Advertisement
Adjusting the ANRS Circuit
Measuring instruments required for adjustment:
Audio oscillator (OSC), attenuator (ATT), high-sensitivity vacuum tube voltmeter, and oscilloscope.
Connection:
Remove the wires of input side of the ANRS, and connect wires as illustrated in Fig. 25.
Adjustment:
hs
4. Repeat the adjustment in 2. above.
NN
Disconnect the red lead wire from the power source of the bias oscillation circuit. Turn on the ANRS
switch, and push the record button.
. Apply a frequency of 5 kHz —70 dB to the input of the ANRS
circuit and adjust the semi-fixed
resistor, R320 (R420) so that the output of the ANRS circuit is —60 dB.
—45 dB.
ANRS control circuit
are
Non-linear
control element IZce
. Apply 5 kHz —70 dB to the same input so that the output of the semi-fixed resistor R315 (R415) is
. Make sure that there is no deformation in the wave form.
. Connect the lead (which is removed in 1. above) as it was.
Vbe = large
Response
Vbe = small
Variation of Vbe
(db)
100
IK
10K
Frequency (Hz)
Fig. 24
CD-1667, 1667U
Fig. 25
a
Advertisement
