Предусилители — hARt Lab Tune Two

The Tune Two is a reference preamplifier from hARt Lab of Greece that builds a network streamer, digital converter, cartridge input and headphone output around a valve line stage. It is modular - the buyer can order it as a pure line-level unit and add the phono and DAC boards later. The UK price is GBP 16,500 including VAT.

Key specs that matter

Line gain is 21 dB and frequency response extends from 5 Hz to 120 kHz. There are four line inputs, rising to five when the phono module is not installed, plus coaxial and optical digital inputs and a media player that connects by Wi-Fi or Ethernet and reads files from three USB-A ports, one on the top panel and two at the rear. The optional FET phono stage offers 40 dB for MM and 66 dB for MC, with resistive loading of 47 kohm, 470, 220, 150, 100, 82, 70 or 60 ohm and capacitance of 100, 250, 330, 430 or 480 pF. Volume moves in 64 relay-switched steps of 1 dB. The unit stands 200 mm high, 430 mm wide and 390 mm deep with its cover, weighs 12 kg and draws 2 W in standby or 50 W at idle.

Engineering and use context

Amplification comes from a single Class A stage using one CV181 dual triode per channel, followed by a discrete FET tracking buffer that also runs in Class A. Two outputs reflect this layout - the main hybrid output passes through the buffer and tolerates loads above 16 ohm, while the direct output takes the signal from the tube stage alone and wants more than 30 kohm. The 6.35 mm headphone jack sits on the top surface and drives cans from 16 to 600 ohm through a hybrid circuit with a tube input and a transistor output. Digital conversion uses Texas Instruments SRC4392 and PCM5122 chips, and a single-board computer running Volumio handles bit-perfect or upsampled playback. Analog and digital sections have separate toroidal transformers, twelve local regulators stabilise the rails and the control circuits have their own supply. Inside the lacquered fibreboard enclosure is a damped metal chassis with Teflon valve sockets, Miflex KPCU-01 capacitors and Viablue wiring.

Pairing

The low-impedance hybrid output suits long cable runs to solid-state power amplifiers, while the direct tube output is intended for amplifiers with high input impedance. Everything is operated from a web browser on a phone, tablet or laptop. The side panels are interchangeable, and the front lighting offers 15 colours with three brightness levels or can be switched off.

Alternatives

The hARt Lab Tune Four is a more refined preamplifier from the same maker that keeps the streamer, DAC, phono stage and headphone output.