Page 1
107 MM (4-7/32 IN.)
FIGURE 1
OVERALL DIMENSIONS
Phase: Gate Switch:
Corresponding pins of Input and Output connectors With the Gate
switch set to the OUT position, the
are in phase. gain
of the Voicegate remains constant at unity and
Impedances: the Gate lamp turns on. In the IN position, the Voice- gate performs its normal gain control function and the Input Designed for Use With Actual Impedance Gate lamp flashes intermittently.
Lo-Impedance Balanced or unbalanced 25 to 680 ohms f25% 600 ohm microphones balanced Power Switch and Pilot Light (M625): Hi-Impedance Unbalanced IOk to 50k ohm 130K ohms f 25% The Power On-Off switch controls the ac power microphones unbalanced applied to the M625 and the dc power supplied to all
Output Designed for Use With M625AM units connected to the M625. The pilot light Actual Impedance is illuminated when the ac power is connected to the LO-Impedance Balanced or unbalanced 25 to 600 150 ohms i15% M625 and the Power switch is in the ON position. ohm microphone level circuits unbalanced
Hi-Impedance Unbalanced IOk to 50k ohm 2k ohms 215% microphone level circuits unbalanced Microphone Input:
The microphone input is designed for low-impedance
Temperature Range: (balanced or unbalanced) microphones with 25 to 600
Operating:
-7OC to 57OC (20°F to 135OF) ohms impedance or high-impedance (unbalanced)
Storage:
-2g°C to 710C (-200F to 160°F) dynamic, ribbon, or condenser microphones. The unit
is not recommended for use with crvstal or ceramic
Weight:
M625: 1.93 kg (4 Ib, 4 oz) M625AM: 1.48 kg (3 Ib, 4 oz)
Dimensions:
See Figure 1
Operating Voltage and Power:
Ac Operation:
M625: 108-132 volts, 50/60 Hz, 3 watts
Dc Operation:
30 volts
&20%, 5.5 mA, and 9 volts +35%, 20 mA with Gate lamp illuminated (M625AM and M625).
CONTROLS AND CONNECTORS
Hold Time:
The Hold Time control sets the period of time that
the Voicegate maintains unity gain after the input
signal drops below the trigger level. At minimum (full
counterclockwise) position, it sets the hold period to
approximately
'/4 second; at maximum (full clockwise)
position the hold time is approximately 45 seconds.
Sensitivity:
The Sensitivity control sets the level at which the
input signal triggers the control circuit to increase the
Voicegate gain to unity. With a high-impedance input,
the trigger level may be varied from approximately -40
dBV (10 mV) with the Sensitivity control at 0 (fully
counterclockwise) to -74 dBV (200 pV) with the con-
trol set to 10. Corresponding levels for the low-im- pedance input are -62 dBV (790 pV) at 0 and -96 dBV (16 pV) at 10. The Sensitivity control is adjusted
by observing the Gate lamp. The Gate lamp will be
illuminated when the input signal is above the control
circuit trigger voltage as adjusted by the Sensitivity
control, and will turn off quickly when the signal drops
below this level. The Sensitivity control should be
adjusted so that the lamp is off when only background
noise is entering the microphone, and turns on reliably
when actual speech is present. microphones. The
microphone impedance is selected
by a slide switch above the Microphone lnput recepta-
cle on the rear panel. The input receptacle is a
professional three-pin audio connector (female).* See
Figure 2 for low- and high-impedance microphone
input plug connections.
NOTE: some condenser microphones produce very
high output signals which may overload the
input. Use of an attenuator (such as the Shure
A15A In-Line Low-Impedance Microphone At- tenuator) will improve this situation.
Microphone Level Output:
The microphone-level output is available at the re-
ceptacle labeled Mic. Level Output on the rear panel.
It is a dual-impedance output, either low-impedance or
high-impedance unbalanced, as selected by the switch
above the receptacle. The low-impedance output will
drive either a balanced or an unbalanced microphone
input.
SHIELD
1-,---- --,' MICROPHONE MIC. INPUT MICROPHONE MIC. INPUT
LOW IMPEDANCE HIGH IMPEDANCE (BALANCED LINE1
MICROPHONE INPUT PLUG CONNECTIONS
SHIELD -
2 MIC. OUTPUT MIC.
OUTPUT LOW IMPEDANCE HIGH OR LOW IMPEDANCE (BaANCED LINE) (UNBALANCED LINE ) MICROPHONE OUTPUT PLUG CONNECTIONS
INPUT AND OUTPUT CONNECTIONS - FIGURE 2
* Designed to mate with Cannon XL series, Switchcraft A3 (Q.G.) series or equivalent connector.
