UNIVERSAL AUDIO Model 175 B LIMITING AMPLIFIER
4
BALANCING ADJUSTMENTS
Inherent stability eliminates the need for frequent balancing of the 175 B.
However, if thumping is noticed or components are replaced, the unit should be
balanced as follows:
a.
If using TEST 1 position, remove any input signal from the amplifier.
b.
Set the attack and release controls to approximate mid settings.
c.
Rotate the input and output attenuators fully counter clockwise
(maximum attenuation).
d.
Set the meter switch to OUTPUT position.
e.
Set test switch to TEST 1 position.
NOTE: If desired, balanced can be performed by applying a 3-volt external
signal to the input jacks and setting the test switch to TEST 2 position.
f.
Rotate the output attenuator clockwise until an indication is observed on
the meter.
g.
Adjust first the PLATE BALANCE and then the CATHODE BALANCE
controls for minimum meter deflection.
h.
Rotate the output attenuator fully clockwise (zero attenuation).
i.
Adjust first the PLATE BALANCE and then the CATHODE BALANCE
controls for minimum meter deflection. Note meter indication.
j.
Adjust the PLATE BALANCE control slightly clockwise until a change in
meter indication is observed. Then attempt to adjust CATHODE
BALANCE control for meter indication less than noted in step i.
1)
If meter indication is less than that noted in step i, perform step j
repeatedly until absolute minimum meter indication is obtained.
2)
If meter indication is not less than that noted in step i, adjust the
PLATE BALANCE control slightly counter clockwise until a change
in the meter indication is observed. Then adjust the CATHODE
BALANCE control for minimum deflection. Perform sub-setup (2)
repeatedly until absolute minimum meter deflection is obtained.
