Предусилители — Orpheus Lab H Two 33BD Opus II

The H Two 33BD Opus II is the stereo preamplifier in the Heritage Opus II series, made by Orpheus Lab in Switzerland. It is a dual monaural, fully balanced analogue design built with discrete components, and it ships with a separate power supply. The US price is USD 52,900.

Key specs that matter

Connections start with three XLR inputs rated at 94 kohm impedance and up to 18.4 V RMS, and three RCA inputs with 47 kohm and up to 9.2 V RMS. Outputs are tri-state, meaning each can be set as inactive, balanced or unbalanced, and output B works in either PREAMP or BYPASS mode. The frequency response runs from 5 Hz to 1.5 MHz within +0 and -0.1 dB. THD+N is below 0.00063 percent at 1 kHz into 600 ohm, and dynamic range is above 132 dB balanced and above 126 dB unbalanced. The preamplifier draws 60 W in use and under 1 W in standby. Without its supply, the unit measures 440 x 440 x 146 mm, and the weight including the supply is 50 kg.

Engineering and use context

Orpheus Lab describes the signal path as six levels. Source selection switches between balanced and unbalanced inputs, and a conditioner stage then brings every signal to the same reference level whatever the input mode. Gain can be set per input from -12.7 dB to +12.7 dB in 0.1 dB steps, with separate left and right adjustment. The volume control covers -127.5 dB to +6 dB in 0.5 dB steps, and balance spans 12.8 dB either side in 0.1 dB increments. The attenuator uses CRQL technology, short for Constant Resistive Quadrupoles with a Logarithmic distribution, made from metal-film resistors of 0.1 percent tolerance with no semiconductors in the signal path, and each volume change completes within 150 ns. The final output driver has a slew rate of 2000 V per microsecond so it can drive low impedance loads and long cables.

Pairing

The BYPASS mode on output B lets the preamplifier share power amplifiers with a home cinema processor, which then sets the level for film playback. Heritage monoblocks such as the H Three M800 Opus II take the balanced output, and the Heritage SACD player completes the source side with a balanced output of 4.8 V RMS and a USB input for PCM and DSD. The larger M1400 monoblock, rated at 700 W into 8 ohm and 2300 W into 2 ohm, is the choice for difficult 4 ohm or 2 ohm loudspeakers.

Alternatives

The Orpheus Lab A Two 22D is the discrete preamplifier of the Absolute line, which uses CRQL volume control technology derived from the Heritage range.