SCHOEPS
GmbH · Spitalstr. 20 · D-76227 Karlsruhe (Durlach) · Tel: +49 721 943 20-0 · Fax: +49 721 943 2050
www.schoeps.de · [email protected]
Technical Specifications, Electromagnetic Compatibility
Microphone Amplifiers
Amplifier type
Powering
Current
Impedance
Low-cut
consumption
frequency (-3 dB)
CMC 6U / 6Uxt:
12 V phantom
8 mA
25 Ohms
20 Hz
48 V phantom
4 mA
35 Ohms
20 Hz
(automatic switchover)
CMC 5U:
48 V phantom
4 mA
35 Ohms
30 Hz
CMC 3U:
12 V phantom
11 mA
20 Ohms
30 Hz
CMC 4U:
12 V parallel
9 mA
13 Ohms
30 Hz
Polarity: Increasing sound pressure on the microphone's 0° axis produces a positive-going voltage
at pin 2.
Maximum output voltage:
1 V (at 1 kHz and 1 kOhm load resistance)
Minimum recommended load resistance: 600 Ohms (A load resistance below this value will par-
ticularly reduce the maximum output level.)
The other technical specifications depend on the choice of capsule – see page 12 ff.
Length:
116 mm (incl. 3 mm capsule thread)
Diameter:
20 mm
Weight:
65 – 68 g, depending on type
Surface finish: matte gray (g) or nickel (ni)
electromagnetic fields. This is particularly true
for CMC 6 amplifiers made since 2004; they
can be recognized by the gold-colored shield
plate in their output connector.
Due to the wide dynamic range of studio
microphones, the smallest signal amplitudes
are in the microvolt (1/1,000,000 Volt) range.
Cable shielding and the grounding scheme of
the preamp or mixer input are also crucial.
Thus no microphone can ever be immune to
all possible disturbances under all circumstances.
But the following suggestions can help to
reduce the likelihood of picking up noise:
1) Keep both the microphone and the cable
away from sources of interference such as
monitors, digital equipment (computers),
RF emitters (mobile phones), power trans-
formers, power lines, SCR dimmers, switch-
ing power supplies etc.
2) Use only high-quality cables with a high
degree of shield coverage.
3) Keep all cables as short as possible.
4) Dress audio cables away from power cables.
If they must cross, it should be at right angles.
5) At the preamp or mixer input, the shield of
the microphone cable should connect to
chassis ground in the shortest way possible.
If necessary, this coupling can be capacitive.
Simultaneous Connection to Multiple Inputs
If one microphone must be connected to mul-
tiple inputs simultaneously, an active micro phone
splitter should be used in order to preserve
the loading and powering conditions for the
microphone, and to prevent interference.
Maximum Cable Length
Cable lengths of several hundred meters are
possible; Colette Series microphones are some -
times used with cables as long as 500 m (over
1/4 mile!). But the practical limit depends on
the electrical capacitance of the cable, which
is sometimes an unknown quantity. The lower
this capacitance is per unit length, the longer
the cable can be. All
SCHOEPS
cables have
very low capacitance (100 pF/m between the
conductors).
The main risks with excessively long micro-
phone cables are losses at high frequencies
due to cable capacitance, reduced ability to
handle very high sound pressure levels, and
increased likelihood of picking up interference.
No tes on Electromagnetic Compatibility
SCHOEPS
CMC microphone amplifiers are
virtually immune to magnetic, electric and
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