The audio amplifier is in transition, because it’s becoming hard to justify a physically large, heavy, and energy hungry design today. Although Class D operation offers a resolution to all these issues, audiophiles often dismiss this technology for its sound quality. Which is why the Cyrus Audio 200 power amplifier is potentially so important.
With the Cyrus 200, Cyrus Audio claims to have built a Class D circuit that delivers high power (200W into six ohms, 175W into eight ohms) that not only fits into the standard Cyrus half-width HA7 die-cast aluminium chassis, but also sounds exceptionally good. Cyrus has eschewed buying off-the-shelf amp modules (from companies like Hypex or ICEpower), and instead designed its own Class D amp modules from first principles.
Significantly, the company recognised that Class D’s ‘voice’ is effectively governed by the impedance of the loudspeaker to which the amp is connected. Starting with the all-in-one Lyric system, Cyrus included its SID (Speaker Impedance Detection) circuit in all its Class D designs. On power up, SID sends a reference signal to the left loudspeaker, compares what it receives from the loudspeaker with that reference, and adjusts the output of the amplifier accordingly. In most other Class D systems, the best you can do is to cycle the power a few times and hope for the best.
Cyrus Audio calls the Stereo 200 a ‘hybrid’ design, but it’s not a hybrid in the conventional audiophile sense – don’t go looking for valves. Instead, the company chose to couple this sophisticated Class D design with a linear power supply more commonly found in Class A and Class AB amplifiers. Class D designs are so commonly accompanied by switch-mode power supplies that people mistakenly think switch-mode is an intrinsic part of the design itself. And when you gaze long into the ‘singing shoebox’ case, the small 475VA toroidal transformer will gaze back at you (no abysses were harmed in the making of this sentence).
By using this ‘hybrid’ Class D, the Stereo 200 sports a smaller and lighter transformer than expected for a 200W power amplifier, and the whole device weighs just under 7kg, or a shade below fifteen and a quarter pounds. Staying with imperial measurements, Cyrus has long been good at squeezing a quart into a pint pot, as is reflected in the densely packed back panel of the Stereo 200. It has XLR and single-ended phono inputs, a pair of ‘chain’ phono outputs for additional power amplifiers in a bi-amp setting, a mini-jack standard trigger socket, and two Cyrus’ own MC-BUS phono connectors, which are used to send comms signals between Cyrus devices. Add in two pairs of WBT-like loudspeaker terminals and a three-pin ICE socket, and there is barely any rear panel real-estate left – just enough for ‘made in England’, in fact.
While this is not Cyrus’ first stab at Class D (that honour goes to Lyric), this is the first time the company has incorporated the technology in its main audio separates line. The intervening years between the launch of Lyric and the Stereo 200 has allowed Cyrus to refine the technology, with higher quality components in the reconstruction filter, and greater isolation between ‘support’ electronics and the amplifier itself.
We used the Cyrus 200 with the Stream XP2 Qx streaming preamplifier/DAC, fed from a Naim UnitiServe. The Stream XP2 Qx is an upgradable 24/192 DAC with UPnP and DNLA compatibility through Ethernet. However, this meant single-ended output only. This is an excellent streamer, great DAC, and a pretty good preamp in its own right, especially at around £1,600. The Stream XP2 Qx’s first round of reviews were good, but they criticised its reliance on the remote handset; since then, Cyrus announced its own Cadence app, and this moves the functionality of the design forward a few notches.
Back to the Class D design. The Lyric this amp is designed from always had ‘space’ and, in terms of soundstaging, some ‘pace’ too; but the Cyrus 200 adds more ‘grace’ and even more ‘pace’ to the mix. What this means is that we can put away the ‘Class D’ discussions, while talking about how the amplifier actually sounds. If anything, the way the Cyrus 200 sounds in the flesh is closer to a really well-executed valve amp (with better Damping Factor).
