Фонокорректоры — Circle Labs Audio V1000

The V1000 is a valve MM and MC phono preamplifier made by Circle Labs Audio of Cracow, Poland, with its own step-up transformers for moving coils and a separate power supply. Its two inputs accept two tonearms or cartridges independently. The Circle Labs range also includes the A200 and AS100 integrated amplifiers, the P300 preamplifier and the M200 and M500 power amplifiers.

Key specs that matter

Gain is 65 or 70 dB for moving-coil and 45 dB for moving-magnet cartridges. Loading can be set from 10 to 1,000 ohm and capacitance from 0 to 320 pF, independently for each input. Outputs are RCA and balanced XLR. Equalisation offers turnover settings of 230, 318, 400 and 630 µs and roll-off settings of 100, 75, 50 and 25 µs, selected from the front panel, so RIAA, US and older pre-RIAA curves can be reproduced. The valve complement is four E88CC or 6922 double triodes. The phono stage measures 430 x 130 x 365 mm and weighs 9.5 kg, and the separate power supply measures 98 x 83 x 210 mm and weighs 2.8 kg.

Engineering and use context

Circle Labs winds its own step-up transformers. The primary uses 25-strand silk-braided litz wire and the secondary copper, with winding resistances of 0.25 ohm and 22 ohm to keep losses low. Stepping up the MC signal magnetically, before any valve, adds gain without the hiss of an extra active stage. The moving-magnet stage runs on ECC88 valves with fixed bias, and no negative feedback is used anywhere in the circuit. The design is fully dual mono. The power supply uses Mundorf polypropylene capacitors and a two-stage cascaded stabiliser without feedback, and placing the transformers in the separate box keeps their fields away from the phono circuits. Separate turnover and roll-off selectors allow records cut before RIAA standardisation to be played with the matching curve rather than an approximation. Front controls select MC, mute or MM and choose between the two arms or inputs.

Pairing

Circle Labs' own P300 preamplifier takes the XLR output, and any unbalanced line stage can use the RCA pair. With its wide range of loading and gain, the V1000 covers the load and gain needs of many MC designs, and two turntables or two arms can stay connected at once. The fuse is a T400mA type, and a 1.2 m mains cable is supplied.

Alternatives

The V1000 is the only model on the Circle Labs phono preamplifier page, so the maker has no other phono stage to suggest.