Предусилители — Ayre Accoustics KX-5 Twenty

Ayre Acoustics makes the KX-5 Twenty as a stereo line preamplifier within the company's Twenty series of electronics. It carries no phono stage or digital converter and concentrates on source switching and volume control, and every stage is discrete, balanced and free of feedback.

Key specs that matter

Six programmable inputs are provided, four of them XLR balanced and the remaining two RCA. Input impedance is 1 megohm unbalanced and 2 megohm balanced, and the maximum input level is 8 V RMS unbalanced and 16 V RMS balanced. Frequency response runs from DC to 250 kHz. Power consumption is 40 W at idle and 60 W while the volume control is being operated. The case is 438 mm wide, 337 mm deep and 95 mm high, and the preamplifier weighs 10.5 kg. On the XLR connectors pin 1 is ground, pin 2 is non-inverting and pin 3 is inverting.

Engineering and use context

Level adjustment relies on the Variable Gain Transimpedance circuit, which Ayre uses in place of a conventional attenuator by varying the gain of the amplifying stage directly. The control moves in 46 steps of 1.5 dB. A Diamond output stage of Ayre design feeds the outputs, and an EquiLock gain stage is used so that the circuit behaves the same way whatever source is selected. Input ground switching disconnects the ground of unused sources, isolating each component from the others. Power comes from a linear analog supply, and the Ayre Conditioner in the mains inlet reduces radio frequency interference from the power line. Its boards are made from a high-speed circuit material. Ayre fits the same VGT volume circuit and the same step count to the AX-5 Twenty integrated amplifier, which also shares its six-input layout. The controls, inputs and AyreLink sockets sit in a case whose width and height match those of the VX-R Twenty power amplifier. The AyreLink communication system lets the KX-5 Twenty send control commands to other Ayre components connected through the same link.

Pairing

Because the design is fully balanced, it is best matched to a power amplifier with XLR inputs, and Ayre's VX-5 Twenty and VX-R Twenty stereo amplifiers add AyreLink control so that the whole chain powers up together. On the input side, sources with balanced outputs can use all four XLR positions, while the two RCA inputs cover single-ended players.

Alternatives

The Ayre KX-R Twenty is the larger preamplifier in the range, with eight inputs, a 60-step volume control in 1 dB increments and an 18 kg chassis.