Marantz has been designing and manufacturing high-end amplifiers for over 65 years, 40 of which have been under the direction of Ken Ishiwata. Now, to celebrate his 40 years with the company, we introduce the PM-KI Ruby, which was designed and tuned by a team of highly skilled engineers under the direction of Ken Ishiwata himself.
The Marantz PM-KI Ruby amplifier is built with one thing in mind – delivering high audio performance, so it uses a fully discrete two-stage design with separate power supplies for the preamp and power amp sections, and draws on the design of the flagship PM-10 amplifier with its MM/MC phono section featuring Marantz Musical Premium Phono EQ technology, as well as proprietary HDAM power modules for signal purity.
The circuitry offers the purest signal path through the amplifier, delivering 100 watts per channel into 8 ohms or 200 watts per channel into 4 ohms, plus high-quality nickel-plated input terminals and high-purity copper speaker posts. All of this is built on a vibration-resistant dual-layer chassis, with thick aluminum panels for rigidity, and adorned with Ken Ishiwata’s engraved signature to set this very special amplifier apart.
The Marantz PM-KI Ruby power supply unit has a high-power toroidal transformer placed in a protective screen. The amplifier circuit is made according to the dual mono scheme, using selected audiophile-grade components and proprietary HDAM modules of the S3 version. It is three-stage, including a preamplifier stage and two power amplifier stages. The output stage transistors are mounted on massive cooling radiators inside the amplifier case, so the appearance of the device is neat and strict. As a result, it was possible to minimize the length of the audio signal transmission paths, which had the most positive effect on the level of distortion and noise. In addition to line inputs, the amplifier is equipped with an innovative phono preamplifier from Marantz Musical Premium Phono EQ, borrowed from the flagship PM-10 amplifier for working with vinyl disc players. It is designed for the most modern models with moving coil (MC) and moving magnet (MM) pickup heads. The combination of current feedback with a newly developed wide-band component base, the use of hyperdynamic amplifier modules HDAM-SA3 and a new linear volume control in the design of PM-KI Ruby provides power, clarity and optimal dynamics of sound.
The amplifier is equipped with three linear unbalanced inputs, a balanced input, inputs / outputs for two recording devices, and an output from the preamplifier. You can connect one pair of speakers to the Marantz PM-KI Ruby amplifier, and its front panel has an output for stereo phones. The device is made on a copper-plated chassis, reliably protecting its electronic circuits from external electrical interference and mechanical vibrations.
Careful tuning has long been the secret to the superb sound of Marantz amplifiers, and for the PM-KI Ruby, Ken Ishiwata and the company’s engineering team have applied all their experience and expertise both in the amplifier’s design and in the long listening sessions that follow to finalise the sound. As you would expect from a product celebrating a 40-year career, the PM-KI Ruby is a real cause for celebration and a perfect embodiment of the Marantz slogan “Because music matters”.
Marantz PM-KI Ruby Specifications
Output Power 2 x 100 W (8 ohms); 2 x 200 W (4 Ohm)
Frequency response 5 Hz – 50 kHz Total
harmonic distortion 0.01%
Damping factor 500
Signal-to-noise ratio 107 dB (preamplifier, at 2 V input), 88/75 dB (MM/MC cartridges, phono equalizer)
Input sensitivity/input impedance when using the line inputs of the preamplifier 220 mV/13 kOhm (RCA)
Input sensitivity/input impedance when using the direct input to the power section 1.1 V/13 kOhm
Sensitivity/impedance at the phono equalizer input 2.3 mV/39 kOhm (MM), 250 µV/100 Ohm (MC)
Discrete amplifier modules HDMA SA3, SA2
Inputs 5 line RCA (including CD input with nickel-plated RCA connectors and 2 inputs for recording monitoring), RCA connectors MM / MC phono preamplifier (nickel-plated), RCA input to the final section
Outputs 6.3 mm for headphones, 2 RCA for recording
Other 2 connectors for the D-Bus system bus, 2 connectors for connection via the FCBS bus, ground terminal
Phono preamplifier MM / MC, Marantz Musical Premium Phono EQ Speaker
output 2 pairs of high-quality Marantz SPKT-100+ screw terminals (highly purified copper)
Power supply linear for the pre-section (toroidal transformer), pulse for the final section
Power consumption 130 W, standby: 0.2 W
Remote control universal RC005PMSA
Dimensions (WxHxD) 440x127x453 mm
Weight 15.7 kg