Musical Fidelity AMS 35i

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Musical Fidelity AMS 35i
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From Hi-Fi World - December 2009 issue


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Hotter Than July



Brand new from Musical Fidelity is the gargantuan “pure Class A” AMS35i integrated amplifier. David Price warms to it...


Talk to Antony Michaelson about his prodigious product portfolio and there are a few select designs about which he speaks with particular affection, the A1000 being one of them. This was one of the first British battleship integrateds. Of course, Japanese marques like Sansui once specialised in the breed - producing massive, usually heavily Class A, powerhouses with lavish looks and a fine feel - but here in the UK it wasn't until the advent of the A1000 in the early nineties that super integrateds ever existed.


Michaelson’s monolith was a lavish affair, being a two-box design, the first being the amp itself and the second the power supply (11kg and 7kg respectively). It boasted 50W RMS in pure Class A from two sets of eight heavily heatsinked transistors, aspirated by two chunky toroidal transformers in the other box. Switch it on and within an hour most of the casework was too hot to handle despite all that elaborate heatsinking, such was its prodigious power consumption...


On delivering this, the new AMS35i to me, Antony declared it to be the A1000’s spiritual successor, and you can see why. It’s pure Class A into 8 Ohms. He argues that many manufacturers assert their products to be ‘pure Class A’ amplifiers, but are actually simply Class AB amps biased just a bit more towards Class A. This is emphatically not the case with the ‘35i, he says, and the temperature rise of the massive heatsinks (about 35C) is testimony to this. Suffice to say, after my review sample had been on for an hour, the central heating went off and I was contemplating making myself some cheese on toast right there in my listening room...


Boasting 35W RMS per channel into 8 Ohms [see MEASURED PERFORMANCE], the AMS35i is a dual mono amplifier, each ‘bank’ with its own separate transformer. The preamp also has separate power supplies with discrete windings on the transformer. The circuitry itself is said to be “a direct descendant of the Titan and AMS50 circuit designs and is very closely related to them”.


I have to say that this is one of the most attractive modern Musical Fidelity products I’ve seen for a while, looking purposeful and imposing (it’s not small at 483x148x475mm and 28.3kg), yet subtle and classy too - especially in the black satin finish of our review sample. Whilst it lacks the silky perfection of Japanese esoterica, it’s certainly very well made and finished. The front panel is machined from solid, milspec aluminium billet, with an exclusive titanium G2 finish, in silver or black. The badge is made from medical grade stainless steel. The top and back are machined from solid and the heatsinks are custom made for maximum efficiency.



The front panel layout consists of a large, smooth operating central volume control, with smaller source selector buttons with individual blue LEDs. Round the back there are four RCA phono inputs (including a tape loop) and one balanced XLR, and one fixed (tape out) and one variable (pre out) RCA phono outputs, plus two pairs of 4mm speaker binding post outputs. The AMS35i remote is “one of the single most expensive components” of the package. Exquisitely machined from solid, it’s a handy thing to have in your dressing gown pocket should a midnight burglar decide he has as much right to own your hi-fi as you.


As with everyone here at Hi-Fi World, I am an ardent fan of valve amplifiers, but I personally must confess that I don’t listen to them very much at the moment. My World Audio Design K5881 (heavily modded) is one of the most divine performers when in its comfort zone, but as valve aficionados will know, this is easier said than done. My own listening room is quite large and my choice of reference loudspeakers is demanding on any amplifier; while my NS1000Ms have a quoted 91dB sensitivity they’re a stiff load and reduce many transistor amplifiers to nervous wrecks. Hitting the loud pedal with the K5881 driving the Yams simply causes the poor old valve amp’s (admittedly very tough) transformers to saturate, and suddenly my hi-fi is doing a passable impersonation of a small motorboat chugging in to Portishead marina...


When the K5881 is in its comfort zone, it displays those splendiferous virtues of any fine tubular belle. It is tonally smooth, spatially accurate and rhythmically eerily natural; music just flows forth like the words of your mother-in-law who won’t stop talking. For this reason, and in the absence of any comprehensively bigger and better tube amplifiers, I found myself investigating Class A transistor amplifiers, and these have now become my preferred tool for listening in my own room.

