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Marantz has been designing and making amplifiers for more than 65 years, and for 40 of those the products have reflected expertise of Ken Ishiwata. Now, to mark his four decades with the company, the PM-KI Ruby amplifier has been developed and tuned by a highly experienced engineering team led by KI himself. It features a fully discrete two-stage design with separate power supplies for the pre-amplifier and power amp — plus, a moving coil/moving magnet phono stage complete with Marantz Musical Premium Phono EQ circuit and Marantz HDAM technology for signal purity and exceptional audio quality. PM-KI Ruby is built on a vibration-resistant double layer chassis with thick aluminum panes for rigidity and features a laser-engraved Ken Ishiwata signature to commemorate his legacy.
Celebrating 40 Years of Passion
Designed to celebrate the 40-year anniversary of legendary Marantz sound master, Ken Ishiwata, PM-KI Ruby features pinnacle performance that’s synonymous with Marantz excellence. Complete with thoughtful engineering, painstaking tuning and extensive listening sessions, PM-KI Ruby achieves the elevated output worthy of its name. Elegantly shows Ishiwata’s laser-engraved signature to commemorate the design and heightened listening experience that honours the decades-long partnership between him and Marantz.
Led by Ken Ishiwata’s extensive, meticulous approach to tuning, the larger Marantz engineering team applied more than 65 years of experience and HiFi knowledge to create PM-KI Ruby, resulting in a final product that is a testament to Ken Ishiwata and the Marantz legacy.
Marantz developed its own discrete circuit boards called Hyper-Dynamic Amplifier Modules, or HDAMs, to replace the chip-based amps used elsewhere. Using discrete surface mount components with short mirror-image left and right signal paths, HDAMs outperform the regular integrated Op-amps dramatically in Slew Rate and noise level. The result is much more dynamic, accurate and detailed sound. Over the years, Marantz has developed different HDAMs to fit the particular requirements of players and amplifiers. The PM-KI Ruby uses the latest high-grade SA3 version. Combined with optimized circuit design layout and carefully selected components, the PM-KI Ruby provides exceptional sound quality and performance.
Marantz Musical Premium Phono EQ
Designed to deliver optimal sound quality by simplifying the signal path, the Marantz Musical Premium Phono EQ stage in the PM-KI-Ruby amplifier can be used with both moving magnet and low-output moving coil cartridges, thanks to a built-in MC head amplifier. Distortion is reduced by using two-stage amplification in the phono stage, and Marantz HDAMs are combined with JFETs (junction gate field effect transistors) in the input stage, giving high input impedance. The exclusion of coupling capacitors further simplifies the design, reducing signal distortion and enhances signal purity.
High Quality Volume Control
Newly developed electric volume control uses the latest volume control IC to realize better channel separation, dynamic range and distortion-reduction, while retaining the operational feel of an analogue volume control device. The amplifier employs new Marantz-designed electric volume control for high linearity and best-in-class channel separation.
Current Feedback Amplifier
Current Feedback amplification is a well-known, Marantz-original circuit technology, thoughtfully designed to match the requirements of Super Audio hi-res music for wide-bandwidth, high-speed reproduction. The impedance at the Current Feedback point is limited, generating a very low phase shift. Marantz Current Feedback amplifiers reduce the need for phase compensation by minimizing Negative Feedback (NFB). This simplifies the signal path and results in a high through-rate, excellent transient response and superb sonic transparency across the full bandwidth. Unlike conventional Voltage Feedback topology, Current Feedback also makes the power amplifier insensitive to difficult loudspeaker loads.
Balanced Power Amplification
Drawing on design elements of the PM-10, the PM-KI Ruby is built to leverage enhancements, maintain the purest possible sound and support the power needed to drive the most demanding speakers. The amplifier output stage of the PM-KI Ruby allows a large power output, delivering 2x100W into an 8ohm load, and easily copes with high-impedance speakers thanks to a 2x200W output into 4ohms. The amplifier module connects directly to the rear panel PCB on the PM-KI Ruby to maintain signal purity and sound stability.
The purely analogue design of the PM-KI Ruby contributes to its noise-reduction structure and clean build. Rather than build the DAC into the amplifier, which would add noise within the chassis, Marantz built the PM-KI Ruby without one and then implemented the DAC in the SA-KI Ruby Super Audio CD Player. This eliminated interference with the delicate analogue signals passing through the amp, maintaining an analogue environment that’s as pure and clean as possible.
