Фонокорректоры — Trafomatic Audio Evolution Phono One

The Evolution Phono One is a transistor-based phono stage made by Trafomatic Audio, the Serbian maker known mainly for valve electronics. Rather than tubes, its gain stages are built around OPA2134 operational amplifiers, with two of these chips fitted in each channel. The unit takes MM and MC cartridges on two separate pairs of inputs, and the load presented to a moving coil pickup is set by a switch on the front.

Key specs that matter

Gain is 40 dB on the moving magnet input and 64 dB on the moving coil input. The moving magnet input presents 47 kOhm in parallel with 200 pF, while the moving coil input offers four selectable loads of 10, 20, 50 and 100 ohm. Trafomatic rates noise and hum at 80 dB for the MM path and 76 dB for the MC path. Nominal output is 0.5 Vrms from a 600 ohm output impedance. RIAA accuracy is held within plus or minus 0.4 dB below 1 kHz and plus or minus 0.6 dB above 1 kHz. The chassis measures 450 x 320 x 100 mm and the unit weighs 6 kg.

Engineering and use context

A low-induction toroidal transformer inside the main case feeds the circuit, and the whole preamplifier is a single box with no external power unit. Two controls sit on the front panel - one chooses between the MM and MC inputs, the other sets the moving coil load among its four positions. On the rear panel a switch sets the mains voltage for the region where the unit is used, and a grounding lug accepts the earth wire from a tonearm cable. Signal leaves through single-ended RCA outputs, and both cartridge inputs also use RCA sockets. Keeping the MM and MC inputs apart means two turntables or two tonearms, one fitted with each cartridge type, can stay connected and be chosen with the selector instead of by swapping cables behind the rack. The operational amplifier circuit contains no valves, which means no tubes need replacing as the preamplifier ages.

Pairing

With its high coil gain and selectable loading, moving coil cartridges connect straight to the rear panel and need no separate step-up device. The output is a line-level signal, and the RCA outputs connect to an unbalanced line input of the following amplifier or preamplifier. Because there is no balanced output, the interconnect to the next component is an RCA cable in every system.

Alternatives

Trafomatic Audio also builds the Luna, a valve phono preamplifier in two chassis that uses passive LCR RIAA equalisation and transformer-coupled inputs and outputs.