Review | Kinki Studio EX-M1+ 215 WPC Integrated Amplifier

There was a time … not too many years ago, when Chinese-made hi-fi components were kind of looked down upon by Western audiophiles. Luckily, those days are going away fast as the Chinese have come on in leaps and bounds lately with cutting edge yet affordable components from digital-to-analog converters to amplifiers, speakers and even turntables.

In amplifiers, the days where quirky tube amps from companies like Yaqin and Cayin were all that one ever saw from China (not that they were necessarily bad) have given way to companies like Denafrips and Topping who sell state-of-the-art DACs at more than reasonable prices to the topic of today’s review, the EX-M1+ integrated amp from Kinki Studio.

Kinki Studio seems like a funny name for a really high-end amplifier company, but the name is deceiving (Kinki is the designer’s wife’s nick-name). This amp is anything but “kinky”.

It’s also a very basic device. Need a built-in DAC? A built-in phono stage? Perhaps a headphone jack? Then my advice is to keep looking. This amp is a line stage and a power amp only. You can connect up to four line-level sources, change volume, mute the output and dim the display, and that’s about it. What you do get is a world class integrated amplifier of uncompromising build and sonic quality.

Cosmetic Design

The EX-M1+ is a development of one of Kinki Studio’s earlier designs, the EX-M1. The plus differs from it’s older sibling by using higher quality parts and a refined circuit topology and it adds a preamp output and theater bypass. Of Chinese manufacture, the EX-M1+ certainly is, but the company takes full advantage of parts known the world over for quality. Among the well known international components used in this design are such stalwarts of the high end as Furutech, Alps, Neutrik and Xilinx, making it a true international effort. In appearance, the EX-M1+ is, what I call, of the “Swiss School” of audio design and it resembles the Goldmund Mimesis 27.8 preamplifier as well as several other preamps/integrated amps from companies such as Hegel and several others sold today. The look is a popular minimalist one consisting of a large front facia with two huge round knobs flanking a centrally located rectangular display. The display itself is a large blue LED alpha-numeric affair which shows selected inputs and outputs as well as volume units, output configuration and mute status. The display is dim-able, and in fact can be turned off almost altogether (I say almost because one pixel in the lower right of the display stays illuminated; ostensibly to alert one that the unit is still powered on). The huge (the biggest I’ve eve seen), machined knobs only select the input and adjust the volume. All other functions are handled by the machined aluminum (from a single billet) remote control (more about that later). Somewhat unusually, in the center of the front panel, under the unit between the front feet is a single push-button power switch. I almost forgot to mention this because I always turn the unit on and off from the remote control.

The heavy silver colored front facia (in the case of the review unit, it is also available in black) is “textured” by parallel horizontal grooves and looks quite upscale and elegant.  The dimensions of the unit are 430mm W x 125mm H x 370mm D (16.9” x 4.92” x 14.57”) and the unit weighs 25 Kg (55.16 lbs).

Rear Panel

From left to right, the back panel has a pair of 5-way binding posts for the right speaker, followed by  the right XLR “balanced” input over a toggle switch for AC filtering. Next are three gold plated, very high quality RCAs for the right channel unbalanced inputs. Below them are the right home theater bypass input RCA, and to the right of that is the right preamp output. At the very bottom, center is the IEC mains cable input. Further to the right is a mirror image set of I/O jacks for the left channel. Below the left channel HT bypass is a ground float toggle and below that are a couple of banana jacks for the chassis ground and another for earth (the earth jack is connected to the mains earth connection unless the float switch is in “float” position). This is helpful for eliminating any ground loops one might encounter.

Technology

The EX-M1+ produces 215 WPC into 8Ω and 400 WPC into 4Ω. Output for each channel is provided by a pair of Exicon MOSFETs mounted on a gold anodized heatsink. The entire output module can be easily swapped for a fresh one should anything go wrong. The amp is a dual mono design with separate power supplies (including toroidal power transformers) for each channel. Even the preamp board sports two separate power supplies which are independent of the power amp’s supplies. The preamp stage invites “op-amp rolling” as all are socketed. It’s beyond the scope of this review, but I have seen YouTube videos where people have replaced the unmarked op amps (I suspect, however, that these op amps are members of the Texas Instrument (formerly National Semiconductor) LME479XX family) with discrete circuitry designed to be direct replacements for IC op amps as supplied with this amp.

