Gryphon Helios Preamplifier without a power supply

The power supply shown is not included and can be purchased separately.

The Gryphon Helios marks a new level of audiophile precision. Building upon the developments of the Gryphon Pandora and technological advancements from the Gryphon Commander, it combines decades of engineering expertise in an uncompromising dual-mono design. For listeners seeking the highest musical purity and maximum system flexibility, the Helios sets new standards – both sonically and technically.

Design & Construction

The solidly constructed housing, made of extruded and CNC-milled aluminum, follows Gryphon's signature "Nordic Noir" design language. The characteristic waterfall-style front panel creates a striking visual signature. Combined with the separately available PSU 5 power supply, it produces a harmonious overall appearance, further accentuated by the iconic inverted triangle.

The design follows a true dual-mono configuration, in which each channel is completely separate. Resonance-controlled material thicknesses, hard-anodized surfaces, and Gryphon's proprietary feet optimize mechanical stability and energy dissipation. The result is a tightly controlled operating environment for the sensitive amplifier stages.

Signal routing & amplifier topology

At the heart of the Helios is an advanced Class-A input topology with exceptionally low-noise dual JFETs. The fully symmetrical, dual-differential signal path – consistently without global negative feedback – preserves the natural energy and detail of the music.

A precise, microprocessor-controlled 85-step relay attenuator handles volume control. Precision resistors and relays with minimal capacitance ensure linear, reproducible settings and exact channel balance. Four-layer circuit boards with up to 70 µm copper, PCB-mounted connectors, and extremely short signal paths confirm the uncompromising technical standards.

Power supply & power reserve

The power supply is based on two custom-built 65VA toroidal transformers – one for each channel. This is complemented by a massively sized capacitor bank and extremely low-noise regulated voltages for the amplifier stages, including local shunt regulators.
Additionally, the external PSU 5 power supply enables optimal spatial and electrical separation of the signal and supply sections.

The result is an absolutely black background against which even the finest sonic details effortlessly emerge.

Modularity & connectivity

The Helios is compatible with Gryphon's current modular platform. Two rear slots allow for the addition of the DAC3 digital module and/or the PS3 phono module. This allows the preamplifier to be flexibly adapted to individual requirements both at the time of purchase and later on.

Three balanced XLR inputs, two XLR outputs, two high-quality RCA inputs, and one unbalanced main output offer versatile integration options in demanding systems. A fixed AV level can also be set.

Operation & User Interface

The Gryphon Helios is controlled via a 4.3-inch capacitive TFT display embedded under a 4 mm thick glass panel. The menu navigation allows, among other things, adjustment of the start and maximum levels, balance, source sensitivity, display brightness, and the setting of a fixed AV level.

The integrated Green Bias control allows the Helios to communicate with compatible Gryphon power amplifiers. Firmware updates are conveniently performed via the rear USB port.

Features

• Electronics design by Tom Møller
• True dual-mono configuration
• No global negative feedback
• Microprocessor-controlled 85-step relay attenuator
• Ultra-fast discrete Class-A input buffer
• Symmetrical, dual-differential Class-A line stage
• Four-layer printed circuit boards, up to 70 µm copper
• PCB-mounted sockets for short signal paths
• Two custom-made 65VA toroidal transformers
• 2 × 83,000 µF capacitance, channel-separated
• Polypropylene capacitors for local decoupling
• Separate power supplies for digital and analog sections
• Extremely low-noise, regulated voltage design
• Local shunt regulators for noise reduction
• PSU 5 with additional DC outputs
• Optional DAC3 module (USB, 2× S/PDIF, AES/EBU, TOSLINK)
• Gold-plated Neutrik XLR inputs and outputs
• Gold-plated Gryphon RCA jacks with Teflon insulation
• Fixed AV level inputs
• Adjustable channel balance, start/maximum level
• IR remote control
• 12V trigger in/out
• Green-bias control for Gryphon power amplifiers
• 4.3" TFT touchscreen under 4 mm glass
• Firmware update via USB stick
• Separate housings for power supply and amplifier unit
• Standby power consumption = 0.5 W
• Design and manufacturing in Denmark

Technical data

• Input impedance (symmetrical): 25 kΩ
• Input impedance (asymmetrical): 12.5 kΩ
• Output impedance: 8 Ω
• Bandwidth (-3 dB): 0.1 Hz – 1.5 MHz
• Gain: +18 dB
• THD+N: 0.003% @ 1 kHz, BW 10 Hz - 30 kHz (balanced)
• Maximum output level (balanced): 20 Vrms
• Maximum output level (unbalanced): 9.5 Vrms
• Maximum input level (balanced): 20 Vrms
• Maximum input level (unbalanced): 10 Vrms
• Power consumption: = 0.5 W (standby), approx. 90 W (idle, incl. modules)
• Mains voltage: 110–120 V or 220–240 V
• Power connections: 2× IEC C14
• Display: 4.3" capacitive TFT under 4 mm glass
• Dimensions of Helios: 47.5 × 38.7 × 17.3 cm, 13.9 kg
• Dimensions PSU 5: 47.5 × 38.7 × 17.3 cm, 18.2 kg
• Shipping: Two boxes, each 58 × 57 × 28 cm