Carefully Selected Components
Marantz has a steadfast reputation for choosing the best-possible components for its Premium Series products. The Marantz alternative to the “amplifier on a chip” IC components, the HDAM, is a miniature amplifier module built entirely of discrete components. Marantz engineers selected and optimized the HDAM through extensive listening in dedicated Marantz facilities in Europe and Japan. Extensive, painstaking and meticulous tuning has long been the secret of exquisite-sounding Marantz amplifiers. During the development stage, every part is carefully selected, tested and validated by Marantz audio engineers to ensure audio perfection every time you listen.
Multiple Analogue Inputs and Outputs
In addition to phono and CD analogue inputs, the PM-KI Ruby features two line-level inputs and two pairs of recorder input/output jacks that enable the connection of multiple sources and recorders. Use the PM-KI Ruby as a standalone stereo power amplifier for additional system configuration versatility with the included power amp input, or connect the PM-KI Ruby to an external power amplifier via the stereo pre-amp outputs.
Dedicated Headphone Output
Using Marantz-proprietary HDAM discrete modules, the headphone circuit delivers superb audio fidelity with the widest range of headphone types and impedances, including low impedance headphones.
System Remote Control
Use the elegant remote control to operate the PM-KI Ruby as well as the complementary SA-KI Ruby Super Audio CD Player. The PM-KI Ruby features remote control input and output jacks for additional remote control configuration flexibility.
Like the complementary SA-KI Ruby Super Audio CD player, the PM-KI Ruby integrated amplifier is constructed to the highest standards with a copper-plated chasses to reduce mechanical and electrical interference. A front panel constructed from thick, heavy, non-magnetic aluminum panels and an 5mm dense aluminum top cover eliminate added interference. Nickel-plated copper independent input terminals for CD and Phono plus Marantz-original high-quality/high-purity copper-plated speaker terminals ensure the best signal possible.
Founded in 1953, Marantz has a long and rich history of designing audio components embraced by music lovers and critical listeners around the world. Because Music Matters, the PM-KI Ruby carries on our long tradition of delivering a best-in-class listening experience for music and cinema.
| Channels | 2 |
| Current Feedback Topology |  |
| Phono EQ: Standard / Marantz Musical / Marantz Musical Premium |  / / |
| HDAM version | SA3, SA2 |
| Power Transformer: Toroidal / El | SMPS |
| High Grade Audio Components | |
| Customised Components | |
| Symmetric PCB Layout | |
| Aluminium extrusion heat sink | (Separate) |
| Copper plated chassis | |
| Balance / Bass / Treble / Loudness | / / / |
| Linear Drive Power Supply | (pre-amplifier stage) |
| Liniear volume control | |
| BI-AMP and Multichannel option | |
| Shottky diodes | |
| System block shielding: copper / metal / none | / / |
| Double Layer Bottom Plate | |
| Low Noise OELD display | |
| 5mm aluminium top plate | |
| Audio Inputs | 6 |
| Phono Input: MM / MC | / |
| Audio Outputs | 2 |
| Power Amp Direct IN | |
| Gold Plated Cinch | / CD & Phono nickel-plated |
| Speaker Terminals | Marantz SPKT-100+ |
| Number of terminals | 2 |
| D-Bus | |
| Floating Control Bus (3.5 mm mono jack x 2) | |
| Headphone Out | |
| Power Output (8 / 4 Ohm RMS) | 100 W / 200 W |
| Frequency Response | 5 Hz 50kHz |
| Total Harmonic Distortion | 0.01% |
| Damping Factor | 500 |
| Input Sensitivity: MM | 2.3 mV / 39 kohm |
| Input Sensitivity: MC | 250 |
| Signal to Noise Ratio: MM / MC | 88 / 75 dB |
| Input Sensitivity: High level | 220 mV / 13 kohm |
| Signal to Noise Ratio: High level | 107 dB(2V input/Rated output) |
| Available colors: Gold / Silver / Black / Silver-Gold | / / / |
| Metal Front Panel | |
| Power Consumption in W | 130 |
| Standby Consumption in W | 0.2 |
| Auto power off | |
| Detachable Power Cable | |
| Remote Control | RC005PMSA |
| System Remote Function | |
| Maximum Dimensions (W x D x H) in mm | 440 x 453 x 127 |
| Weight in kg | 15.7 |
