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Analog Elemental Series
Preference Mic Pre | Technology
SSM 2019
The Preference Mic Pre is suitable for all common dynamic and condenser microphones. It
works along the principles of an instrumentation amplifier which is a technology that is also
used in measurement and medical equipment due to its high common mode rejection of stray
pick-ups. It is based on the semiconductor SSM 2019 which sounds more balanced than avail-
able alternatives. Low noise and distortion values as well as a broad bandwidth and a fast
slew rate are its forte.
Servo Drive Design
The main focus during the development of the Preference Mic Pre was its acoustic transpar-
ency and its natural representation of the source signal. Reducing DC offsets in the audio
signal paths is a decisive part of this design job.
DC offsets are produced in relatively large amounts especially when amplifying a microphone
signal because the signal is amplified by extreme factors from the pico volt range to 0dB
nominal level. DC offsets impair the signal quality as they induce noise and distortion that
lead to a diffuse sound.
The Preference Mic Pre‘s servo drive design minimizes these problems much more effectively
than the common solution based on capacitors by setting the DC offset to almost 0 mV. In
addition to that, the active servo drive circuitry tends to produce less distortions than passive
capacitors.
The servo drive design incorporates three operational amplifiers. The SSM 2019 is the first
op-amp. The second op-amp acts as a sensor to detect voltage differences. These differences
are then compensated for in a third op-amp working as summing stage.
Of course an elaborate active servo drive circuitry is a more expensive solution than simply
using passive capacitors, but especially in a microphone preamplifier this effort pays off with
improved sound quality.
Foil And Styroflex Capacitors
Only the best MKP and styroflex capacitors are used in the various circuits. They sound more
open and dynamic in contrast to the conventional ceramic capacitors.
Output
The output stage is electronically balanced and capable of driving very long cables (up to a
few hundred yards, depending on the capacity of the cables and the input stages on the other
end). The maximum output level is +22 dBu.