The consensus is, here, that this improves and refines the sound of this amplifier even further. When I can score some of these “discrete component” op-amps) I will give them a try and report…

Operation

The Kinki Amp is a line-level device only with four inputs. Three are unbalanced and two are “Quasi”-balanced (meaning that they are really unbalanced but sport Cannon Type XLR female connectors such as those used for balanced connections in case one is connecting a balanced source component). The inputs, marked one through four can be selected by either the left-hand knob on the front panel, or from the remote control unit. Also controllable from the remote are the mute button, display on/off/dim, theater bypass, and the output mode. The amp has three output modes: Output 1 (speakers), Output 2 (speakers ‘off’, preamp output ‘on’ (Excellent for driving a headphone amp (the EX-M1+ wisely, has none) and finally Output 1 + 2 [ostensibly to drive a subwoofer]). As mentioned earlier, the remote is CNC machined from a solid billet of aluminum with an aluminum back cover held to the main body of the remote by implanted magnets. The remote is powered by a #3020 “coin” battery, but strangely, one is not provided.

All functions can be controlled from the remote and the unit’s volume increases in increments from 00 to 100 “volume units” using an R2R ladder attenuator not a VCA.

This reviewer powers a pair of speakers and a pair of headphones through an external amplifier with the Kinki Studios amp and finds the ability to turn off the speakers and turn on the headphone signal (or turn on both) from the remote to be a great advantage.

Equipment Used For This Evaluation

In order to provide some context for this review, let me list the equipment set up used here.

• Turntable – Thorens TD160 MK II ‘Super’ with custom power supply.
• Arm – Mayware Formula 4 uni-pivot low mass arm. (A present from my late friend, the great J. Gordon Holt).
• Cartridge – Sumiko Songbird high output moving-coil.
• Phono Stage – Clearaudio Nano V2.
• Music Server Client – Auralic Mini.
• Digital Disc Player – Oppo 103.
• DAT Recorder/Player – Otari DTR-8.
• Reel-To-Reel – Revox A77 ½ track, 15 ips /7.5 ips (38 cm/sec/19 cm/sec).
• DAC – Denafrips Terminator +.
• D to D converter – Denafrips Gaia.
• Speakers – Martin Logan Aeon i electrostatic hybrids factory upgraded to Xstat specs from the Vista model.
• Headphones – Stax SR-L 300 electrostatic phones with HiFiMan amp/energizer.
• Cables – I don’t do “cable swapping” as I know that when cables change the sound, it’s because cables are passive and cannot add anything to the sound, they can only attenuate something. They sound different because different cable models subtract different things from the overall presentation. On the other hand, I do strive to use good quality cables of the correct type and impedance. My interconnects are, for unbalanced connections, either from MyCableMart.com or Blue Jeans while my balanced cables are from Mogami and Belden. For speaker cables I use two 6 foot runs of  “Silverback” (12 Ga, OFC, 256 strand) speaker cable terminated with high quality banana plugs from Sewell Direct.

Audio Performance

Right off the bat, let me say that this is a magnificent performing amplifier. It is almost unbelievably fast and transients sound more real than I remember ever hearing them. I have two other integrated amps, a Harman Kardon HK-900 (dual mono 150 WPC) and a Krell KAV300i (also 150 WPC) and this amp slays both handily.

Specifically, The EX-M1+ has a damping factor of more than 2000! This is practically unheard of,  even in amps costing many times the Kinki Studio’s very reasonable (some might actually say cheap) price of US$2800. The amp also boasts a signal-to-noise-ratio of 103dB. This produces an amp that makes NO sound of it’s own. Not any hum, not any hiss. Even with sensitive speakers such as Klipschorns, when no program material is playing you hear nothing, even with the volume advanced to what would be, ear splitting volume if music were playing. In other words, dead silence!  This lack of background noise makes the top end of the Kinki incredibly transparent.  When switching from one’s old amp to this new one, the quiet can make you think that the amp is not working, which can be startling. It’s as if you’ve been driving on a long trip and decide to pull into a service station to clean your windshield. After miles of watching the road through a film of grime, when you get back in the car and on the road, you are taken aback by how much clearer the view is. This is the effect with the EX-M1+. It is so much cleaner and clearer than the presentation to which you are used to listening, that it is startlingly addictive. When I first hooked the amp up, I couldn’t stop listening to it. I pulled out every CD, every Tidal® source and indeed, every record that I could find which would show the amp to good effect and was amazed by the sound over and over again. I heard details that I have never heard before, and listened to ambience die away into silence as if hearing it for the first time (which in many cases, I was!).

