Предусилители — Gryphon Audio Helios

The Helios is a Danish line preamplifier with true dual-mono architecture, created by Gryphon Audio Designs as the evolution of the earlier Gryphon Pandora and drawing on work done for the Gryphon Commander. It ships with a separate PSU 5 Dual Mono Power Supply Unit, so the system occupies two chassis of identical footprint.

Key specs that matter

Input impedance is 25 kOhm balanced and 12.5 kOhm single-ended, with an 8 ohm output impedance. Gain is +18 dB, with a bandwidth of 0.1 Hz to 1.5 MHz at -3 dB. THD+N is quoted at 0.003% at 1 kHz through the balanced output, measured over a 10 Hz to 30 kHz band. Maximum output reaches 20 Vrms balanced and 9.5 Vrms single-ended, and maximum input is 20 Vrms balanced and 10 Vrms single-ended. Standby draw is 0.5 W or less, idle draw is about 90 W with both optional modules fitted, and two IEC C14 inlets accept 110-120 V or 220-240 V mains. The preamplifier and the PSU 5 each measure 47.5 x 38.7 x 17.3 cm (W x D x H), and they weigh 13.9 kg and 18.2 kg.

Engineering and use context

Signal first meets an ultra-low-noise dual JFET Class A buffer in fully discrete balanced differential form, and the whole signal path runs without global negative feedback. Volume passes through an 85-step relay attenuator using precision resistors under microprocessor control. Two custom 65 VA toroidal transformers, one for each channel, supply a capacitor bank of 2 x 83,000 uF, and the digital section and each analogue channel get their own supply with local shunt regulation. Four-layer circuit boards carry copper traces up to 70 um thick, and polypropylene capacitors decouple the supply rails. Two blanking panels leave room for the optional DAC3 digital module and PS3 phono module. A 10.9 cm capacitive touchscreen behind a 4 mm glass window handles the menu, which covers balance of plus or minus 6 dB in 1 dB steps, an output level of Normal or -6 dB, MM/MC selection for the phono module and filter settings for the DAC. The hard-anodised aluminium chassis is CNC machined and stands on Gryphon-designed spikes.

Pairing

Green Bias setup in the menu allows control of compatible Gryphon Class A amplifiers, and the Hyperion power amplifier was presented alongside the Helios. Fixed-level AV inputs on XLR or RCA accept a surround processor, while a 12 V link and an infrared remote handle power and control.

Alternatives

The Gryphon Commander is the other current line preamplifier from the same Danish company and the design from which the Helios borrows several innovations.