Like the A200 integrated, the M200 dual-mono power amplifier is a hybrid. Externally it differs little so fit 'n' finish are just as exceptional and gorgeous. The obvious main difference is lack of knobs on the glass front. Lateral heat sinks combine with mesh-sealed top vents to ensure proper ventilation of circuits and tubes. The chassis measures 43x36x18cm, weighs 20kg and rests on the same three footers as the preamp. The rear panel features Nextgen WBT posts and balanced/unbalanced inputs. An additional solo XLR becomes the mono input. Key to increased power output (600/900w into 8/4Ω over 160/300wpc stereo) is a true-balanced input signal. The P300 preamplifier offers both balanced and unbalanced inputs. The latter don't symmetrize to send the amp an unbalanced signal even over XLR. Now even mono will produce 'just' 160 watts. To fully exploit a duo of M200 relies on a front-to-back balanced signal path. The latest addition to the amp are channel-specific 0, -3 and -8dB gain toggles for speaker matching. Its input stage sports NOS 1960's Siemens triodes for voltage gain. Battery power allows a minimal gain stage of one tube, one resistor and one top Mundorf silver/gold capacitor for an ultra-compact signal path of peak performance parameters. Called Circle Power, the output buffer of high-spec Sanken current-coupled bipolars is said to be closest to single-ended designs whilst being groomed for maximum efficiency and power. Custom-built power toroids are spec'd for 850 watts total. The tube inputs get a copper-insulated EI-core transformer and their own discrete power paths. Total capacitance for the output buffer is 200'000µF.

From my A200 review you know that I loved it; and hoped to add the separates to my reference system if they performed as expected. I own the excellent GrandiNote Shinai integrated and AudioFlight's impressive FLS1 pre but for a while dreamt of adding a dedicated power amp. I thought that not only might Circle Labs fill that gap but materialize another personal dream: to listen to an all-Polish system should the P300 acquit itself strong against my AudiaFlight. Due to high demand, it took Circle Labs a while to assemble my samples. Once they arrived, an opportunity arose for a short-term loan of a second amp to report on mono power with my sealed Ubiq Audio Model One Duelund Edition loudspeakers. I was excited about this chance as my personal stakes in this review were higher than usual. Would this become my dream set for the foreseeable future? Let's start with the P300 | M200 driving my GrandiNote Mach4 line sources. It wasn't their first encounter. I'd had a chance to preview the combo for a few days some months ago. At first I wasn't even aware of any changes they'd introduced in the interim. While the amp had won those gain switches for purely functional advantages, the preamplifier's upgrades were intended to shift its sonics. As it turns out, they did push the sound in a desirable direction.

Despite these changes, already within the very first minutes I heard familiar DNA of the A200 integrated. This design ethos turns the exceptionally attractive aesthetics into equivalent audiophile qualities for a super-compelling musical presentation. It generates an incredibly immersive experience so decidedly not what's commonly referred to as a highly analytical reading. It neither sounds cool nor does it focus on emphasizing individual audiophile traits. Instead it delivers the bigger picture by way of a deeply intimate experience. That reminds me of my favorite SET amplifiers; not by sounding the same but by pursuing the same holistic gestalt. It's exactly what I heard with a for me more recent discovery, Musica Nuda. Their albums begin by being technically really well recorded. Then many of them feature just double bass and vocals to be beautiful, intriguing and capable of holding our attention from start to finish especially when rendered in such convincing tube-reminiscent fashion. By that I mean an open, airy, pure yet rich, coherent, organic, palpable and particularly spacious sound which now combined with more power, superior drive and grander scaling.

Interesting was how the Circle Labs twosome presented even such intimate music in a spatially more distant way to not push the performers at the listener but rather build a large soundstage with palpable images placed well behind the speakers. It recreated the live paradox of feeling close to the performers while actually watching and listening to them from a distance. It's a rare quality only a few amplifiers I know pull off. Almost all of them are SETs. On my private list of favorite very live-sounding amplifiers, the P300 | M200 duo already at this early audition stage earned itself a spot amongst very very good company. Even though there are only two performers on this Musica Nuda album, they filled my room with big, palpable, highly expressive sound. The double bass reached low with power and weight but remained agile when needed. Timbre and textures were most convincing and conveyed the instrument's true size and nature of a resonant tone-wood body. Attacks were fast, sustain and decay elongated as they should. The gorgeous voice of Petra Magoni felt natural, organic and tangible. It presented intricate details so convincingly that it seemed as though she stood just a few meters from me while pouring her whole heart and soul into song. This was an exceptionally effortless, beautifully engaging presentation that left me in awe of the performers' skills and that of the Circle Labs engineers who had developed their set to allow music to come through in such touching and addictive fashion.