Circle Labs A200 integrated amplifier
Circle Labs will be a new name to many, yet this Polish manufacturer has been producing high-end audio products since the latter part of the twentieth century. The two guys behind Circle Labs, Krzysztof Wilczyński and Krzystof Lichoń, took the company, whose core business is in the design and manufacture of scientific research instruments, into new territories by following their passion for hi-fi. Combining an audio division within a successful existing business is a great way of doing things, one that avoids the financial burden of creating a company from the ground up, and helps to keep costs down. This Krakow based brand currently manufactures three models: the P300 preamplifier, the M200 power amplifier and the A200 integrated amplifier tested here. All follow a similar design theme, which, although minimalist, looks stunning.
The A200 amplifier’s quoted power output is 120 Watts into eight Ohms and (200W into four Ohms). The power amplifier stage is a true dual-mono design, it has separate toroidal transformers and power supplies, with a quoted combined capacitance of 200,000µf. The power amplifier is based around JFETs, driving a bipolar output stage in push/pull mode. The preamp stage, however, incorporates vacuum tubes, a pair of Russian Genalex E88CC tubes were installed by distributor G Point Audio, with a further pair of Siemens 8100 in the box so I could indulge in some ‘tube rolling’, which, as I learned from my time with the Lampizator Baltic 4 can bring substantial benefits. Unlike the Baltic 4, which proudly wears its tubes on the top of the chassis, the A200’s pair of glass bottles are hidden under the top plate of the casing. Once I had located the little hex screws hidden in the recesses of the heatsink, swapping the tubes took a matter of seconds.
Whilst under the hood, I discovered a pair of what looked awfully like a pair of CR2032 coin batteries. It turns out these control the polarity of the valve mesh – or biasing. One tube and one battery are in-circuit per channel. The volume pot is a resistor ladder affair from Khozmo, who I had incorrectly assumed were Polish. As it turns out, Khozmo is a Polish currently based in Spain that manufactures amplifiers in its own right. The high-end relays used in this volume pot are said to offer greater precision and accuracy than traditional units; certainly, there were no complaints from me, although the clicking and slight signal interruption whilst turning the satisfyingly large volume control was quite distinct.
Battleship build
My review sample arrived in a flight case, which proved to be a good choice as the A200 weighs 23kg and has some very sharp edges to its heatsink. So much so that I chose to don a pair of rubber gloves before removing the amplifier from its foam-lined case. Apparently the latest generation models have rounded heatsinking. The casing is a thick gauge metal, which my magnet test suggests could be aluminium. The 15mm glass front panel is a work of art and really sets off the look of the amplifier. Greg from Gpoint Audio knows I like to keep fit; therefore never leaves remotes for me to operate their products, but I see from the manual that one is supplied to paying customers, which includes controls for volume, mute and display on/off. The remote is way to change the display and my sample was set to with the display off. I did learn that the display counts down after switching on while it performs safety checks and that the display shows the volume level and illuminates the front panel graphics. Aside from the volume pot, there is a similar-looking knob to switch inputs, of which there are four. The index points for each input light up when the amplifier is on despite the display being turned off.
The back panel of the A200 has a power switch next to the IEC mains input, one pair of WBT Nextgen speaker sockets per channel, a pair of XLR inputs and three pairs of RCA input sockets. From my understanding, the A200 is not a balanced design, so the Neutrik XLR inputs are featured for convenience rather than offering a balanced connection. Unfortunately, my Townshend F1 XLR cables are far superior to any of the RCAs in my arsenal, so I could not get a handle on whether those inputs sound superior to the XLR, but I would expect them to deliver much the same result. The centre top front of the casing has a standby power switch mounted on what looks like a brass plate. The A200 sits on three metal feet, which have some damping material on their underside.
Does the A200 sound as good as it looks?
This amplifier replaced my long-serving Moon 600i, which has a similar quoted power output to the A200. Aside from Moon’s own 641, which is far more expensive at £12,000, I have yet to have another integrated amplifier in my system that has bettered it in the areas I value most, so the A200 has a tough job on its hands. Whilst the A200 was with me, I had the magnificent Kerr K320 Mk3 speakers in the system, which proved a great match. My Melco N1 and Moon 780D DAC were used as a source, with some help from various Network Acoustics digital cables and filters and Townshend analogue cables. Titan Audio mains products were used throughout the system.
