Integrated Amplifiers

Sleek design, comprehensive functionality and even a built-in wireless DAC make the AS-400 a thoroughly modern integrated amp – for today’s iTunes generation

Not long after the introduction of Micromega’s £2800 integrated amplifier, the IA-400, and its £1100 WM-10 wireless-equipped DAC comes a component that effectively combines the two: a new version of its integrated amplifier (with ‘AS’ instead of ‘IA’ nomenclature) featuring a built-in 802.11n Wi-Fi receiver/DAC, working to Apple’s latest AirStream protocols.
   As with any wireless connectivity – Bluetooth or Wi-Fi – there is something quite spooky about the ability for music stored on computer, mobile ’phone or PDA to be played through one’s hi-fi system as if by magic. Unlike open source DLNA/UPnP systems, however, AirStream (formerly called Airplay) is proprietary to Apple and works only with its iTunes media player, iPhones, iPads and the web-enabled iPod Touch. Uncompressed CD quality music can be streamed wirelessly and the technology is also capable of working with hi-res audio. In fact, the AS-400 claims to be all ready for receiving and rendering stereo music files up to 24-bit/192kHz. But don’t get too excited: Apple has yet to implement this facility in AirStream.

REAL WORLD ENTERPRISE
As Ken Kessler outlined in our review of the company’s top-of-the-line PA-20/PW-400 pre/power amplifier combo [HFN Dec ’09], the Paris-based Micromega company has been re-born in recent times, under new ownership and with fresh financial investment. Regarded a player in the Formula One division of compact disc replay in the early days of CD, producing high-end transports and DACs revered by audiophiles, Micromega eventually fell on hard times as the market became crowded and myriad high-end marques beat it at its own game. The new Micromega company remains what marketers would call an ‘added value’ brand. Its cheapest CD players and amps start around £900 a piece; however, its range-topping CD player is just £1600 and the aforementioned flagship pre/power combo is only £3300 – which in the world of audiophilia positions the marque in what might be termed the ‘budget audiophile’ category. It is classy, and it’s very much in the real world. Micromega’s 21st century products feature real-world functionality too.
   There are many thoughtful touches in this AS-400, all welcome on a modern integrated amp. While inputs names can’t be customised as they can on (generally more costly) modern AV receivers and higher-end ‘pure audio’ stereo amps, unused inputs can be disabled, so you don’t needlessly have to scroll through them when using the up/down keys. Covering pretty much all bases, yes, the AS-400 includes a phono input for vinyl lovers. It’s moving-magnet only (and one might argue that a customer buying an amp today that’s capable of streaming music wirelessly from an iTunes library is unlikely to own a vinyl collection and a turntable), nevertheless it’s a sensible inclusion that helps differentiate the AS-400 from the majority of integrated amps these days. The logic behind its inclusion, I wouldn’t mind betting, is that at nearly £4k it’s unlikely to purchased by a first-time hi-fi buyer, consequently it’s pitched as a modern upgrade for a music-lover’s system … and that potential customer might certainly have a wall of LPs, collected over the years.
   Also included is a proper old-fashioned tape loop, useful in the old days for ‘confidence monitoring’ when recording using three-head tape decks featuring separate record and playback heads, and still useful today for hooking outboard processors into the in/out loop. Additionally there’s a pair of RCA input sockets at the rear labelled Pro-In (‘Pro’ for Processor) that routes directly into the AS-400’s power amplifier section. You might want to use the AS-400 for driving the main stereo pair of speakers in a multi-channel system. Pressing the Mon/Pro button activates the tape loop. Hold the button in for a couple of seconds and the display switches from ‘Mon’ to ‘Pro On?’. Press the button again to confirm and the amp’s additional Pro-In sockets are activated..

MAJOR OMISSION
Furthermore I applaud the inclusion of a headphone on/off button on the front panel. Plugging a set of ’phones into the fascia’s 3.5mm mini-jack doesn’t immediately mute the signal to your speakers; the headphone output has first to be activated via the button switch. Only when activated do the speakers mute. It’s a pity Micromega didn’t also include the facility to leave the speakers on, too. The fascia also sports an additional 3.5mm input socket labelled ‘iPod’, but naturally this can be used with any external analogue source.
   At the rear is a DB9 connector for RS232 control and/or connection of Micromega’s iDok for iPods/iPhones, and subwoofer in/out sockets as well. Is there anything the designers and product planners at Micromega haven’t thought to include in the AS-400? Well, yes, there is one major feature not included. And its omission might be regarded as something of a catastrophe. What you can’t do is disable the on-board Wi-Fi receiver. Why is this disastrous news? See our Lab Report and you’ll see that the receiver invokes considerable hash into the Class D-powered amplifier.
   You might turn off your computer, shout up the stairs demanding your kids turn off their computers, and power down your home’s wireless router. But unless you live in the middle of nowhere, or build a Faraday cage for your living room, chances are the illuminated AirStream logo in the AS-400’s display window will remain determinedly blue – indicating the receiver is ‘ready to receive’ – as it detects your neighbours’ WLANs too within a 100m radius. In all the time I used it, the only occasion when I could hear the AS-400 au naturel was during the first couple of minutes of booting it up. What was I expected to do? Go knocking on neighbours’ doors? What a pity…

