Фонокорректоры — Pro-Ject Tube Box DS3 B

The Tube Box DS3 B is a dual mono phono stage built around valves by Pro-Ject Audio Systems, and it is the first model of the long running Tube Box family to add balanced inputs and outputs. Its circuit comes from Dr. Sykora, the unit is handmade in Europe, and it is produced in silver and black versions. Two record players may stay plugged in simultaneously, and the front panel gives access to every setting, with separate values remembered for each input.

Key specs that matter

Amplification relies on a pair of E88CC valves, also known as 6922. Six gain steps are available - 40, 45, 50, 55, 60 and 65 dB - and the XLR outputs add a further 6 dB. Loading is stepless from 10 to 1,000 ohm or fixed at 47 kohm, while the capacitance options are 50, 150, 300 or 400 pF. With 5 mV at 1 kHz and the 40 dB setting the output reaches 500 mV. Pro-Ject quotes more than 87 dBV signal to noise A-weighted, THD below 0.03 percent and RIAA accuracy of plus or minus 0.5 dB from 20 Hz to 20 kHz. A subsonic filter acts at 20 Hz with an 18 dB per octave slope. Inputs are a 5-pin mini XLR socket, one pair of XLR and one pair of RCA, and outputs come as RCA and XLR pairs. The 18 V, 1,000 mA DC supply feeds a draw of up to 750 mA, with less than 0.5 W in standby. The case is 206 x 70 x 194 mm and weighs 1.56 kg, adapter excluded.

Engineering and use context

A balanced link carries each channel as a hot and a cold signal holding the same programme, so the stage can extract the music and reject noise that both legs collect along the way from household wiring and appliances. The 5-pin mini XLR input accepts a single cable straight from a turntable arm that uses this connector. Impedance is adjusted by a potentiometer, a Pro-Ject method that allows the load to be turned while a record plays so the effect of each value is heard immediately. The E88CC valves were picked for low noise and low microphonics. Pro-Ject specifies polypropylene capacitors and audiophile-grade parts throughout, including the valve output stage.

Pairing

The wide gain range lets the level be matched to MM and MC cartridges with different output levels and set close to other sources such as CD players or streamers, so switching inputs on the amplifier does not bring a jump in volume. Balanced preamplifiers and amplifiers take the XLR outputs, while the RCA pair covers conventional inputs.

Alternatives

The Pro-Ject Tube Box S2 is a valve stage from the S2 line with two replaceable ECC83 tubes, a FET input and front panel gain switching for MM and MC cartridges.