Mastering   -   Opal class

orchestra in studio

Design philosophy

Opal class mastering systems are the reference for defining transparency and seamless-integration across the various platforms of music reproduction, as described in the Application Standards.

Lenard designs are available through Open-source license to those wishing to market these designs.



Opals are large-scale, fully-integrated 4-way active sound-systems, designed to replicate the fidelity and dynamic-energy of real orchestras.   And at the zenith of a bell-curve where performance diminishes by being smaller or larger.

opal speaker system

Opal class are designed for applications where the highest standards of performance are required, Studios, Cinemas, jazz club PAs and homes.


Opal cabinets are adapted to suit various environments.   The bass-cabinets can be placed together or above and below the centre-cabinet to achieve the correct listening height.   The sub-bass speakers can be 15in, 18in or 21in.

Canberra Opal

The home Opal system occupies minimal space in the room.   The centre cabinet can be rotated so the compression-driver/horn is at optimal listening height.   The sub-bass speakers in the system above are 27in.


Lenard Valve Towers


Opal class systems are fully-integrated, inclusive with solid-state amplification.

Valve-towers are designed for audiophiles who are passionate about tube technology.   A valve-tower for each speaker-stack.   The design philosophy assumes an evolutionary process that would have occurred if solid-state technology had not existed.

Opal Red Gum

The tube amps are aligned vertically.   The lower amplifiers drive the bass-speakers.   The top tube amps drive the higher frequency speakers, the order is logical to follow.

Canberra Opal Valve Towers

Each 100 Watt amplifier is a separate module and can be easily exchanged.   Valve bias (temperature) is simple and safe to adjust.   The towers are initially calibrated for KT88s.   However many variation of power-tubes can be used.

The two red LEDs (light emitting diodes) beside each each power-tube are comparators.   When both LEDs are at the same light intensity, valve bias is at optimum.

The unique performance of valve amplifiers is a function of the output-stage (power-valves and output-transformer).   The driver circuitry is solid-state which is silent and non-microphonic.   Zero-noise driver circuitry is essential for active speaker systems that use high efficiency speakers and compression drivers.

Opal Valve Tower Electronics
Opal Valve Tower PCB

The design philosophy assumes an evolutionary process that would have occurred if solid-state technology had not existed.   A detailed technical explanation of tube-amps is in the Education section of this site.

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