This review page is supported in part by the sponsor whose ad is displayed above
CES 2007 in the Las Vegas Venetian hotel casino saw the formal rollout of Abbingdon Music Research for the global audience. This exhibit was hosted by Darren Censullo of Avatar Acoustics, AMR's US importer who also distributes Franck Tchang's Acoustic System resonators and Karan Acoustics electronics. The latter made up one system with AMR's CD-77 and Franck's new Tango speakers.

A second system was set up catty corner for an all-AMR effort with a prototype of the firm's new monitor speaker.

AMR's unusual power transformers "breaking considerable new ground" for their supplier "due to the cores and the way the windings are sequenced to the number of independent sections" caused an unexpected time delay in the roll-out of initial production. During the process of dialing in fabrication of these parts, AMR further optimized the servo timing of the CD-77's drive control and "located a source for a far superior quality of clock generator for our master clock. During development and initial small-scale production, we had used a clock generator available also as part of one of the most respected, well-reviewed and -- in both objective and subjective terms -- excellent after-market "SuperClock" modules. We combined this clock with our own power supply and buffer circuit, which already significantly improved upon those available in the after-market modification module. Yet we found the new temperature compensated crystal clock to reduce the already low phase noise (which translates into jitter) by another factor of 10. The result were significant improvements in subjective sonics and this clock is exclusive to us and not to be found anywhere else."

The CD-77 travels in a no-nonsense flight case inside two shipping cartons to insure the hefty innards against shipping mishaps. This custom case included the player in the Platinum finish as requested; the custom touch-screen remote; a pair of custom silver-plated solid-core paralleled copper conductor ribbon RCA cables; a 1.5" meter custom power cord; two sets of prototype custom wooden footers with embedded crystals; a 19-track AMR System Test Disk with guided music demonstrations, mono pink noise, out-of-phase mono pink noise, a pink noise + sweep burn-in signal and a demagnetization signal; the magnetized CD puck; a Telarc The Divine Feminine CD; and a comprehensive owner's manual with quick setup guide.
The wooden footers and test CD weren't standard items - Vince had handed out the latter at the show and thrown in a leftover. But the Telarc disc is included with every CD-77 and AM-77, a very cool 16-track 55':34" long goodie of classical movements which the label has made available to AMR for this promotional purpose. Nice gesture, Telarc! Pleasant surprises continued. Because the machine's two lines of voltage designation were left unmarked to confirm universal compatibility [see above], I plugged the player into my 117V line. The blue display fired up fine but told me in no uncertain terms "AC voltage outside operating range!". Swapping to my 230V line commenced full boot-up with its 45 second warm-up displayed as a countdown. Needless to say, this OptiMains protection will also shut down the mains supply to the internal circuitry to protect against excessive under/over voltages from brown-outs, extreme power surges and other potentially lethal component catastrophies. AMR was just puzzled that their machine wouldn't automatically step down to my US voltage circuit so I measured it. That day, it was 134/135V, just at the edge of what the CD-77 would lock on to in its US AC power mode. Bloody smart power supply.

The system remote and display are complete custom solutions full of thoughtful touches. There's no silk-screening on the alu wand anywhere but only pure engraving (ditto for the player's front panel with its soft-touch buttons - and the chassis shows no screws on the top or sides). Remote commands trigger a verbal confirmation so 'next track' doesn't just jump forward but, for a few seconds, also displays in a second line of the display as 'next track'. Ditto for time displays, digital mode changes, repeat, scan, pause - in fact, anything you tell the player to do. Once you close the hatch, TOC read-in commences automatically while the read-out says 'loading disc". Total tracks are displayed quickly thereafter. Even 80-minute CDRs pose no problem. You can code the player to commence play automatically after loading. Or defeat that feature. Simply press the fascia's stop button simultaneously with the play/pause button on the remote to have it your way.

The fully suspended transport mechanism is bathed in blue light-emitting diodes and the solid lid deliberately locks out any ambient light. The inbuilt bubble level is a nice touch but the CD-77's footers are hard mounted and non-adjustable. If you use standard furniture as your component support, you'll know if you're out of true but won't be able to rectify it unless you shim up the player or credenza. AMR believes adjustable footers would negatively impact performance so lacquered rosewood shims will be included for those scenarios.
The rear apron sports the widely spaced RCA and XLR outputs, the USB input and an IR port for a wired remote. The plexi windows on the deep top use lateral slots for ventilation and emit a faint blue from internal circuit diodes. In toto, first impressions -- packaging, trim, size, weight, fit'n'finish -- suggest extremely rugged construction CEC style. Because opening up the player is a bit tricky -- unless you're careful, you'll knock out the latch door indicator since the whole three-piece top with the lid-on-rails comes off -- I played chicken and requested interior shots from the factory.

As promised from the extra time spent on the transformers, the CD-77 was mechanically dead quiet, exhibiting zero hum or buzz. Big and brutish this machine may be on the outside but everything thus far indicated quite the sophisticated innards.

By the way, the origin of the name Abbingdon Music Research is Abingdon, the Oxfordshire town which was the birthplace of the Mini rally car, designed by the British Motor Corporation's (BMC) Competition Works Department. "AMR's approach to the design and manufacture of ultra-fidelity products that challenge the status quo is, we feel, not that dissimilar from BMC taking the contrarian Mini motor car and turning it into an all-conquering rally car which punched well beyond its unassuming exterior. Hence, the name Abbingdon Music Research was arrived at in deference to the birthplace of the compact but prodigious Mini rally car."

On thoughtful details, the backlit remote includes a movement sensor to activate the display when picked up. While this is too faint to be seen during the day where you don't need it, this feature it quite da bomb at night. Wowza.

