Protech Audio 2000 - Manual (Page 6)

HIGH PASS FILTER & TONE CONTROLS -
Each input card has a slide switch selectable high-
pass filter. Each input card slot has individual Treble
and Bass controls. The Model 2000 is shipped from
the factory with the high-pass filter in the "IN"
position. The BASS and TREBLE tone controls are
set to the "FLAT" position. Counterclockwise rota-
tion "CUTS" frequencies, while clockwise rotation
"BOOSTS" frequencies.
The corner frequency of the BASS control is 315Hz,
with a peak at 50Hz. The corner frequency of the
TREBLE control is 1150Hz, with a peak at 10KHz.
GAIN -
Each input card has individually adjustable gain.
The gain is preset at the factory. Before any field
adjustments are made to the Model 2000, it is strongly
recommended that the unit be installed, wired,
turned on and listened to. If additional gain adjust-
ments are necessary, they may be made in one
of two ways.
(NOTE: If ALC option is used,
switch ALC to "OFF" position, before adjusting
gain trimpots.)
First, there is a gain setting slide switch on the input
card assembly. This switch allows the preamplifier
gain to be set to either 30dB or 50dB. This switch is
set to 50dB at the factory. Most applications will
require the 50dB setting. The 30dB setting is
recommended for condenser type microphones.
Second, each input card slot has a VCA 1 gain
adjustment trimpot mounted on the backplane as-
sembly. The trimpot is set at the factory for -6dB. The
gain settings correspond to "clock" positions with
12:00 being straight up. Additional settings are as
follows:
WEIGHTING CONTROL -
Each input card slot has a "WEIGHTING" control
trimpot. The Model 2000 is shipped from the factory
with the "WEIGHTING" control in the maximum
clockwise position. Most applications will require
this setting.
The "WEIGHTING" control is the send for the auto-
mixing "pre-mix". Weighting reduction can be used
when it becomes necessary to balance the automatic
mixing action separately from the audio mix. One
situation would be where one microphone is near an
air vent, and the noise of the air vent makes the gain
go to that microphone when no one is talking. The
weight for that channel can be backed off so the auto-
mix gains balance. The ambient weighting can be
skewed up to 10dB without affecting the mixing of
the voice signals. The weight is normally left at
maximum position (full clockwise) for maximum
dynamic range in the auto mixing system.
PHANTOM POWER -
Each input card has a 3 pin terminal strip to allow
jumpering for phantom power. A red push-on jumper
is supplied for each input card. By placing the jumper
on the #2 and #3 terminals, the card will supply
15VDC phantom power to the microphone. By plac-
ing the jumper on the #1 and #2 terminals, the card
will allow 48 volt phantom power to be supplied
from an external source. Each input card is individu-
ally configured. The unit is shipped with the jumper
in the external 48 volt position.
MUTE, INPUT MUTE & GROUP MUTE -
Each input card has a MUTE slide switch, used for
troubleshooting.
Each input card has a separate mute pin. Grounding
this pin will mute the input.
Each input card has a slide switch that enables the
card to be attached to a group mute function. Ground-
ing the Group Mute pin on the Master card slot will
mute all inputs attached to the Group Mute function.
The input cards are shipped with the GROUP MUTE
enabled.
MIX-MINUS - see page 12 mix-minus section.
AUTOMATIC/MANUAL OPERATION
Each input card has a slide switch that allows the
individual card to operate automatically, or manu-
ally .
AUDIO INPUTS
-35dB
-33dB
-27dB
-20dB
-15dB
-6dB
0dB - Recommended
+6dB
+11dB
+17dB
+18dB 7:00 =
8:00 =
9:00 =
10:00 =
11:00 =
12:00 =
1:00 =
2:00 =
3:00 =
4:00 =
5:00 =
- Page 6 -
MASTER
EXTERN.
AUTOMATIC LEVEL CONTROL (ALC) CARD ASSEMBLY
(Mounted on Master Output Card Assembly)
WINDOW
TARGET RATE
ON
OFF
B
C
D
A
E
G
F
- Page 15 -
ALC Active.......................
(Level Gate)......................
ALC Gain Indicator...........
ALC ON-OFF Switch........
RATE Trimpot..................
TARGET Trimpot.............
WINDOW Trimpot............ A-
B-
C-
D-
E-
F-
G- Indicates active ALC function
N/A
Displays gain reduction.
Used for set-up
Controls speed of ALC action.
Controls desired output level.
Controls "dead zone" for dynamic range function.
NOTES:
ALC FEATURES