G Point Audio told me they had used this review sample of the A200 in their demo setup for several weeks prior to entrusting it to yours truly, so it should have been nicely run-in, however, I still found that it took a day or so to come on song. Initial impressions, via the stock tubes, were that the music sounded extremely natural but slightly less dynamic and open than via my Moon, with the bass slightly leaner in balance. Despite this, it proved an involving and analytical listening partner, which was very easy to listen to over extended listening sessions. Soundstage depth, height and width, along with the sense of the recorded acoustic of live recordings in particular, were all highlights. Of particular note was a CD rip of the Cowboy Junkies Trinity Sessions, on which the acoustic was deliciously palpable.
These initial listening notes were made with the Genalex E88CC tubes installed. With some initial trepidation, I removed the A200’s top-plate and replaced them with the Siemens ECC8100 tubes supplied by the distributor. The swap produced quite a profound effect on the performance of this amplifier. With the Genalex tubes, I would describe the balance as slightly restrained, but the Siemens valves turned it into something of a firecracker. The bass was now fuller and tighter, the soundstage more forward and whilst not technically larger, the extremities were better defined. The Kerr speakers are highly revealing and will show up any hardness or excessive brightness present in recordings and components. The tube swap meant the system was less forgiving of poorly mastered music, but in the majority of cases, the balance was now more to my taste.
The ability to tailor the character of the amplifier by tube-rolling is a neat trick and, in my view, means the A200 should suit many systems. The Genalex tubes help take the edge off nineties indie music but fans of the Red Hot Chilli Peppers witll want the Siemens tubes for albums prior to Californication (AKA the best ones – Ed) and the Genalex for that album and everything beyond. Equally, there was perhaps a little more texture and intimacy with certain music via the Genalex tubes, although this could be system-dependent.
Music via the A200, especially with the Siemens tubes, sounds fluid, textured, palpable and involving, and its soundstage is as good as that of any integrated amplifier I have experienced at home. Most of all, though, it just gets on and gets the best of whatever music you play through it. The balance is perhaps slightly on the lean side compared to my Moon 600i, which also has a little more grip over the lower frequencies; whilst this is more of an observation than a criticism, it could be something to consider when matching with other components in your system. It is one of those amplifiers that sounds good whatever the volume level. For sure all speakers will produce fuller bass as the volume level rises, but the amplifier remained consistently balanced and dynamic sounding at lower levels.
Moving over to some music performed with acoustic instruments, my Mofi SACD rip of Sketches Of Spain brought Miles Davis and his ensemble of the best musicians of the time to life in my room. Play this on the wrong system, and the horns can sound so piercing that they make you reach for the volume control. The A200 gave me all the detail, body and shine that I could wish for here, but the brass instruments sounded deliciously smooth and creamy and were accurately positioned within the cavernous soundstage. Moving over to a recent classical release, Sophie Ann Mutter’s Bach, Bologne, Previn, Vivaldi, Williams, streamed from Qobuz in 24/192 sounded as delicate, yet dynamic and vivacious as I’ve heard it via any amplifier, including some far more expensive models. Yet play something electronic and bass-heavy, such as Kerala Dust’s cover of Fleetwood Mac’s The Chain (Qobuz 16/44), and if the rest of your system is up to it, the delicious textures will flood your room in a seemingly endless soundstage. Here the bass was deep, controlled and powerful, but the amplifier never lost control of the Kerr speakers, which do require a firm grip. Again, despite this track having plenty of high-frequency information, the top end remained clean and well-defined at all times, even at neighbour-bothering volumes.
Circling the verdict
I knew this was going to be my kind of amplifier from my first series session with it, and I cannot think of any good reason why it won’t impress anyone who loves music as much as me. It doesn’t throw the music at you and shove it down your throat like some, but it can deliver sonic fireworks when the music demands it and sounds more transparent and involving than almost anything else I have recently tried at home. Looks are subjective, but the A200’s proved popular with all in our household, and the build quality is superb, especially considering that it’s from a low-volume manufacturer. This may be the best sounding circa £10k amp on the market, but it costs les than £6,500.00. If you are in the market for an integrated amplifier, I highly recommend you give the Circle Labs A200 a try; your ears, feet and heart will thank you for it.