The Evolution of Pure Class A Control | Available at Trimira Audio
The Gryphon Helios Preamplifier is a high-end two-chassis line stage developed as the successor to the Gryphon Pandora, incorporating technologies derived from the company's flagship Commander platform.
The Helios separates its sensitive analogue circuitry from the dedicated PSU 5 Dual Mono Power Supply, while employing a fully discrete Pure Class A dual-mono topology, zero global negative feedback, ultra-low-noise JFET input circuitry, and an 85-step relay-controlled volume attenuator.
With optional DAC3 and PS3 expansion modules, the Helios can also form the central control component of a highly configurable reference two-channel system.
At Trimira Audio, we recommend the Helios for listeners seeking an exceptionally transparent, flexible preamplifier capable of partnering with high-current Gryphon power amplifiers and other reference amplification.
Key Features & Technological Innovations
Two-Chassis Architecture with PSU 5
The Helios separates the analogue preamplifier from its dedicated PSU 5 power supply.
This physical separation is designed to reduce the influence of power-supply circuitry and transformer fields on the sensitive line-stage electronics.
The PSU 5 incorporates a dual-mono power architecture with substantial energy storage.
Ultra-Low-Noise JFET Class A Input Stage
The Helios employs discrete Class A JFET input circuitry designed to provide low noise and linear signal handling.
PCB-mounted input sockets are used to keep signal paths short and minimise unnecessary internal wiring.
85-Step Relay Volume Attenuator
Volume control is provided through an 85-step microprocessor-controlled relay attenuator.
Precision resistors and low-capacitance switching components provide accurate channel tracking across the available volume range.
Zero Global Negative Feedback
The Helios operates without global negative feedback and provides an exceptionally wide specified bandwidth of:
0.1 Hz–1.5 MHz (-3 dB)
The architecture is designed to preserve transient response and phase behaviour across the audio band.
Modular DAC3 & PS3 Expansion
The rear panel provides expansion capability for Gryphon's optional digital and phono modules.
Compatible options include:
- DAC3 Digital Module
- PS3 Phono Module
This allows the Helios to evolve alongside the rest of the system.
4.3-Inch TFT Touchscreen
A 4.3-inch capacitive TFT touchscreen is integrated into a 4 mm-thick glass interface.
The display provides access to functions including:
- Volume
- Balance
- Level matching
- System settings
- Green Bias control
Green Bias Control
The Helios can communicate with compatible Gryphon power amplifiers through the Green Bias system.
This allows Class A amplifier bias settings to be managed from the preamplifier, helping coordinate operating conditions across the system.
Technical Specifications
| Specification |
Gryphon Helios Preamplifier + PSU 5 |
| Topology |
Pure Class A Dual-Mono Line Stage |
| Inputs |
3 × Balanced XLR / 2 × Single-Ended RCA |
| Outputs |
2 × Balanced XLR Main Out / 1 × RCA Main Out |
| Frequency Response (-3 dB) |
0.1 Hz–1.5 MHz |
| Gain |
+18.0 dB |
| THD + N |
0.003% @ 1 kHz, Balanced Output |
| Input Impedance |
25 kΩ Balanced / 12.5 kΩ Single-Ended |
| Output Impedance |
8 Ω |
| Maximum Output Level |
20.0 Vrms Balanced / 9.5 Vrms Single-Ended |
| PSU 5 Reservoir |
2 × 83,000 µF |
| Display |
4.3-inch TFT Capacitive Glass Touchscreen |
| Preamp Dimensions (W × D × H) |
475 × 387 × 173 mm |
| Preamp Weight |
13.9 kg |
| PSU 5 Dimensions (W × D × H) |
475 × 387 × 173 mm |
| PSU 5 Weight |
18.2 kg |
| Combined Weight |
32.1 kg |
Reference System Architecture
The Helios is designed to sit at the centre of a sophisticated analogue and digital two-channel system:
Digital / Analogue Sources → Gryphon Helios → Gryphon Power Amplifier → Reference Loudspeakers
With its balanced XLR outputs and high maximum output level, the Helios is particularly well suited to high-end balanced amplification.
The optional DAC3 and PS3 modules can further consolidate digital and vinyl sources within the preamplifier platform.
Source & Amplifier Matching
The Helios provides both balanced and single-ended connectivity, allowing integration with a broad range of source components and power amplifiers.
Trimira Audio can assist with:
- Gryphon power-amplifier matching
- DAC3 configuration
- PS3 phono-module selection
- Balanced XLR system design
- Gain-structure optimisation
- Interconnect selection
- Green Bias integration
- Complete reference system configuration
Two-Chassis Installation
The combined system weighs approximately 32.1 kg, with the audio chassis and PSU 5 housed separately.
The external power supply provides additional placement flexibility and can be positioned away from the sensitive analogue preamplifier circuitry.
Trimira Audio can advise on:
- Chassis positioning
- Cable routing
- Mains-power requirements
- Equipment-rack placement
- System grounding
- Thermal considerations
Consult with the High-End Audio Specialists at Trimira Audio
The Gryphon Helios combines Pure Class A dual-mono circuitry, zero global negative feedback, ultra-low-noise JFET input stages, an 85-step relay attenuator, two-chassis PSU 5 architecture, optional DAC3/PS3 expansion, and Green Bias control in a sophisticated reference line stage.
Trimira Audio can assist with complete Helios system integration, including source configuration, Gryphon amplifier matching, modular upgrades, balanced cabling, and final system optimisation.
Contact the Trimira Audio two-channel specialists in Brisbane to arrange a private Helios listening session or discuss a complete Gryphon reference system.
