Предусилители — Octave Audio HP 700 SE

The HP 700 SE is a valve line preamplifier from Octave Audio of Germany, built on the company's modular platform with an outboard power supply. Its line stage uses Octave's Precision Technology, which the maker specifies with a bandwidth reaching 1 MHz and an output resistance as low as 100 ohms. The SE version adds two parallel XLR sockets next to the two RCA outputs.

Key specs that matter

Fixed inputs comprise three RCA and two balanced XLR, joined by two slots for freely selectable modular inputs and one RCA bypass input for a home theatre processor. Outputs are two RCA, one XLR and a monitor or tape record output on RCA. Gain can be set to 12 dB, 18 dB or 25 dB. Frequency response runs from 10 Hz to 200 kHz, with a deviation of -0.7 dB at high gain, -0.3 dB at medium and -0.2 dB at low. Distortion is 0.01 % at 3 V into 10 kOhm. Noise figures are -98 dB at high gain, -104 dB at medium and -110 dB at low. The main unit measures 462 x 130 x 480 mm and weighs 10.0 kg, and the power supply measures 110 x 90 x 277 mm and weighs 3.8 kg. Power consumption is 35 to 60 W, and a remote control, power cable and screwdriver are supplied.

Engineering and use context

One ECC82 (12AU7) and two EF800 pentodes make up the line stage, with EF184 listed as an alternative for the latter. Optional modules extend the design - a phono RIAA stage using ECC83, ECC81 and ECC88 valves with MM and MC input modules, including switchable step-up transformer versions, and a subsonic filter at 15 Hz, extra input modules, a frequency-compensated 47-position stepped attenuator with 0.1 dB channel deviation, which cannot be operated by the remote, and a control module with tone and balance controls that uses an ECC88. The outboard supply includes soft start electronics as part of the power management. Octave also lists selectable output impedance, so the output stage can be matched to the connected amplifier. In bypass mode for a multi-channel system the volume control is disabled and gain drops to 0 dB. The preamplifier is protection class 2, while the power supply is class 1. The finish is silver or black.

Pairing

The two parallel XLR sockets, together with the RCA outputs, can be activated separately or together, giving three output stages for separate rooms, different speakers, bi-amping or tri-amping. Octave's Jubilee 300 B and Jubilee Mono Ultimate monoblocks both accept RCA or XLR input and so fit either output type.

Alternatives

The Octave Jubilee Preamplifier is the preamplifier in the company's top Jubilee line.