, I'min a 'perfect storm' of financial woe'which is a good thing: once the unitwas collected. I didn't immediatelystart pining, dreaming of a Lotto

win. Yet I would gladly live with theIVlomentum Stereo without lettingmy mind stray elsewhere And I

admit, in the most infantile mannerpossible, that the looks grabbedme almost as much as the sound,however heretical that maY seem.

It is an astounding performerthat also happens to be as as

'wantable'as any lcan recall, one

that joins assorted Nagras, WAVACS

and Air Tights on mY'bucket list'.But - given how this Proves howtheMomentum monos are no fluke - I

still wish that the D Agostino amPs

were called'1st Dan','2nd Dan','3rd Dan'and so on, because, man,

do they kick ass. O

At just over the price of onemono unit, the Stereo will Proveto be a godsend for those whocan't afford the Pair. lt seemsabsurd to callthis'a bargain',but in some systems, it may even

be preferable to the monos.combine sublime sound, a senseof unlimited power on taP andlooks that beggar the term 'heart-stopping', and you have the mostexciting and desirable solid-stateamplifier on the Planet.

Sound 0uatity: 89'/o

n " 1 ' ',. :il,- .. t;;';rrr,li.L no

oynamrc Pos'r odpnr >> E

ABOVE: Dynamic power output versus distortion into

Sohm (btack trace),4ohm (red), 2ohm (blue) and

lohm (green) speaker loads. Excellent load tolerance

Fr'q!'ncy >> @

ABOVE: Distortion versus extended lrequency from

5Hz'4okHz at lOWSohm {black, left; red' right)

l!

e

E

Power output (<1sTllD. 8/4ohm)

3O0W/550W/970W/l.3kW

A-wtd s/il ratio te.0dBW/200w)

AUGUST2ol2 | www.hifinews.co.uk | 23