Design Overview of Luminous Audio Technology
Arion Phono Preamplifier
The Luminous Audio Technology Arion Phono Preamplifier is the result of over 35
years exploring the boundaries of state-of-the-art audio technologies. The circuitry is an
assemblage of the best sounding building blocks available for audio circuit design,
meticulously identified through years of study, observation, research, prototyping and
listening. The creation of this preamp has more in common with the creation and voicing of
a fine musical instrument than a theory-derived amplification circuit. The purity and low
level detail retrieval it provides are groundbreaking and reflects its unique lineage.
Circuit Overview:
The Arion uses a two-stage design:

The input gain stage utilizes cascoded/paralleled JFET topology for extremely low
noise and outstanding low-level resolving capabilities.

The second stage uses a differential design optimized for the higher signal levels and
also performs the RIAA equalization.

While both stages employ JFET based servos, their sonic footprint is minimal due to
extensive matching of all semiconductors, used only to guarantee balanced DC
performance.

The power supplies are a unity gain based design typically used in laboratory based
power supplies. Transformers are hum bucking C-core designs with isolated
primary and secondary windings for line noise rejection. Separate transformers are
used for the +/- supplies.
The circuit components include:
 1% metal film resistors and polypropylene film capacitors; all equalization
components are screened for tight tolerances, providing exceptional signal purity
and accurate RIAA tracking.

The electrolytic capacitors are high frequency and high temperature rated to
maximize circuit stability and provide long term reliability.

Active devices include Toshiba JFETS, low-noise small signal transistors and Sanyo
power transistors, all graded and matched.

Signal path connections are made with silver solder to enhance sonic purity.
Design Execution and Layout
The circuit layout is a work of art that takes into consideration all of the complicated
current loops and loads to control interactions between stages and minimizing unintended
feedback as the signal is processed by the gain stages and power supplies.
The supply and grounding networks benefit from many years of research into the best
implementation for lowest noise and maximum circuit stability. Additional performance
benefits are attributed aspect of the design, not realized in past competing designs.
The sonic effect of the PCB base material is controlled through minimizing the contact
footprint of all critical nets. The layout implementation provides excellent performance
without necessitating the use of exotic laminates or circuit compensation.
The advantages of designing with a four layer PCB is taken to its limits, with each stage of
the circuitry laid out with meticulous attention to the electrical demands of the circuitry.
Through careful consideration of the circuit biasing loops, signal return currents, and RFI
return paths, the layout plays an impressive role in allowing the circuitry to perform with
minimal interaction between the signal and the return current artifacts.
The operating points of the active devices have been fine tuned for their electrical “sweet
spots” and individually fine-tuned by ear.
Sonically the Arion presents a sense of purity, low level detail resolution and an absence of
ambient texture; it is highly musical and almost spooky in its ability to convey subtle
interactions and details that make your music sound genuine and involving.
Single-ended Design
Though balanced circuitry is a common approach to many serious phono stage designs, the
signal provided by the cartridge is not balanced. Therefore, we consider successfully
referencing the signal to the reference ground to be the correct approach. Being successful
requires maximum care in the layout and execution of the grounding circuit, which is an
area of our expertise that we have thoroughly studied and researched.
Balanced circuitry requires producing a pseudo ground for the cartridge output and
sending it through two duplicate gain circuits, matched signal paths and EQ circuits to
create the balanced output.
The Arion is a unique combination of engineering, experimentation and craftsmanship that
is guided by ear, nature’s perfect instrument, to protect the integrity and magic of your
music.
Michael Bettinger July, 2014