Arcam FMJ SR250

Arcam SR250Remember the nineteen seventies – the golden age of the stereo receiver? From the nineties of course, the breed swelled to become multichannel, and these days it’s hard to find one that doesn’t have at least seven channels on hand. So it was with no small degree of curiosity that I came upon Arcam’s FMJ SR250, back in 2016. It’s a two-channel – 2.0 – design, purposed for stereo music listening, rather than AV.

Inside, it’s much of the FMJ A39 – a fine sounding Class G stereo amplifier – plus a decent DAC and a plethora of codecs for cinema use. There’s also 7 HDMI inputs and 3 HDMI outputs, which means that the product becomes the centrepiece of your AV system, as well as your hi-fi. No fiddling around with video cables is necessary when you wish to move from music to sound and vision. And uniquely for a two-channel product, it also contains a powerful room correction algorithm, one that is more effective and less invasive than any I have previously tried. It is sophisticated, so takes half an hour or so to set-up, but this done it works like a champ. Dirac Live works by getting the user to take a number of measurements and then upload these to a central computer at Dirac Research, which then does sophisticated calculations to compensate for the failings of your speakers, your room and indeed your listening position. It comes up with a new equalisation map that gives a flatter response and also corrects things in the time domain.

Like the old two-channel receivers we used to buy in the nineteen seventies, the SR250 has an amplifier and an FM/DAB radio tuner in the same 433x425x171mm, 15.1kg  box. To this you can add a Cirrus Logic CS42528 DAC chip, and an analogue control section based loosely on the high end C49 preamplifier – complete with its special distortion nulling technique and multiple power supplies to negate inter circuit block noise. (Arcam says that the video stages have no influence on the audio section, by the way.) There’s a resistor ladder volume control, which is claimed to add no distortion.

A large toroidal transformer helps the power amp section punch out a claimed 90W RMS per channel, and this doesn’t seem unrealistic judging by my listening tests. It’s notable for running in Class G which means it has two power envelopes. The first is as a Class A with no crossover distortion, but when called upon to deliver over 23 watts, it goes into Class AB to really raise the roof. This system isn’t unique to Arcam; we’ve seen variations on it from other manufacturers over the years, but certainly the Cambridge company has developed it more than anyone else I’m aware of, recently.

The SR250 can run as a ‘straight through’ stereo amplifier, with no processing, from a line level analogue input, or you can use its onboard DAC and/or home cinema codecs should you wish. You can use it as a preamplifier, or bi-amp it, or hook it up to the massive P49 power amp should you wish. In other words, it’s a versatile beastie and everything is configured easily in its set-up menu which is best navigated via your TV. The unit gives access to internet radio stations via the network connection (also needed for Dirac Live setup), which also interfaces to UPnP audio servers. The rear USB port supports memory devices. There’s a free MusicLife iOS UPnP and control app downloadable from Arcam’s website, and a bundled system remote control. Other features include a power port for Arcam rSeries accessories.

The Dirac Live system deserves an article in its own right, as it’s so powerful and comprehensive. But when the SR250 is connected up to internet, and to a Mac or PC, you can do a basic configuration in around fifteen minutes. It’s a case of plugging a microphone into the computer then moving it around the room (the software tells you where to place it), then the system does a series of frequency sweeps. This done, the data is sent off to Dirac headquarters, where the numbers are crunched by supercomputers, and the system then sends back a frequency- and time domain-corrected ‘map’ for the SR250. You can then run this in either corrected or uncorrected mode, and hear the difference. In my room, the ‘before and after’ frequency and impulse plots correctly identified a number of issues that I’ve long been aware of, and a couple that I wasn’t.

Running in direct mode with no Dirac processing, the SR250 proves to be a very clean, crisp and open sounding device indeed. Don’t think that means ‘sterile’ though, because the great thing about this receiver – and the amp that it’s descended from – is that they combine a wonderful sense of openness and detail with a natural musicality that makes listening a very involving experience. To me, this is what makes this generation of Arcam amps truly great, and it’s something that in all honesty I couldn’t say of the products they were making five years ago.

For example, hook a high quality analogue source up to the SR250 via the line inputs, and you’ll be amazed by the scale, power and get-up-and-go. At the same time though, it has an unexpected transparency that makes most solid-state amps sound mushy and polluted. You don’t quite get the blindingly transparent sound of the full Class A Sugden A21a for example, the SR250 is just a bit softer and more opaque, but you still get a strong taste of Class A. There’s an inherent smoothness and incision that’s hard not to live with when you go back to a Class AB or Class D design. Importantly though, don’t think this some soft, fat old smoothie in the style of a budget valve amp – it isn’t. It’s a well-lit and quite forensic sound that doesn’t have any excess warmth. It’s not the sort of thing to buy to sweeten up an otherwise cold sounding system – think NAD for that.

Via its own digital inputs, driven from a TEAC CD transport, the SR250 sounds excellent. It is punchy, crisp and tight – with just a slight lack of depth perspective and fine detail reminding you that this isn’t a high end digital converter. The DAC onboard the Arcam is certainly the match of most £500 designs, and that means system buyers can save this amount and spend it on better speakers. Running via coaxial in, it made a very nice noise with Coldplay’s X&Y, giving a large, powerful confident presentation that lacked depth perspective but more than made up with a wonderful wide soundstage, a tuneful and powerful bass and a sweet and smooth treble. This Arcam really is something of a muscle amp, considering its price.

With Dirac Live switched in, there was a profound change to the sound. I’ve heard many room correction systems and normally you’re sat there listening to the sound of heavy, ham-fisted DSP that solves some problems and introduces others. Not here though; regardless of source it worked a treat. Despite cutting out the obvious bass boom in my room, it gave subjectively more upper bass, pushed the top end up slightly and cut out an upper midrange peak. The system sounded much smoother, but interestingly it was snappier and more musical too when playing Gregory Isaacs’ Night Nurse. Bass was more tuneful and there was a more positive central image. Despite this, there was no heavy breathing from the Dirac system, and on balance it was better in than out. If I lived in a room with ideal acoustics and was able to position my speakers perfectly, I think it would be better out – but it’s a remarkably effective sticking plaster for imperfect acoustics.

Arcam’s FMJ SR250 is an interesting product, unlike anything else around. It’s a serious solution for stereophiles who love watching movies too, and don’t want to drown in a sea of cables. It’s also brilliant for those with rooms with highly imperfect acoustics, as it’s able to tune your speakers to your room in a far more powerful way than the usual expedient of introducing more soft furnishings or fiddling with your cables. Dirac on or off, it sounds superb for its price and has a welter of handy facilities, from decent sounding DAB radio to a fine built-in DAC. Heartily recommended.

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