Professional Microphones
Bob Eaton
Senior Microphone Engineer
Made with pride in Conneaut,
Ohio U.S.A.
Description
The Equitek
E-350
from Conneaut Audio Devices is a multi-pattern side address microphone designed for professional
recording and broadcast applications. The implementation of high speed, low noise, low distortion electronics makes
the Equitek
E-350
the ideal candidate for the most critical applications.
The Equitek
E-350
incorporates a number of unique features including:
Large 1.1" Dual Diaphragm External Bias Condenser Capsule.
Gold Sputtered Diaphragms.
Servoed head amplifiers.
High SPL Capability (148 dB SPL with pad)
Transformerless balanced output circuits.
Internal power reservoir system that can supply ten times the current available from phantom powering
alone.
Remote operation without phantom power using internal batteries.
20 dB non capacitive pad
Stainless steel internal pop/EMI filter.
1 = Microphone Power On
0 = Microphone Power Off (Use this switch
position for fastest charging of batter-
ies.)
Power
Pattern
= Omnidirectional Pattern
= Cardioid Pattern
= Figure 8 Pattern
Pad
Hi-Pass
Left position = Low end roll off below 80 Hz.
Right Position = Flat low end response.
0dB = Full gain (Highest Sensitivity)
-20dB = 20dB Gain reduction (Highest
Clipping Level)
Switch Functions
Caution!
The high gain and wide bandwidth of the
E-350
microphone will easily overload the inputs of many professional mixing
consoles if adequate precautions are not taken. This is especially true if the microphone is going to be used on percussion
or amplified electronic instruments. If you have never used this microphone before, we strongly recommend that you
initially reduce the system gain by doing one or more of the following:
Enable the pad switch on the input of your mixing console.
Start with the input trim control on your mixing console turned down to a low level.
Enable the -20 dB pad switch on the
E-350
microphone.
Getting Started
The
E-350
requires 48 volt phantom power and the internal batteries must be charged for proper operation. Although
the internal batteries were charged at the factory, the batteries will gradually self-discharge if the microphone has been
in storage for a long time. It may be necessary to charge the batteries before initial use. Please see the section below on
powering the Equitek
E-350
.
Powering the Equitek E-350
The Equitek
E-350
is powered by a combination of 48 Volt phantom power and a pair of rechargeable 9 volt batteries.
This powering arrangement overcomes the inherent current limiting associated with most phantom power supplies.
The batteries are trickle charged by the phantom supply. When needed, the batteries provide the extra current necessary
during high SPL transients. The microphone will not function properly without the batteries present. The microphone
can be used without phantom power for periods of up to 6 hours provided the batteries are fully charged. Standard 9 volt
alkaline batteries can also be used if extended operation is needed when no phantom power is available.* (Auto power
shut off circuit must be disabled for battery operation without phantom power.) The minimum requirement for the
phantom supply is a regulated 48 volts with the capability of supplying at least 8 mA. of current. Supplies that do not
meet this requirement will not allow continuous operation of the microphone. Before initial use, the batteries may need
to be fully charged. Once the batteries have received this initial charge, they should not need to be charged in this manner
again, unless the microphone is unused for a long time. The batteries can be charged by two different means:
Connect the microphone to a phantom supply and allow the batteries to charge 12 - 14 hours with the mic
turned off.
Remove the batteries from the microphone and charge using a standard battery charger.
* See the section on Auto Power Shut Off. IF USING ALKALINE 9 VOLT BATTERIES, DO NOT APPLY PHANTOM
POWER TO THE MICROPHONE! DOING SO COULD CAUSE PERMANENT DAMAGE TO THE MICROPHONE
AND VOID YOUR WARRANTY!
NOTE: If you normally operate the microphone from phantom power, it is best to leave the microphone power switch
in the on or 1 position at all times. (The microphone automatically shuts off to conserve battery power when
phantom power is removed.)
Equitek E-350
Auto Power Shut Off Configuration
The Equitek
E-350
incorporates a circuit which shuts the microphone off if phantom power is removed. This is done
so that battery power will be conserved if the user forgets to turn the microphone off. If it is desired to operate the
microphone using only the batteries, this feature must be disabled or the microphone will not function. This is easily
done by means of a small movable configuration jumper located inside the microphone. To gain access to the inside of
the microphone, remove the XLR end cap by first removing the two screws. Then, loosen the screw on the back of the
microphone and slide off the microphone housing. The jumper is labeled JP1 and is located next to the battery holder
on the side of the card opposite the XLR connector. The jumper shorts two of three available pins to select the proper mode. From
the factory, the two pins towards the A are shorted to enable the auto shut off circuit. Two
disable the circuit, pull off the jumper and replace it so that the two pins towards the M (For
manual mode) are shorted. The microphone can be used with phantom power when it is in this
mode, however you must remember to turn the microphone off when not in use or the batteries will
be depleted.
The Equitek E-350 combines a
vintage capsule design with ad-
vanced electronics. Typical FET
(field effect transistor) condenser
microphones use discrete de-
signs. This means they use indi-
vidual transistors that must be
carefully matched for proper
characteristics. Even with care-
ful matching, discrete designs are
inherently nonlinear. Equitek mi-
crophones use a different ap-
proach. We do not use any dis-
crete FETs. Instead, we use ad-
vanced high speed OpAmps (Op-
erational Amplifiers). These
OpAmps are individually laser
trimmed for optimum perfor-
mance and have very high gain.
This allows a large amount of
negative feedback to be used to
significantly reduce any non-lin-
earity. During transients, these
OpAmps may require more cur-
rent than typical phantom power
supplies can deliver. The extra
current demands are accommo-
dated by our unique power sup-
ply design. Instead of using phan-
tom power to operate the micro-
phone, we use it to charge a pair
of rechargeable batteries. This
system creates a huge current re-
serve for the microphone's elec-
tronics, yet there is no mainte-
nance involved because the mi-
crophone automatically keeps the
batteries charged during use. The
use of OpAmps is not the only
unique feature of Equitek micro-
phones. For example, we also em-
ploy servo circuitry to minimize
dc offset and eliminate interstage
coupling capacitors. The bottom
line is we believe you will find
the Equitek E-350 to have a re-
markably open and clean sound
that will enhance any project.
All manuals and user guides at all-guides.com