SUBTLE VEILING
Using Exact Audio Copy (EAC) I ripped several tracks from CDs to lossless WAV files for the listening tests that could be played either via iTunes from my Dell laptop (using HRT’s Music Streamer II USB DAC), wirelessly from my iPhone 4, and from an iPad loaded with music supplied by distributor Absolute Sounds for the purpose of the review. The iPad contained some hi-res files which did play seamlessly by the way, but were of course down-sampled by the iTunes/AirStream system.
   Directly comparing the sound from CD player against wireless streaming showed that the losses were in fact quite subtle. Indeed, the sound was bold and open with deep, taut and powerful bass together with smooth, easy-going high-frequencies. Anybody walking into the room would have been immensely impressed by the fact that the wall of wide-bandwidth sound they were experiencing was streaming wirelessly from my ’phone.
   But if I sat them down and made them listen critically to an A/B comparison between wired laptop/DAC and wireless iDevice, a subtle veiling of fidelity would be there for all to hear. While the sound appeared superficially similar, especially in terms of bass oomph and tonality (one of the reasons why many folk claim to perceive no audible difference between compressed and lossless audio, I suggest), the sound through the AirStream system took on a slightly grainy, harder character, together with a softening of leading edges of transients.
   Consequently, the image focus was slightly blurred, timbre and texture of instruments appeared less well-described and everything seemed, well, less real.
   A good example could be observed with a performance by the Omnibus Wind Ensemble of Frank Zappa’s ‘Dog Breath Variations’ (a chamber piece first released on the Mothers of Invention’s 1969 Uncle Meat album), recorded by Sweden’s specialist Opus 3 label [CD 19423]. This audiophile recording captures in exquisite fashion the sound of live instruments recorded in an enclosed space, and is from an analogue production dating from 1995, using a single-point Blumlein microphone set-up.
   Listening to the CD layer of this now rare and collectable hybrid SACD in my usual home system, the performers aren’t in my living room as such, rather I’m a through-the-keyhole observer of the live event – except in this instance, such is the scale and transparency of the recording and playback system, the keyhole is the size of my room’s far wall. In between and behind the speakers appears a further room, a room in which the Omnibus Wind Ensemble is performing.

THE JURY'S OUT…
The positioning of instruments in the room, their distances from the boundary walls of the recording venue, the sharp clatter of temple blocks and glockenspiel, the shimmering of vibraphone and ‘parps’ of the horns, clarinets and bassoon gives the sound a reach-in-and-touch quality: sonic holography from two channel audio replay demonstrated at its finest. That is, when listening through my resident Mark Levinson No.383 amplifier.
   Through the AS-400 the sound was less vivid, despite similar ‘weight’ and tonality. The three-dimensional image was spoiled, the instruments congealed into a block of sound with the space around them less palpable. Consequently, listening to the rip using my day-to-day laptop and USB-powered HRT Music Streamer II DAC, the sound delivered most of what could be heard directly from CD. Indeed if the sound from CD through the AS-400 was taken as a reference, that from the laptop could be judged as pretty much identical.
   And when streamed wirelessly from iDevice there was only the slightest hint of further veiling of transient dynamics and blurring of the already smeared image. So the jury must remain out over the ultimate transparency of the wireless technology in this instance, as Micromega’s implementation surely could be improved by throwing some money at the problem of in-board interference between the Wi-Fi receiver/DAC circuitry and the integrated’s high frequency switching amplifiers. Canning the receiver, shielding the Class D modules … anything might at least help ameliorate the deleterious effect of the hash flying around and about the AS-400’s chassis.
   Still, this is a meaty and highly flexible amplifier that can be judged pretty good value for what’s on offer. But only if you value the wireless facility, of course. And if you do, is it really worth the £1100 premium over the ‘wireless-less’ IA-400 amplifier?
   So ask yourself again: ‘Will I ever use it?’ Or perhaps you consider that for a visitor to be able to play music (or videos) from his/her pocket ‘iDevice’ – via the voodoo of wireless hook-up to your hi-fi system and TV – is a magical party trick that you can live without. After all, couldn’t you simply dock it?

VERDICT
This fully-featured integrated sounds like it’s a solid, powerful and smooth amplifier that’s been compromised by the inclusion of its Wi-Fi receiver. Hypex’s UcD Class D modules are renowned for their sonic capabilities, yet the sound of the AS-400 lacks sharp focus. The non-wireless IA-400 together with Micromega’s standalone WM-10 streamer might be a better option if you crave AirStream functionality.

Originally published in the May 2011 issue