Soundstage on this amp is exemplary, no doubt due to the amps dual mono nature. Channel separation is superb so image specificity is exceptional, front-to-back is excellent as is image height. Images are extremely stable – even when listening to records. And that soundstage performance carries over to headphones as well.

I was once recording engineer for a large metropolitan symphony orchestra, and have many master tape copies (to DAT) of those performances. I used two Sony C37P cardioid microphones in an XY configuration suspended from overhead, and slightly behind the conductor. The result is a true stereo presentation with pinpoint image specificity. This type of imaging is rarely available on commercial recordings, as most classical record producers prefer (for some reason) to use omnidirectional mikes (which must be wide-spaced to achieve separation between left and right.) This does not result in the best image specificity due to the lack of phase coherency between the mikes. When I play these recordings through the EX-M1+, the instrumental images are so palpable that it gives me goosebumps. I can literally close my eyes and point to every instrument in the ensemble. While my dual-mono Harman Kardon amp can do this to an extent, the Kinki amp renders these instruments in a much more three dimensional space. The HK reveals the images in bas relief, while the Kinki Studios amp fleshes them out, completely separating the instruments from their background.

Also, partially, I think, to the low noise floor, the top end presentation of this amp is neither too hot nor too cool but like Goldilocks’ porridge, I found that with this amp, it’s “juusst right”. On the relatively new release from Brubeck Editions records of the album “Time OutTakes”, we are treated to alternate takes from the famous 1959 album “Time Out” sessions. This new mastering of cuts captured at the same time as those in this jazz classic, we can see how recording and mastering technology has improved in the ensuing 62 years. For instance, Take Five, probably one of the most famous jazz tracks ever released, begins on this take, anyway, with rim shots and cymbal brush strokes from drummer Joe Morello. On other amps it is hard to distinguish that the rim shots are simultaneously accompanied by the brushed cymbals, and even though I have owned the original release of this famous album for many decades, I never noticed this (and frankly I’m not even sure it’s there on the released take!). But the Kinki’s clean, incredibly quiet top end makes it instantly apparent what’s going on here with this percussive introduction to Take Five.

Moving to the midrange, it is, compared to my Harman Kardon HK900, a bit on the cool side and I could wish for some more warmth, but it may be because I’m used to much warmer mids on my reference amp. On the Verve album, “Getz/Gilberto”, Astrud Gilberto’s voice on the famous cut The Girl From Ipanema seems to have stepped back a couple steps from the virtual “stage apron” in order to give us her breathy and sexy Portuguese accented English lyric.

The bottom end of the EX-M1+ is beyond reproach. With a damping factor of 2000, one would expect this amplifier to grab the woofer with it’s teeth and hold on like a snapping turtle (am I mixing my metaphors here? Turtles don’t have teeth, but they are tenacious) and it does! The bass is articulate, well controlled and deep. When the organ speaks It’s full C Major chord in the second movement of Saint-Saens “Organ Symphony #3 in C minor” (Michael Stern, Kansas City Symphony, on Reference Recordings) It has real authority, certainly, but one can easily hear the separation between the wind chest chuff  of the organ and the actual bass note. Most amps can’t do this as well as the Kinki Studio amp because the bottom end is not that well controlled. This is impressive.

Another reviewer/designer friend of mine (who’s ears, I trust) had occasion to compare an EX-M1+ to the $40,000 D’Agostino integrated amp and said that the Kinki was “at least as good”. High praise indeed, but I can’t really vouch for it because I haven’t heard it, but if they are even comparable then the Kinki Studio EX-M1+ is punching W-A-A-Y-Y above it’s weight class! At this price or at even twice this price this no-frills amp just has to be highly recommended! I’m keeping this one.

Product Details:

Manufacturer: Kinki Studio

Product: EX-M1+

Price: $2,898

Documents: Kinki Studio EX-M1+ User Manual (PDF 557 KB)

Links: Kinki Studio