KECES Audio

S4 Preamp & S300+ Power Amplifier

USD $3,999.95 (S4 Preamp) / USD $3,499.95 (S300+ Power Amp)

KECES Audio of Taiwan is unlikely to be a familiar name to most audiophiles. However, the company was founded in 2002, and its affiliate – Hui Kang Electronics – has a long track record as an OEM producer. The company says it aims to make high-end audio accessible to audiophiles with affordable equipment that offers excellent sound and elegant design. Apart from amplification, the company produces AC power products, DC power supplies and digital audio sources. The S4 preamplifier and S300+ power amplifier are part of the Superior Series, the company's flagship line.

UP CLOSE

The S4 is a two-box preamplifier with a zero-feedback circuit and symmetrically laid dual-mono circuit boards. Its cases share identical dimensions at 300 x 66 x 279mm and weigh 4.5kg for the power supply and 3.5 kilograms for the preamp. A rotary knob on the right controls the 128-step discrete resistor volume control and input selection. Two small buttons operate the mute and LED dimmer switch; the latter did not dim the blindingly bright power supply light, which makes its utility questionable. A small toggle switch on the left switches off the preamplifier circuit to provide optimal sound quality when using headphones. The headphone amplifier is balanced, and a single 4-pin XLR socket is provided. A full-metal remote control is also supplied.

Turning to the rear panel, you realise this is no ordinary preamplifier. The phono stage has two pairs of RCA sockets, one for an MM/MC cartridge and another for optical cartridges. The optical stage was designed in conjunction with DS Audio. Optical cartridges utilise a shading plate and light source to detect movements of the cantilever instead of a moving coil or magnet. This results in extremely low moving mass and theoretically superior sound. The local dealer supplied me with a DS Audio DS 003 optical cartridge to try this. For conventional cartridge users, a series of dip switches allow you to choose between MM and MC and adjust loading settings for moving coils. For line-level users, the S4 parsimoniously provides only a single set of RCA inputs but, thankfully, two XLR inputs. Both single-ended and balanced outputs are provided.

The S300+ power amplifier is a refresh of its predecessor model with an improved damping factor from 1,500 to 4,000 and upgraded internal materials and binding posts. The heart of the amplifier features a 1.2 kVA toroidal power transformer with independent secondary windings and power supplies for each channel's input, driver and output stages. A massive 65,000 uF filter capacitor bank should ensure plenty of power reserve, and the S300+ is specified to output 45A of peak current. The dual-mono design centres around a J-FET input and MOSFET output stages. The signal path is directly coupled, with no capacitors or inductors in the signal path.

Both single-ended and balanced inputs are provided, and three toggle switches control the input, bias mode and bridged/bi-amp mode. The bias mode allows the S300+ to be used in either Class A mode (5 watts) or Class AB mode (130W into 8 ohms or 225W into 4 ohms). Bridged operation straps both channels together to create a mono amplifier, increasing power to 410W into 8 ohms. WBT Nexgen binding posts complete the picture. Both the S4 and S300+ have 12V trigger sockets.

The S300+ measures 300x133x279mm and weighs in at 14kg. Placement of the KECES gear could prove tricky for some. The S4 boxes were too big to be placed side-by-side, and the stacked boxes were too tall to fit most of my racks. Similarly, a pair of S300+ power amplifiers couldn't fit on the same shelf. In the worst-case scenario, a fully tricked-out setup will eat up four shelves. Otherwise, the installation and operation of the KECES proved uneventful. I found the S4 to run hotter than the S300+, idling at 44.5C or 20C above ambient temperature. The S300+ reached 41C in low-bias mode and 42.5C in high-bias mode, so I wouldn't install these in a closed cupboard.

The amps were paired with an SOtM sMS-200 ultra streamer, ii Pro iDSD DAC and Tannoy Kensington GR speakers. The analogue rig consisted of a Luxman PD-171A turntable, a Denon DL-103R MC cartridge and the aforementioned DS Audio optical cartridge.

THE LISTENING

This KECES combo casts a wide and precise soundstage with astounding bass power that's remarkably tight and tuneful. For example, listening to Bye, Bye Blackbird by Ray Brown, John Clayton & Christian McBride confirmed that this combination is an absolute bass monster. Thankfully, the bottom end was agile and detailed, with deft fingerwork reproduced faithfully. On lesser systems, this track may sound muffled or homogenous.

Eva Cassidy's What A Wonderful World is an excellent showcase for her pure and crystalline voice. This live recording at the Blues Alley is a good test of system transparency with Cassidy's wide vocal range and the background noise from the audience. However, great systems can also reproduce faint tape hiss, sibilance from vocals, and overloading of the recording at some points. The KECES is not into flattery and was able to reproduce this recording faithfully, warts and all.

Likewise, Within You'll Remain by Sandy Lam is a delightful cover of the song made popular by Tokyo Square in 1985. This track has a simple arrangement with Sandy, backing vocals and acoustic guitars. The KECES conveyed her delicate and almost breathless voice accurately, while the guitar solo sounded crisp with the right balance between the incisive pluck of the string and the decay of each note.

This combo brings delicacy and intensity together in an effortless way. It sailed through a rendition of Brahms' Sonata for cello and piano No.1 in E minor, Op. 38. Allegro performed by Helene Grimaud and Sol Gabetta. I could clearly hear the changes in mood and expression throughout the piece. The playing mirrored the qualities of the KECES amplification, switching between nuance and power while remaining firmly in control at all times.

The KECES' star shone the most brightly in its ability to recreate space, whether that of the recording venue or reproducing the air around instruments and vocals. I was able to hear each sound and how it energised the acoustic space around it. This rare quality eludes most solid-state equipment except at the highest echelons of the hi-fi pyramid, so this is really high praise in my books.

As for the S4's phono capabilities, using the DS Audio optical cartridge almost spoiled my ears with its low noise floor and fine detail, a quality that eluded my Denon cartridge. The price of most optical phono stages exceeds the S4, making it rather cheeky of KECES to include this here. The conventional phono stage was no slouch either, being the equal of a good dedicated off-board type. The Denon cartridge sounded great, with music coming across as dynamic and open. I especially liked how the S4 sounded so neutral, matching the quality of its line stage.

Headphone users should enjoy the S4, too—there were no issues driving my Audeze LCD2s, Drop HD8XX, and Dan Clark Audio Aeon Closed headphones. It's a pity that a conventional 6.3mm socket was not provided, as this excludes a large segment of headphone users. While sonically good, the quality of the headphone stage was not as impressive as the S4's excellent phono capabilities.

I tried the S300+ briefly in high-bias mode. While there was a pleasant smoothness to the midrange, the sound lacked the confidence, grip and resolution of the low bias mode. This will be loudspeaker-dependent, and better results may be obtained with more efficient speakers. But bridging the S300+ transforms it into a different beast. The sound takes on a more dynamic and forward tone. Soundstaging precision and the separation of instruments also improved a few notches. I missed the more relaxing presentation of the stereo S300+, though, but this may be worth exploring if you have very hard-to-drive speakers or like your music served with steroids. The sweet spot for me would be the S4 with a stereo S300+.

THE VERDICT

KECES Audio S4/S300 pre/power amplifier is a cracking combination. Personally, I believe the star of the show is undoubtedly the S4 preamplifier. Offering outstanding sonics and a fine phono stage, it seals the deal with support for optical cartridges and a decent balanced headphone amplifier at a bargain price. The S300+ ably supports the S4 in its mission, delivering a largely transparent signal to speakers with steadfast composure into the most demanding loads.

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