Предусилители — Ayre Accoustics KX-8 Variable Gain

The KX-8 Variable Gain is a stereo line preamplifier from Ayre Acoustics, announced on 23 February 2024 with a base price of USD 6,400. It brings the true variable gain volume control of the company's KX-R preamplifier into a simpler and less costly chassis, and its modular rear panel lets the owner add digital inputs and a DAC. The unit belongs to the same 8 series as the VX-8 power amplifier and CX-8 CD player.

Key specs that matter

The standard analogue board carries two balanced XLR inputs and three single-ended RCA inputs, with one balanced and one single-ended main output. Rated output is 4 V RMS balanced and 2 V RMS single-ended, and the inputs accept up to 8 V RMS balanced or 4 V RMS unbalanced before overload. Input impedance is 1 megohm on RCA and 2 megohm on XLR, which works out to 1 megohm per phase. Frequency response extends from 0 Hz to 250 kHz. Front-panel headphone jacks come in both balanced and single-ended form. Consumption is 40 W in normal use and 60 W while the volume control is active. The case is 440 mm wide, 330 mm deep and 115 mm high, and weighs 5.7 kg.

Engineering and use context

Instead of throwing away signal in a resistive attenuator, Ayre's Continuously Variable Gain Transimpedance circuit, abbreviated CVGT, changes the gain of the amplifying stage itself to reach the level the system needs, which keeps the signal-to-noise ratio high at low volume. The whole circuit is fully balanced, discrete and free of feedback, and the outputs use the Ayre Diamond stage, which also powers the built-in headphone amplifier. A linear analogue supply feeds the electronics. Three factory options expand the digital side - a Roon Ready Ethernet streaming board at USD 1,000, a USB input at USD 800 and the X-8 DAC module at USD 1,300 with AES and coaxial or optical inputs. Fully equipped, the preamplifier offers up to eight digital inputs, namely Ethernet, USB, AES/EBU, two S/PDIF and three Toslink. The DAC is based on the ESS ES9038Q2M chip, runs to 384 kHz PCM and DSD512, and the network board streams Spotify, Qobuz and TIDAL. Two AyreLink RJ45 ports allow control of linked Ayre components.

Pairing

Balanced and single-ended outputs suit any power amplifier input, and the Ayre VX-8 links to it through AyreLink for joint power control. With the DAC module fitted, a CD transport or television can plug straight into the preamplifier without a separate converter.

Alternatives

The Ayre K-5xeMP is another preamplifier that Ayre lists next to the KX-8 in its range.