The key drawback of Class A is the amps get hot, because they run in such a way that the output transistors are permanently switched on (whereas in Class AB of course they switch on and off at higher outputs). The key benefit is the lack of switching distortion, which invests the humble transistor amplifier with a profoundly different quality to what people are used to. Music is suddenly clear, almost icily so, like a frozen sea under blistering blue sky. All the grey ‘fug’ that the switching distortion of Class AB disappears at a stroke, and it’s like the sun has come out.


Still, just being Class A isn’t a guarantee of perfection. I very much like the £3,500 Sugden IA4 for what it does to the music - which is to make it very clean and fun - but there’s certainly a bright upper midband there to be heard, especially through speakers such as mine which, like most metal drivered speakers, aren’t backward in coming forward. It’s a great amp, the Sugden, but not perfect. Fascinating then to get the chance to try the Musical Fidelity AMS35i, which at £6,000 is surely the most expensive example of the integrated breed I’ve heard, and without doubt the most purposeful...


After about an hour’s warm up (the amp, my room and then me - in that order), my first instinct was to reach for the nearest LP. Duly, Wings’ ‘London Town’ (“ah, Wings, the band the Beatles could have been”, to quote Alan Partridge!) was cued up, and I sat back. As Musical Fidelity amplifiers go, this was one of the sweetest and most beguiling I’ve heard. Their kW stuff sounds impressive in my system, but the AMS35i sounded beautiful. There’s a smoothness, delicacy and warmth to this amplifier that I haven’t heard outside of a valve amplifier, and it was so pronounced that I’m still trying to fathom it weeks after first setting ears upon it.


‘London Town’ is a typical late seventies analogue recording (done mostly at Abbey Road Studios, of course). It has a richness and a sheen that’s simply not possible to hear anywhere now. I’m not sure if it was McCartney's (and Denny Laine)’s choice of exotic cigarettes, but the song lilts along with an unusually relaxed gait, and practically every transistor amplifier fails to catch this lackadaisical feel. Not so the AMS35i, which opened up the song and let the listener in. The slightly shambling, pedestrian rhythm with its various stop-starts wasn’t forced or muddled. Instead the Musical Fidelity remained in confident control, happy to amble when the song demanded, then ready to rock when the song's energetic, Hammond organ-driven bridge came to be.


Impressed as I was with the AMS35i’s unforced musicality, this amplifier’s tonality really made its mark. The brass section that permeates the song was rendered with unexpected accuracy, the strings had a supernaturally silken sheen and McCartney’s vocals were carried with an almost disconcerting realism, overdubs and all. Tonally this amplifier is a smoothie alright, but only in the sense that it doesn’t add grain or grit.


Warping forward twelve years, and The Orb’s ‘Little Fluffy Clouds’, a classic slice of ambient house from 1990, was next on the turntable. With a heavy sequenced sampled drum loop driving the song, it represents a distinct upping of the pace compared to the Wings track, and immediately the AMS35i snapped into life. The amplifier was able to ‘pick up its skirt and run’, so to speak, showing its natural speed to great effect. Even at high volume, with the Yamahas’ twelve inch cones flapping like flares in seventies Coca Cola advert, the big Musical Fidelity served up large dollops of clean power, stopping and starting like its very life depended on it. Despite all its low frequency travails, the Rickie Lee Jones sample was rendered with cut-glass clarity, and the sampled keyboard loops chimed cleanly and purposefully out of the mix. Despite its low rated power, this is as confident a 35W as I’ve heard, with prodigious amounts of low frequencies served up. Compared to my reference Sugden, there seemed to be a whole extra octave of bass!


Time for a wilfully unpleasant recording, then. XTC’s ‘Skylarking’ is a great baroque pop album from 1986, but ambitious as it was, Todd Rundgren’s production was typically low rent mid-eighties,  sounding bright and brash with just a few too many clangy early digital keyboard sounds for my tastes. ‘The Meeting Place’ is quintessential XTC fare, Colin Moulding’s vocals counterpointed by chiming DX7s in a lovely melodic way, but it’s hard work on most high end hi-fi systems. Not so on the AMS35i, which seemed to cut through the top layer of grit like an expensive car polish, letting the recording’s true colour shine through. Although not exactly warm, this big integrated simply refused to ‘take the bait’ and go grainy, whereas I’m sorry to say that the (admittedly a lot cheaper) Sugden duly ran with it. This amp was able to unlock the recording, getting me closer to the song and its performer. Impressed as I was by its svelte tonality, all along the Musical Fidelity carried the song’s rhythm with remarkable subtlety. On this track the drummer shows a certain Ringo Starr sensibility when bashing his snare and hi hat, but his ability to float around the beat in a Beatles style has rarely been as apparent as through the AMS35i.


