KI Ruby: 40 years at Marantz : Page 2 of 2

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KI Ruby: 40 years at Marantz

As those familiar with the program will know JRiver is the Photoshop of music (and video) players with many set up options that have a direct influence on sound quality. Ken has apparently listened to most of them and shared some of the more important ones, including his finding that minimum buffering gives best results. The KI approved options are:

WASAPI driver
Load decoded file into memory
Bitstreaming for DSD
Prebuffer: 2 seconds


We listened to a variety of music styles including one piece chosen to reveal the characteristics of the large room which had unusually open highs and clean, even bass. The results were pretty impressive with Sinatra's ‘It was a very good year’ being a stand out, things managed to get more interesting when the source was switched to a Clearaudio built Marantz TT-S1 turntable with MC cartridge running through the phono stage in the PM KI Ruby. It was probably the record, Quincy Jones’ The Dude, or switching to a more central seat further away from the system but this track made a good case for Ken’s assertion that “CD is for business, vinyl is for fun!”

PM & SA Ruby
Following on from the KI Pearl of ten years back the new PM KI Ruby integrated amplifier and and SA KI Ruby SACD player are limited to a production run of 1000 units of each in Europe. With 500 black and 500 gold units carrying serial numbers that reflect the finishes, odd numbers for black even for gold. The PM KI Ruby has a 100 Watt class D output stage and an active preamplifier stage each with its own power supply, making it effectively a pre/power in one box. It has analogue only inputs and a separate headphone amp plus source direct, it also has a rather special phono stage for both MM and MC cartridges. This is a discrete, cascaded design with an initial gain stage for MC that acts like a head amp before the EQ stage, apparently it’s better than the phono stage in the PM-10. Input stages are JFET operated with no coupling caps and the HDAM op-amps in the second stage have been designed without global feedback. It differs from most Class D designs by virtue of putting the feedback after the output filter, a design created by an unnamed Belgian engineer (Bruno Putzeys?) which means that the filter is no longer interacting with the load presented by cable and speaker.

The SA KI Ruby CD/SACD player is where the digital inputs reside, this is both a disc spinner and a DAC and was demonstrated in the latter mode. It has the new Sound United (the parent company) metal drive mechanism which will play DVD-R discs with FLAC, WAV, DSD etc files as well as regular discs. The USB-B input is capable of up to 32-bit/384kHz PCM and DSD246, there is also a USB-A input for thumb drives and phones. The DAC at the heart of this machine uses integer upsampling to convert all incoming PMC signals to DSD prior to conversion. You can choose between sharp and slow roll-off but Ken prefers the former which is naturally the default mode. 
Both KI Ruby units will retail for £3,500 and will be available this month.