Josephson C716 User manual

JOSEPHSON ENGINEERING, Inc.
329A Ingalls Street, Santa Cruz, California 95060
Tel [phone] Fax [phone]
email [email protected]
http://www.josephson.com
©2011 Josephson Engineering, Inc.
MADE IN USA

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The Josephson C716 is part of the Series Seven range
of large diaphragm side-address microphones. It uses
large dual-diaphragm capsule similar to the one used
in the C700 microphones, with a fixed cardioid
directional pattern.
A unique feature of the C716 is its patented open-cell
metal foam grille. Unlike traditional microphone
housings made of perforated metal or wire screen with
reflective metal support structures, this highly open
material protects the capsule mechanically, provides
electrical shielding and some pop and wind screening
without needing any additional support structure. A
fine, acoustically transparent screen inside the grille
helps protect the capsule from breath moisture when
the C716 is used as a vocal mic. We were able to
avoid using a traditional basket support structure
because the foam itself is a tough self-supporting
aluminum alloy. It’s a highly open structure so that
internal reflections are negligible, while the metal still
provides full protection for the capsule. Traditional
designs incorporate rings and bars to support the
basket material, leading to the reflections shown in
the left illustration on the next page.

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These reflections in turn introduce acoustic resonances
in the microphone response which contribute to
frequency response and phase anomalies (which can
lead to harshness and other unpleasant sounds in the
pickup). Maintaining acoustical transparency around
the capsule is important in achieving the sonic clarity
that is this mic’s signature.
Using the C716
The C716 is a fixed cardioid-only microphone suited
for most studio pickup applications where a highly
detailed sound image is desired, with effective
rejection of unwanted sound off-axis. The dynamic
range is about 120 dB, sufficient to capture sounds
from the softest studio background to the loudest
percussion or amplified instrument.
Pickup is uniform over the entire front side of the
microphone, with no hot spots or dead zones that are
sometimes created by large-diaphragm microphones
having conventional basket grilles. Sensitivity drops 6
dB at 90 and 270 degrees, and then to a sharp null at
the rear of the microphone. It’s often effective to point
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Josephson Engineering, Inc. certifies that the C716 microphone
conforms to the applicable requirements of the European Union
directives as follows:
Machinery 93/68/EEC Exempt – passive sensor
Low Voltage 93/68/EEC Exempt – passive sensor
EMC 93/68/EEC Exempt – passive sensor
RoHS 2002/95/EEC Compliant for Hg, Cd,
Cr6, PBB, PBDE and Pb
Josephson Engineering, Inc., 329A Ingalls St., Santa Cruz CA 95060
Josephson microphones are warranted to be free of defects for five
years from the date of original purchase. If purchase documents are not
available, the warranty period begins when the microphone was
shipped from the factory. Josephson Engineering will, at its option,
repair or replace any microphone that fails, providing that it is returned
to the factory prepaid and has not been abused or altered.
There are no user-serviceable parts inside Josephson Engineering
microphones. Disassembling a Josephson microphone will void its
warranty.
For service information please contact Josephson at 831-420-0888.
Repair shipments may be sent to:
Josephson Engineering, Inc.
329A Ingalls St
Santa Cruz CA 95060
Certificate of Compliance
J
osephson Engineering, Inc.
Microphone Warranty

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C716 Specifications
Type: Electrostatic pressure/pressure-gradient
transducer
Marking: In accordance with IEC 61938
Rated power supply: Phantom 48 ±4 volts, 5 mA max.
in accordance with IEC 61938
Internal impedance: <80 ohms
Rated impedance: 200 ohms
Minimum load impedance: 1k ohms
Sensitivity: 26 mV/Pa (-32 dB ref 1V/Pa)
Frequency Range: 20-20,000 Hz
Directional characteristics: cardioid
Overload sound pressure: 134 dB SPL at 1000 Hz
Equivalent sound pressure due to inherent noise:
15 dB SPL, A-weighted rms in
accordance with IEC 60268-1
the rear of the microphone toward a specific unwanted
sound source, rather than trying to point the front
precisely at the desired sound.
The C716 incorporates a true dual diaphragm capsule.
Even though only the front diaphragm is electrically
active, the presence of the rear diaphragm produces
improved pop and plosive handling abilities compared
with similar single-diaphragm designs.
Vocal performers can use the microphone at any
distance from nearly touching the grille to many
meters away in the reverberant sound field. In addition
to the metal foam grille, a very fine internal screen
protects the capsule from breath sounds and moisture,
although an external pop screen may be needed in
some cases. Proximity effect yields flat frequency
response at about 75 cm (30”) with some low
frequency boost for closer sources, and low frequency
rolloff for more distant sources.
About the C716 Circuit
Like most Josephson microphones, the C716 uses an
all-discrete class-A circuit to transform the high
impedance of the capsule to a suitable level for
interface with mic preamps and consoles. A cascode
stage made of large-geometry field effect transistors
directly drives a pair of matched PNP bipolar
transistors in balanced emitter-follower configuration.
The emitter leads of the transistors are brought out
directly through a common-mode choke; the phantom
resistors in the powering equipment form the load
resistors of the mic circuit. The output impedance is
very low, and the output level can be quite high due to
the low loss nature of the circuit. High output level can
overload preamps and mixers when used close to loud

sound sources, so C716 users should take care to
monitor input levels to avoid clipping.
The internal power supply of the C716 uses a new
optically-isolated electrostatic circuit that provides
stable capsule polarization charge without the use of
oscillators or external power supplies.