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AMR’s Continuous Calibration Multibit “CCMD” DAC
At the heart of the CD-777 Processor is AMR’s ‘continuous calibration’ Multibit Digital-to-Analogue Converter circuit using the Philips UDA1305AT Multibit Chipset. This is the first time this New Old Stock chipset has been used in a CD source and is worthy of the title “son” to the “King of Multibit” Philips TDA1541A chipset used in the multi-award winning CD-77. With AMR’s understanding of digital design down to the silicon die-level, the sonic performance of this “Prince of Multibit” chipset has been taken beyond the textbook limit. Producing visceral music that other mega-buck CD players cannot match, it must be heard to be believed. Along with AMR’s OptiSample, the CD-77 boasts full remote control of all sampling modes: Direct Mastering (AMR’s custom Non-Oversampling), Oversampling (2X, 4X) and Upsampling (96 kHz, 192 kHz).


Over the last few years, the pace of progress of computer-based audio has continued unabated. So much so that AMR has developed a proprietary solution: OptiCompuAudio® which allows the CD-777 to become a dedicated CD-Transport or Digital-To-Analogue Converter through either USB or S/P-DIF without a commensurate rise in jitter (unlike virtually every other approach). Underpinned by AMR’s OptiClockLock system using a proprietary TXCO clock, the result is external or computer-based audio that is at the level of direct CD playback.


OptiSample® offers the best possible performance for CD replay. AMR appreciates that “no one sound fits all”. Hence, the CD-777 offers different sampling approaches from Digital Master to Oversampling to Upsampling. They are all user-selectable, offer different perspectives on the sound and reproduce the original recording to the highest degree. Most important of all are Digital Master I and Digital Master II which were developed by and are exclusive to AMR. With these two modes, the CD-77 and CD-777 are able to play "bit perfect" audio. This means music, not hifi is the outcome as there is no artificial manipulation of the signal."


Going against the grain, AMR believes that having the ultimate in digital execution would count for little if the analogue section was not just as dedicated. Hence, the analogue section of the CD-777 utilises AMR’s OptiValve® analogue stage with zero negative feedback and 6H1n-EV valves. The “EV” designation represents the premium version of this valve. As these are a double triode per channel, one half amplifies and the other buffers. Rectification and filtering in the CD-777 uses low-noise, solid-state diodes with additional noise filtering and an electronic inductor instead of copper wire wound around iron. While simplified in execution and with slightly less elaborate power supplies, the analogue stage of the CD-777 is identical in basic concept and function to that of the CD-77. With no operational amplifiers or solid-state devices, this is a major factor behind the CD-777’s organic and “vinyl-like" music performance that will embarrass many a high-end CD player at even up to five times the price.


AMR’s expertise in specialised transformer design for audio use has led to the development of transformers with individual windings which offer the sonic benefit of individual transformers without the space required for separate transformers. Again, AMR has shunned the mainstream (and more cost-effective) approach to the use “off the shelf” transformers, preferring to have its own dedicated transformers hand-wound and hand-made. Power supply is an integral part of circuit design and AMR’s steadfast approach has ensured the highest possible quality of music performance.


The OptiDrive® transport mechanism is an in-house, ground-up design. The musical synergy was made possible through using the best genuine components - the high-precision, reliable Sony K-series laser pickup mated to the musical Phillips CD-18 servo system along with a proprietary high-torque direct-drive motor. The laser is constantly bathed in blue LED lighting to maximise the sonic performance. The software is bespoke by AMR to extract the maximum performance.

Unconventional, Dedicated Components

Underpinning the design behind each and every AMR component is the use of premium components which were chosen after judicious evaluation and extensive listening tests. These include silver leaf capacitors, Sanyo Oscon capacitors, precision wire wound resistors, 70um gold plated, military-grade printed circuit boards, German-made premium film capacitors, AMR's own power supply polypropylene film Music Capacitors and zero-noise Schottky rectifiers.

It is worth noting that such lavish components are seldom found in five-figure digital sources yet are found in the CD-777.

Information and specifications subject to change without notice.


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