Предусилители — Accustic Arts TUBE PREAMP V PHONO

Accustic Arts builds the TUBE PREAMP V PHONO by hand in Germany as a tube hybrid reference preamplifier delivered with an MM/MC phono section on board. Four reference tubes, two for each channel, sit in a circuit that stays fully balanced from the first input socket to the last output. Accustic Arts offers the same phono upgrade for both its tube and transistor preamplifiers of this generation, and the finishes shown are aluminium with chrome, black with chrome and black with gold.

Key specs that matter

For moving magnet cartridges, input capacitance is selectable from 50 to 425 pF in 25 pF steps. MC loading options are 47, 100, 220 or 470 ohm. Referenced to 775 mV with A-weighting, the phono noise figure is 84 dB for MM and 75 dB for MC, with THD+N of 0.007 percent and 0.04 percent. The line stage has a noise figure of 103 dB A-weighted or 95 dB unweighted, keeps THD+N under 0.0015 percent and holds crosstalk above 99 dB. Bandwidth extends from DC to 50 kHz at -0.5 dB and to 120 kHz at -1.5 dB, and up to 18 V can be delivered. Line inputs have 50 kohm impedance, outputs 50 ohm. The unit is 128 x 482 x 393 mm and weighs 16.0 kg.

Engineering and use context

Accustic Arts calls its tube section plug and play, because the valves can be exchanged without any recalibration. The signal then passes a Class A output stage using Burr Brown OPA 627 op-amps. Two magnetically shielded 50 VA toroidal transformers supply the circuit, relays with gold-plated contacts select sources, and a four-channel digital volume control tracks both halves of each balanced channel. Balance between channels stays within 0.2 dB over the first 60 dB of attenuation. The rear panel carries three XLR and two RCA line inputs plus an RCA surround bypass, twin XLR and twin RCA line-outs in AC-coupled and DC-coupled versions, a fixed RCA feed, an unbalanced XLR output and a 6.3 mm headphone jack. A polarity switch offers 0 or 180 degrees. Power draw is roughly 20 W running and below 0.5 W in standby.

Pairing

The capacitance range lets the stage be matched to MM cartridges that specify a particular load, and the four MC settings cover low output coils with differing internal impedance. Since phono and line switching share one chassis, a turntable and digital sources run into a single unit ahead of the power amplifier, and two outputs for an external headphone amplifier are provided.

Alternatives

The line-only TUBE PREAMP V from Accustic Arts shares this tube hybrid circuit but comes without the phono board.