Интегральные усилители — Octave Audio V 110 SE

Octave Audio, based in Karlsbad in Germany, describes the V 110 SE as the first model in the Octave range to offer damping factor tuning. Its push-pull pentode output stage runs four KT 120 valves as standard and can be fitted with a phono board, so it can serve as an integrated amplifier with phono.

Key specs that matter

In the High position of its power selector it delivers 2 x 110 W RMS into 4 ohm and 2 x 130 W peak. On Low the figures fall to 2 x 70 W RMS and 2 x 90 W peak, and into 8 ohm output is 20 percent lower. Frequency response is 20 Hz to 70 kHz at 90 W within -1 and -3 dB, and 5 Hz to 70 kHz at 10 W within 0 and -2 dB. Distortion is 0.1 percent at 10 W into 4 ohm, signal to noise ratio is -100 dB at 90 W, and output noise stays below 200 uV. Input impedance is 50 kohm on RCA and 25 kohm on XLR with a sensitivity of 270 mV. The chassis measures 451 x 175 x 415 mm and weighs 22.3 kg. Consumption is 500 W at full power, 190 W idle and 20 W in Ecomode.

Engineering and use context

Damping factor is set by swapping the input driver valve. An ECC 82 gives the LOW setting with a factor of 5 and 34 dB gain, the factory ECC 81 gives MED at 7.2 and 37 dB, and an ECC 83 gives HIGH at 10 and 38 dB. Octave supplies the extra valves with the amplifier. LOW is intended for high efficiency and full range speakers, MED for normal dynamic designs. The power selector allows KT 150, KT 88 and 6550 valves, and a bias display with LEDs lets the owner check idle current, 28 mA on BIAS Low and 34 mA on BIAS High. Wideband output transformers use a silicon steel PMX core, and Octave states that the circuit remains stable when unloaded or short-circuited. The grid 2 voltage is 340 V, and negative grid voltage is set separately for each valve between -16 and -45 V with three turn precision regulators. Start-up takes 50 seconds with inrush current limited.

Pairing

Inputs comprise six RCA sockets, including a bypass input for home theatre, and one XLR. Any RCA input can be assigned to the optional MM or MC phono board, whose MM stage has 47 kohm impedance and 4 mV sensitivity, while the MC stage has 150 ohm and 0.5 mV. Signal to noise is 85 dB for MM and 73 dB for MC, and a subsonic filter cuts at 20 Hz with 12 dB per octave. Crosstalk between inputs is -105 dB and channel separation is 55 dB. Outputs include a regulated preamplifier output with 5 V RMS maximum, an RCA record output and one set of speaker terminals, and Octave specifies loads of 3 to 16 ohm with efficiency above 83 dB. Optional external capacitor units, called Black Box and Super Black Box, add supply capacitance.

Alternatives

The Octave V 80 SE is another push-pull pentode integrated amplifier in the V range, adding a headphone output.