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AM-777: Features

AMR’s unique OptiGain® circuit is an unorthodox approach to amplifier circuit design that enables the AMR range of pre-main amplifiers to preserve the magical spirit of the music signal. The AM-777 maintains this tradition: with OptiGain® which is comprised of two-stages: first is a Single Ended Triode (SET) valve-stage without any negative feedback. The second section is a pure-power buffer stage using bi-polar technology to amplify the current to drive mainstream speakers with aplomb.


The analogue section of the AM-777 utilises AMR’s OptiValve® analogue stage with zero negative feedback and the 6H1n-EB valve. This is a premium version for long life with improved mechanical construction.

With no operational amplifiers or solid-state devices, this is a major factor behind why the AM-777 sounds so organic and “valve-like” that it can be compared to the finest SET amplifiers.

OptiUSB® Input

AMR’s design team has developed a USB DAC solution and maximised its potential for digital audio playback. The AM-777 with its dedicated USB DAC, is able to receive a USB signal (via a PC/Mac) and its OptiBus® USB digital transfer solution to enable all music content (including WAV, AAC, WMA, MP3 etc.) stored on a PC to be played back directly without a conventional digital source, with signal integrity preserved to the highest level.


AMR’s OptiLevel® unlike mainstream volume controls, with minimal, highest-quality components, ensures the transparency and energy of the music signal passes through unhindered via a combination of our Single Ended Triode (SET) valve-stage with a software-driven volume control. In conjunction with OptiBus®, this is AMR’s solution to a single source with volume control but without the significant sonic degradation found in mainstream CD players that use analogue/digital volume controls.


OptiOperation® modes offer unrivalled functionality and flexibility. Whatever the requirements of the system, one or more AM-777s are more than capable of delivering what is needed at the optimum level of quality and can be seamlessly integrated into larger or home theatre setups.


OptiTrans® power supply transformers have been designed as dedicated audio transformers. The AM-777 boasts one 380VA torroidal transformer for the output stage and one 32VA EI custom transformer for the valve stage. Again, such attention to power supply duties yields sonic results when it comes to supplying the highest quality of undisturbed power supply for the audio architecture.


OptiChassis® is based upon the "ratio aureum" design principle. Based around an extruded aluminium chassis and a pure copper inner chassis base, this lavish implementation is the only way to achieve an unrivalled low resonance signature with optimised electrical and thermal properties.


OptiCool® offers exceptional cooling performance without the need for traditional, resonant heatsinks that resound like many tuning forks.

Unconventional, Bespoke Components

Underpinning the design behind each and every AMR component is the use of premium parts which were chosen after extensive evaluation, lengthy and comprehensive 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 many amplifiers that cost twice, even three times as much, do not use such dedicated components.

Information and specifications subject to change without notice.


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