Предусилители — Accuphase C-2300

The C-2300 is a precision stereo control center from Accuphase Laboratory in Japan, built around Balanced AAVA, described by Accuphase as the next step after its original AAVA volume control. The maker states that this balanced version lowers the noise level by about 10% compared with the C-2450, and the model also gains a newly added four-band tone control.

Key specs that matter

On the rear panel sit five unbalanced line inputs and two balanced XLR inputs, two unbalanced line outputs and one balanced output, recorder PLAY and REC jacks, and external preamplifier inputs in RCA and XLR form. Rated output is 2 V at 50 ohms, maximum output is 7.0 V, and the minimum load is 600 ohms. Frequency response runs from 3 Hz to 200 kHz within 3 dB, total harmonic distortion is 0.005% from 20 Hz to 20 kHz, and the S/N ratio is 111 dB with the input shorted and A-weighted. Balanced input impedance is 40 kilohms, unbalanced 20 kilohms, and crosstalk is 74 dB down at 10 kHz. Gain is 18 dB by default with 6 dB steps either way. The unit is 465 mm wide, 150 mm high and 405 mm deep, has a net mass of 19.3 kg and consumes 41 W with both option boards fitted.

Engineering and use context

Instead of a resistive potentiometer, whose contacts wear and add noise, the knob drives an in-house volume sensor machined from an aluminium block with a solid brass shaft 8 mm thick, and a motor turns it quietly when the remote is used. Each channel has its own Balanced AAVA board with five unit amplifiers, a transformer in its own case and two 10,000 uF custom filter capacitors. The tone section works at 40 or 125 Hz, 500 Hz, 2 kHz and 8 or 20 kHz. An output selector chooses all, line, balanced or none, and a recorder selector offers off, on and play. The headphone amplifier is a discrete design with parallel push-pull output stages, and the case rests on high-carbon cast iron insulators. A loudness compensator, a 20 dB attenuator, per-input phase memory and mono switching complete the controls, and the 230 V version switches itself off after 120 minutes idle.

Pairing

Two option slots accept the AD-60 phono board, with 40 dB MM gain at 47 kilohms and 66 dB MC gain with 30, 100, 200 or 300 ohm loading plus a 25 Hz subsonic filter, and the DAC-60 board with two ESS ES9016K2M chips in parallel, taking USB DSD up to 11.2 MHz and PCM up to 384 kHz. The supplied RC-250 remote also operates Accuphase CD players.

Alternatives

The Accuphase C-2450 is the other stereo preamplifier from the brand that the maker uses as its reference point when quoting the lower noise of the C-2300.