dbx 363X User manual

MODEL 363X
aINoise Gate
Service Manual
(Preliminary)

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alerts you to the presence of uninsulated
dangerous voltage inside the enclosure —voltage
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alerts you to important operating
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Read the manual.
Manufactured under one or more of the following U.S. patents: 3,377,792; 3,681,618; 3,714,462; 3,789,143;
4,097,767; 4,329,598; 4,403,199; 4,409,500; 4,425,551; 4,473,795. Other patents pending.
This dbx-branded product has been manufactured by AKG Acoustics, Inc.
AKG is aregistered trademark of Akustiche u. Kino-Gerate Ges m.b.H., Austria.
All trademarks are property of their respective companies.
This manual is part number 96015-000-02
©Copyright 1993 by AKG Acoustics, Inc. 75 -FB -1/93
Jbx
dbx Professional Products
adivision of AKG Acoustics, Inc.
1525 Alvarado Street, San Leandro, CA 94577 USA
Telephone [phone] Fax: [phone]

Introduction
The half rack design of the 363X can accommo-
date up to four channels of gating in one rack
space, or 16 channels of gating in four rack spaces.
The 363X can be auseful tool in any musical
situation.
In the studio, the 363X can be used to:
•Eliminate headphone leakage into the mi-
crophones
•Gating drum mics to eliminate rattling
snares or to tighten the sound of akick
drum
•Gating instrument mics to eliminate amp
noise
•Muting the mixdown inputs to the two-
track as an economical solution to automat-
ion
In live sound applications, the 363X can be used
to gate:
•signal processing gear that produce hum
such as synthesizers, samplers and elec-
tronic drums
•Microphones for lead vocals, background
vocals, drums and other musical instru-
ments
•Microphones that are intermittently used
•Noisy digital and analog reverb and delay
devices
Special Applications
The 363X gating action can be controlled by an
external signal at the Key Input on the rear panel.
This is useful for applications such as frequency
weighted gating or anticipatory gating for zero at-
tack times.

Front Pandl dbx 363X
Figure 1: Front Panel
A. STEREO COUPLE switch and LED.
Depress this switch to activate Stereo-coupling
(CH 1MASTER, CH 2SLAVE). The LED next
to the STEREO COUPLE button turns on when
the 363X is actively stereo coupled. In Stereo
Couple mode, the THRESHOLD, HOLD and
RELEASE controls on Channel 2have no effect
on the gating action. The Channel 2OPEN,
HOLD and RELEASE LEDs track with Channel
1meters.
B. THRESHOLD control and OPEN LED
(CH 1and CH 2)
Adjusting this control sets the level at which
the gate will open with regard to the Input
level. The THRESHOLD control is calibrated in
dB from -60 to +20dB, to provide an 80dB oper-
ating range.
The green OPEN LED located above the
THRESHOLD control turns on whenever the in-
put signal (or Key Input signal) rises above the
set THRESHOLD level.

Front Panel
Figure 2: Front Panel
CHOLD control Lnd HOLD LED
(CH 1and CH 2)
The Hold function determines the amount of
time the gate remains open after the input sig-
nal falls below the threshold. The HOLD con-
trol is calibrated in seconds, with arange of 0
(OFF) to 3seconds.
When the HOLD function is used, the yellow
HOLD LED turns on as soon as the input level
falls below the threshold. The HOLD LED will
remain illuminated until the HOLD function
has completely timed out.
4

Front Panel dbx 363X
D. RELEASE control and RELEASE LED
(CH 1and CH 2)
The RELEASE control determines the rate at
which the gate closes once the signal at [the in-
put falls below the threshold and the HOLD
function is timed out.
The RELEASE control is calibrated from 3000 1
dB/second to 10 dB/second. :
The intensity of the red RELEASE LED will in-
crease as the attenuation increases. If the Re-
lease rate is set for afast release, the LED
illuminates quickly.
E. KEY MONITOR switch (CH 1and CH 2)
Depressing this switch allows the signal at the
KEY input to be routed directly to the audio
output. When KEY MONITOR is selected, all of
the front panel functions are inactive except BY-
PASS. i
F. KEY ENGAGE switch (CH 1and CH 2)
Depressing this switch causes the channel to re-
spond to the signal at the KEY input. When the
Key Engage switch is depressed and no signal
is present, the 363X does not pass ajny signal.
G. BYPASS switch (CHI and CH 2)
Depressing the BYPASS button creates a"hard-
wire bypass" of the 363X circuitry Ipy connect-
ing the input directly to the output!1
BYPASS overrides all controls, even if power is
removed from the 363X.
5

Rear Panel
Figure 3: Rear Panel
A. INPUT Connector (CHI and CH 2)
The signal input of the 363X is unbalanced and
can accept amaximum input level of +18dBu.
It requires aWHp/Sleeve phone plug.
B. OUTPUT Connector (CH 1and CH 2)
The signal output of the 363X is unbalanced
and is capable of driving +18dBu into a6000
load. It requires aWTip/Sleeve phone plug.
C. KEY Input (CHI and CH 2)
The KEY input is unbalanced and can accept a
maximum input level of +20dBu. It requires a
WTip/Sleeve phone plug.
D. AC Voltage Select Switch
Selects for use between 120VAC or 240VAC op-
eration. Be sure to determine the line voltage
before applying power to the 363X.

Rear Panel
E. AC power cable
Connect this cable to any 50Hz or 60Hz AC
power source of the correct line voltage, as
shown by the AC LINE VOLTAGE requirement
indicator above. Note that the 363X does not
have apower switch. It is recommended that
the363X be "ON" at all times. The Model 363X
consumes amaximum of 12 watts AC power.
WARNING: Be sure to verify both your actual
line voltage and the voltage for which your
Model 363X was wired, as indicated on the rear
panel of your unit. Connection to an inappro-
priate power source may result in extensive
damage which is not covered by the warranty.
dbx 363X
7

Connecting The 363X To Your System
The 363X can be used with any line-level device.
Some common examples include: mixing consoles,
musical instruments, patch bays, and signal proces-
sors.
A. Mixing Board:
If you wish to gate aparticular track of amulti-
track recording or one channel of alive per-
formance mix, the 363X output can be directly
connected to aline input jack, or wired to an In-
sert point.
8

Connecting The 363X To Your System dbx 363X
Figure 5: Connecting a363X to aGuitar
B. Musical Instruments (i.e., Electric Guitar,
Bass, Keyboards):
Because the 363X has an 80dB input range, the
output of an electric guitar can drive the 363X's
input. For greater sensitivity and improved sig-
nal to noise, it is recommended that the 363X be
connected to the "PREAMP OUT" of your gui-
tar amp (if so equipped), or the output of some
other device that is designed to accept low-
level instrument inputs (including various
stomp boxes, rack mount audio products, and
the dbx Performer Series processing units). Fig-
ure 5A shows the 363X connected between the
output of apre-amp and the input of apower
amp.
Microphones, like guitars, also typically have
low-level outputs. Therefore, it is recom-
mended that the 363X be connected after the
mic pre-amp.
In Figure 5B, the 363X is connected to the out-
puts of asynthesizer to gate out the constant
noise inherent in most keyboards. 9