The sound of the Cyrus 200 is remarkably clean, but not in a cold or sterile way; it’s more like looking at a high-resolution photograph, amid a wall of grainy, noisy prints. It’s not a lifting of veils, more an increase in precision and accuracy. Play something pure of tone – like Kat Edmonson’s voice on ‘Lucky’ from her Way Down Low album [Okeh/Sony Masterworks] – and you are rewarded with an extremely pure vocal free from any grain, hardness, edginess, or soundstage manipulation. The voice sounds as if it were physically ‘there’ between the loudspeakers, with the only real limitations coming from the loudspeaker boxes. You quickly begin to realise this ‘thereness’ holds throughout, but it also comes from the midrange out.
The Cyrus 200 is not mid-forward, and there is no emphasis toward the midrange. But it is an amplifier that delivers a noticeably great midrange, while the frequency extremes are in the very good class. Bass is surprisingly deep and potent for so lightweight an amplifier (normally that much clean bass needs a lot of reservoir capacitance and a far bigger power transformer) – a bass that is good enough to bust out ‘Handsworth Revolution’ from the Steel Pulse album of the same name [Virgin]. Here, the combination of roots reggae beat and dub bass depth has great presence and intensity. This album practically defines ‘phat’ bass decades before the term was coined, but can only do that to its fullest extent with a system that has excellent depth and control. It’s here where the tube amp sound analogy breaks down, but in a good way, because few valve amps have the ‘grip’ of the Cyrus 200.
Where this valve amp comparison hits home is in soundstaging. The Cyrus has a rare and valuable sense of three-dimensionality in its imaging that normally comes from the thermionic end of the amplifier spectrum. And yet, unlike thermionic valves, the Cyrus 200 is state of the art and relatively cool running in use. The live Shostakovich and Tchaikovsky piano trios played by Argerich, Kremer, and Maisky [DG] are a fine example of this soundstaging at work, in that you get a sense of the physical stage itself, and of three artists playing to a live audience through ambient information. As this is a late 1980s DG recording, this trio work isn’t like an audiophile pressing that could make a 3D soundstage when played through a transistor radio, so the fact the Cyrus 200 pulls as much staging information out of the recording is a sign of something good.
The acid test of a Class D design, and especially a design that includes impedance matching, is how well it works on a range of loudspeakers. More importantly, can it move from loudspeaker to loudspeaker with the ease of Class AB designs? The answer is ‘yes’, but a qualified ‘yes’, and fortunately for Cyrus, that qualification rarely applies in the real world to the kind of loudspeakers used on the end of a power amplifier at the Cyrus 200’s price point. There is no sense of ‘random characteristic generation’ when moving between two different loudspeaker designs here; that ‘space, grace, and pace’ refined character holds true across loudspeaker designs. The Cyrus 200’s bête noir is really punishing impedance loads, but fortunately this becomes largely the stuff of reviewers torturing products for fun and profit: no-one sane is going to run a pair of old Apogee Scintillas, for example. Stay above four ohms, don’t get it wet, and never feed it after midnight, and your Cyrus 200 will be your friend for life.
I think Cyrus has nailed Class D with the 200 power amplifier. I’ve heard my fair share of Cyrus amplifiers in my time, and this one is at least up there with the best of them. But more than that, the Cyrus 200 is an important amplifier, because it shows what Class D can do without costing a small fortune. While I’ve ‘banged on’ about Class D here (partly because the technology still has to justify its place in the audiophile hierarchy), I suspect most people who hear this amp will simply buy it because it sounds damn good. Highly recommended.
Inputs: 2× RCA phono single-ended, 2× XLR balanced line, 12V trigger, MC-BUS input phono
Outputs: 4mm/spade/bare wire loudspeaker terminals, 2× RCA phono single-ended chain out, MC-BUS output phono
Power output (continuous @ 0.1% THD+N): 175W per channel (into 8Ω), 325W per channel (into 4Ω)
Connectivity: Full RS232 control provided to allow a suite of Stereo 200 to be connected together, MC-BUS to other Cyrus products
Inputs: RCA phono or XLR balanced, 12V trigger
Power supply: 475VA Toroidal transformer
Dimensions (H×W×D): 73 × 215 × 360mm
Finish: Black or silver
Manufactured by: Cyrus Audio
Email: [email protected]
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