Phono preamplifier C-C-C50-MC-BA

MC (Moving Coil) cartridges have the advantage of a lower moving mass compared to MM (Moving Magnet) systems, but they also have the disadvantage of producing about 20dB lower output voltage, making low-noise signal amplification a real challenge. With a low-impedance MC system, it is not the current noise of the amplifier input stage that is critical, but the voltage noise, and a higher gain factor is required, which makes a bipolar input stage preferable. Therefore, we offer two completely separate phono preamplifiers for MM and MC systems. Designs that are switchable between the two systems generally cannot handle either system exceptionally well.

The first linear amplifier of the MC version is also a discrete OTA, but its input stage uses the bipolar precision dual transistor SSM2212 instead of field-effect transistors as in the MM version. Due to the higher transconductance, the OTA achieves a signal gain of 40dB with minimal noise, while local current feedback preserves the perfect transient response, keeping nonlinear distortions below 0.0004% at 1mV input voltage!

The second and third linear amplifiers, as well as the passive RIAA equalization network, are identical to those in the MM version. However, unlike MM systems, where input capacitance needs to be adjusted, the input resistance must be adjusted to match the respective MC system. This can be set in 16 steps from 110Ω to 1kΩ via miniature rotary switches.

The total gain of the C-C-C50-MC-BA is adjustable in three steps of 5dB each, providing absolute gain (relative to 1kHz) of 55dB / 60dB / 65dB. As with the MM version, the sound quality can be described as: "As if there were (almost) only a cable in between!"

For turntables with externally routed connection cables, the C-C-C50-MC-BA is also available with RCA input jacks and shorter output cables as an alternative.