UNIVERSAL AUDIO Model 175 B LIMITING AMPLIFIER
2
OPERATION
GAIN
The gain of the amplifier can be changed by altering resistance in the grid
circuits of V1. Jumpers have been provided for this purpose (see schematic
diagram). Unless otherwise specified, the unit is wired with the two jumpers
connected for low gain (24 dB). If desired, the jumpers can be relocated to the
high gain (37 dB) position.
VU METER
Unless otherwise specified, the 175 B is wired for +8 dBm zero reading on the
VU meter. If desired the VU meter can be wired for a +4 dBm zero reading by
relocating a jumper wire in the meter switching circuit (see schematic diagram).
Terminals provided on the rear of the unit for connecting a remote VU meter. A
strapping arrangement on the VU meter terminal board (see schematic diagram)
allows the remote VU meter to perform gain reduction while the internal meter
is still usable to indicate input and output level.
ATTENUATORS
The input and output attenuators are both adjustable from 0 to 40 dB. For this
reason the 175 B may be utilised at any point in the system where input signal
level is between -24 dBm and +13 dBm. The attenuators are adjusted for proper
operating levels as follows:
a.
Rotate the input and output attenuators fully counter clockwise
(maximum attenuation).
b.
Interconnect the unit with the system through either the input and output
jacks on the front panel or the terminal strip on the rear.
c.
Feed a sample of the program material into the system.
d.
Set the meter switch to GR position.
e.
Decrease attenuation with the input attenuator until the desired amount
of limiting is observed on the meter (limiting should not exceed 3 to 4 dB
except where the program material contains extremely loud peaks).
f.
Set the meter switch to OUTPUT position.