In fact, except for the RCA digital input which AMR finds inferior to USB, I can't think of a single feature in this massive one-box CD player that's been forgotten or -- deciding on our behalf -- deliberately omitted. The only area of minor concern is the future when the valves need replacement. Safe for the adventurous and confident, a trip to the dealer might be in order to perform the operation of cracking into the chassis vault and getting at the innards. But according to AMR, this will be quite - futuristic. In short, valve life depends on how conservatively a tube is run; origin (the selected NOS units have a far longer rated life expectancy); and correct applied voltage regardless of mains supply (regulated in the CD-77 by OptiMains). Apparently as little as 5% over voltage from the mains supply reduces long-term usage of a tube by half. That's the short answer.

The longer one names heater voltage, cathode current and anode dissipation in particular. Explained Vince, "the EZ80 for example is rated for 90mA current under operation where it will exhibit around 10-watt anode dissipation. If used like this, the life span will be around 2,000 - 4,000 hours. The same goes for all valves. A Western Electric 300B is rated for 10,000 hours at 300V/60mA which is 18W or 45% dissipation and 60% rated cathode current. If you operate the WE 300B at 5.2V heater voltage, 400V anode voltage and 100mA cathode current (which is all well within specifications, even for simultaneous application), the valve will struggle to see 2,000 hours.

"All our gear runs the valves extremely conservative. The ECC81 in the CD-77 runs at around 10% dissipation and cathode current, the 5687 at around 40% of dissipation and cathode current ratings, the 5687 in the AM-77 at around 30% of cathode current and anode dissipation rating, the EZ80 at around 20% of rated cathode current anode dissipation. When derating devices including valves, the life span increases by more than the square of the derating. Thus small signal valves that normally operate 4,000 - 10,000 hours when exploited at the maximum ratings and less if overheated will last for very long periods if used conservatively.

The issue of valve live span is more an issue of implementation than of the actual valve. Most companies that produce tube equipment tend to operate the valves within an inch of their life and then some in an attempt to maximize the amount of power, gain, transconductance etc. they can obtain for a given investment. They let their customers pick up the tab for frequent tube replacements. For AMR products, we did not feel that such a cavalier attitude towards our customers and products was desirable. Hence we applied considerable effort and skill to maximize valve live. All the tubes we use are rated by their manufacturers at 10,000 hours under normal operating conditions. We operate them aggressively derated and far below those specified values."

USB and internal Redbook data both benefit from AMR's military-spec TXCO clock modules (the USB clock sports identical specs to the master clock but operates at a different frequency), purportedly exceeding the phase noise performance of even upscale after-market super clocks by a factor of at least 10. This clock distribution synchronizes all the clocks -- even the front panel display and microprocessor's control -- to the single master clock before the data is applied to the converter, to minimize jitter which can arise from cross-talk between multiple clocks, different clock frequencies and/or a lack of clock synchronization. For the same reason, the clock distribution circuit past the clock is below 1" in length to eliminate reflections and transmission line effects. In fact, the circuit traces carrying the clock signal are said to be shorter even than the cables which usually connect after-market super clocks to the main circuit board.

This circuit compaction, according to AMR, results in jitter performance that cannot be achieved by add-on clocks or dedicated separate clock generators which insert long clock cables and are open to ground loops, external interferences and other compromises. That's exactly why S/PDIF i/o ports were rejected. The S/PDIF interface isn't reclocked on the receiver side but must recover the clock from the source. This was deemed unacceptable, hence no S/PDIF digital inputs or outputs.

The 'digital engine' board beneath the transport, "generally speaking, includes a total of 10 separate, pre-regulated supply voltages with a further 10 local power supply regulators; made possible by taking advantage of the very latest chip designs; the most advanced active and passive surface mount (SMD) components and multi-layer circuit boards. This very compact layout, for all practical purposes, eliminates any issues of signal carrying traces showing transmission line behavior with distinct reflections which can increase jitter and equally minimizes, to an extreme extent, the amount of electromagnetic energy radiated. To this end, all ICs switching fast and at high clock speeds are fitted with small metallic shields over their chip and main parts of the lead-out frame.

"The following brief tour of this board is a more specific overview of what we consider to be 'unusual' techniques and components of the digital side of the CD-77: To the right side of the DAC, all the capacitors, resistors and three-legged chips are the various shunt regulators for the converter and critical digital circuitry (a total of 6 on that side). Next to that is the venerable TDA1541 DAC and its decoupling capacitors for the Dynamic Element Matching (a little-known circuit designed in by the boffins at Philips) and specially selected SMD film capacitors (not the garden-variety ceramic capacitors often used nor the large-size leaded capacitors found otherwise which have by far too much inductance to clean up the switching spikes from the TDA1541 DEEM circuit).

"In the top/center of the PCB are the various digital processing chips, including topmost next to the Master Clock generator (the right of the two) the clock distribution, then the Custom Logic including the OptiSample engine and the digital filter and reclocker with finally the two OptiSignal circuits next to the top/left side of the TDA1541 chip. The upper left-hand side handles the USB connection including its own clock (AMR TCXO I) and is only switched on if the USB input is in use. The lower left-hand side contains the servo and control circuit for the drive (the controlling microprocessor is on a separate board with its own independent power supply).

"Finally, the whole leftmost strip of components contains the two independent, discrete low noise power supplies that drive the Master Clock (AMR TCXO II) and the USB clock. Further extensive regulation circuits are off-board. In addition, notable are the very large number of both conventional and X2Y surface mount capacitors and Sanyo Os-Con capacitors very close to the various integrated circuits which decouple the power supply lines for all circuits and offer a near perfect resistive power supply impedance up to around 100MHz which will minimize digital noise across the full range."