Classic Audio introduces MC PRO phono stage
Hand made in Kent, the MC PRO creates what the company claims is a: “pitch black background for serious vinyl listening. A hybrid input amplifier combining discrete bipolar input transistors with a servo-stabilised IC op-amp driver halves the input noise of the very best integrated circuits currently available for this critical point in the signal path.”
The company further explains that: “Conventional MM/MC combination phono stages degrade the MC noise floor by feeding a low gain MC head amplifier through the MM input, adding noise from both inputs. By amplifying the input signal by over 100 times in the first stage, as opposed to just 10 times for MM level in combination phono stages, the first stage’s output in the MC PRO is immunised against the noise of the next stage. This dedicated architecture permits a very quiet signal-to-noise ratio of 81dB against a 0.5mV input signal.
“Precise RIAA accuracy to within 0.1dB using telecoms-grade polystyrene film capacitors in a dedicated shunt feedback amplifier stage occurs straight after the hybrid head amplifier. Superior to the more common 0.5dB, it gives very low colouration and exceptional channel balance in the critical midband where the 500Hz and 2,112Hz RIAA turnover points lie. Unlike passive implementations, the active RIAA equalisation can handle 140 times the nominal level at 20kHz, so that overload never occurs in practice.
“Fully defeatable low-frequency crossfeed reduces vertical ‘vinyl roar’, uncovering new bass detail, particularly with headphones. As records must be mastered with bass frequencies centred, no information is lost by mixing bass frequencies to mono. A turnover point control on the front panel allows adjustment to taste. The worst surface disturbances inherent to the vinyl medium are attenuated 14 times at 10Hz by the 23Hz 3rd order subsonic filter, stopping them from destabilising and overloading amplifiers and loudspeakers, generating distortion.”
To extract maximum detail from mono pressings, a mono/stereo toggle switch is included on the front, bridging the two channels together when enabled. Distribution of gain in the triple-stage design yields less than 0.0005 percent distortion throughout the audio band, for a grain-free fully unveiled listening experience.
“The linear split power supply takes the power transformer and its troublesome magnetic fields out of the enclosure. Linear operation means no switching noise can make its way into the audio. The small external transformer also provides the best possible mains isolation. Splitting the internal power rails keeps non-linear amplifier power currents out of the ground path where they can generate distortion. A precise analogue comparator based start-up circuit keeps the relays closed for five seconds while the hybrid head stabilises, to prevent any thuds and bangs when switching on and off.”
Available to buy now for £650, you can find out more about the Classic Audio MC PRO here.
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