Moving to a great slice of modern jazz funk with sky-high production values and masterful recording quality, and The Crusaders’ ‘Street Life’ (Japanese pressing) was duly cued up. Here the big Musical Fidelity flew, showing its ability to drive my speakers with complete confidence. The system conjured up a wonderfully expansive recorded acoustic; the speakers disappeared and the listener took on a front row seat. The low level detail was breathtaking; I was amazed to hear maracas I’d never previously heard (despite listening to this song regularly since 1979!), and I loved the way it was suddenly so obvious that the drummer was playing the hi hats way off the beat. Singer Randy Crawford’s voice was about as rich as I’ve ever heard it via recorded music, and her phrasing was exceptionally well carried. Even though this amp isn’t dynamic in a shouty, showy way, it was better able to carry the emotion of a musical crescendo than any other integrated I’ve heard. It doesn’t ‘turbocharge’ attack transients, making them artificially pronounced, like some transistor amps I’ve heard, yet is nevertheless blisteringly fast and expressive.


Have moaned tediously for many years about never quite finding the right amplifier to match my annoying pernickety speakers, I suddenly find myself listening to it. To be brutally frank, this is quite a strange amplifier, taken by the standards of the rest of the market. It is exceptionally clear and clean, yet errs on the sweet and velvety side (whereas the Sugden Class A amps fall the other side of the middle marker). It has blistering perceived power given its rated power output, and a strangely capacious bass that underlines the music just in the right way, yet it’s never overblown or ponderous and doesn't slow things down. Treble is silkier than a Chinese cheongsam and yet the midband is clear enough to communicate every last nuance of the recording, right at the back of the room.


Given my obvious enthusiasm for the Musical Fidelity AMS35i then, I feel I should find some criticism by way of balance, but it’s not easy. I suppose you could say it’s not quite as lavishly finished as some of the most expensive Japanese integrateds, but I’m afraid that’s the best I can do by way of retort. So if you’re looking for an exceptionally beguiling, wonderfully open integrated with just enough power for a large room, this is bound to warm the cockles of your heart.



Marantz TT1000/SME V/Lyra Titan i turntable

ANT Audio Kora 3T Ltd. phono stage

Sugden IA4 integrated amplifier

MF Audio Passive Magnetic Preamplifier (silver)

NuForce Reference 9SE monoblock power amplifiers

World Audio Design K5881 (modded) power amplifier

Yamaha NS1000M loudspeakers

verdict five globes

Blissfully sweet yet open sounding integrated with superlative rhythms and eye-watering detail.


Musical Fidelity

+44(0)20 8900 2866


- natural musicality

- cavernous soundstaging

- silken tonality

- breathtaking detail

- remote control


- price



In spite of its massive size and weight the AMS35i produces just 32 Watts into 8 Ohms, so it will need reasonably sensitive loudspeakers, However, nowadays, large floorstanders are relatively sensitive, offering 89dB or so from 1 Watt (nominal, 2.8V) and working into a 4 Ohm load the AMS35i perfectly doubles its power to 64 Watts. In real life then, with nominally 6 Ohm loudspeakers that usually sink to 4 Ohms at low frequencies the AMS35i will go loud enough for most people.


Distortion was all but negligible at low output powers, even at 10kHz into 4 Ohms, a test that usually provokes some distortion. Only at high power into 4 Ohms at 10kHz did distortion rise a little to 0.015%, still a negligible amount. So the AMS35i offers very clean reproduction. A damping factor of 44 suggests reasonable but not overly large amounts of feedback are used.


Input sensitivity was very high at 120mV via unbalanced phono socket inputs and balanced XLR inputs, so low volume control settings will give high volume from the loudspeakers. Noise was 3dB higher from the balanced line inputs, measuring -80dB, than the unbalanced inputs at -83dB, likely due to internal balanced receiver chips. Balanced inputs can cancel cable noise however and usually give good sonic results.


The AMS35i measured very well in all respects. It is best used with low impedance loudspeakers to maximise its output potential, then a healthy Class A 60 Watts should give great results. NK

Power 32 Watts


Frequency response 4Hz-55kHz

Separation 110dB

Noise -83dB

Distortion 0.0045%

Sensitivity 120mV





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