Предусилители — Audionet STERN

The STERN is a stereo line preamplifier handmade in Berlin by Audionet, with a US price of USD 45,000, and its casework was designed by Hartmut Esslinger. It can stand upright or lie flat, and its colour TFT display, offered in a light or dark version, can be set for either orientation. Silver and black finishes are listed.

Key specs that matter

Frequency response reaches 0 to 2,200,000 Hz at -3 dB when DC coupled and 0.3 to 2,200,000 Hz in AC coupled mode. THD+N is below -116 dB at 1 kHz and below -104 dB at 20 kHz, while the signal-to-noise ratio tops 123 dB referenced to 4 V RMS. Channel separation is above 144 dB from 20 Hz to 20 kHz. Output impedance is 24 ohm real on RCA and 48 ohm real on XLR, with output current up to 60 mA. Standing vertically the unit measures 270 x 500 x 505 mm, or 450 x 320 x 505 mm when horizontal, and it weighs 38 kg. Typical consumption is 100 W, standby draw is under 0.5 W, and mains versions for 220-240 V or 110-120 V at 50-60 Hz exist.

Engineering and use context

Each channel gets its own transformer for the positive and the negative half wave, giving four encapsulated, decoupled 50 VA toroids bolted on stainless steel. Main reservoir capacitors of 22,000 uF use a silk dielectric, and total capacitance comes to 176,000 uF. Gain stages are discrete Audionet operational amplifier modules with mica capacitors, and the circuit is DC coupled with short signal paths in a double mono arrangement. Volume is handled electronically through a precision resistor network linearised in real time, operated by a knob with twin ball bearings, magnetic detents and optical sensing. Opto couplers isolate the analogue circuitry galvanically, the patented Floating Pane Design suspends the panels on an aluminium frame, and ferromagnetic materials were left out of the build. A power supply monitor oversees the microprocessor control.

Pairing

Sources connect through four rhodium-plated Furutech RCA input pairs plus two pairs of balanced Neutrik XLR sockets. The output panel carries two XLR pairs, two standard RCA pairs and a phase-inverted RCA pair, so more than one power amplifier can be driven. Two optical Audionet Link ports switch further Audionet devices, a by-pass mode supports home cinema use, and an extra earth terminal is fitted.

Alternatives

The Audionet PRE G2 is another preamplifier from the brand, which Audionet equips with mica parts, chosen high-voltage film capacitors and internal wiring made of silver and gold alloy.