Studio Technologies ISS - Manual (Page 42)

ISS User Guide Issue 3, June 1990
Studio Technologies, Inc. Page 43
ISS
Setting the Left Channel for Maximum
Attenuation
1) Connect the common lead of the AC
voltmeter to the COM test point. Con-
nect the other lead to LEFT OUTPUT
test point.
2) Connect the common lead of the audio
generator to the COM test point. Con-
nect the high lead to one end of the 10k
resistor. Use the jumper wire to connect
the other end of the resistor to the
junction of U5 pin 2, C22, and R16. You
can get at this point by connecting to
the bottom of R16. The 10k resistor is
acting as a summing resistor to feed a
signal into the inverting input of an op
amp.
3) Adjust 10-turn trim pot R25 to give a
minimum reading on the AC VTVM. You
are nulling the left channel crossfade
circuit. A normal level when nulled for
minimum would be –45 to –60dBu.
There is no exact correct value.
Setting the Right Channel for Maximum
Attenuation
1) Connect the common lead of the AC
voltmeter to the COM test point. Con-
nect the other lead to RIGHT OUTPUT
test point.
2) Connect the common lead of the audio
generator to the COM test point. Con-
nect the high lead to one end of the 10k
resistor. Use the jumper wire to connect
the other end of the resistor to the
junction of U5 pin 13, C9, and R18. You
can get at this point by connecting to
the bottom of R18.
3) Adjust R6 to give a minimum reading
on the AC VTVM. You are nulling the
right channel crossfade circuit. A nor-
mal level when nulled for minimum
would be –45 to –60dBu. Again, there
is no exact correct value.
4) This ends the procedure.