Akai GX-221D User Manual

Vill. AUTOMATIC NOISE REDUCTION AMPLIFIER
ADJUSTMENTS (Model GX-225D only)
NOISE REDUCTION P.C. BOARD
LEFT CH. VR2 300KB
LEFT CH. VRI IKB 1. A.N.R. AMP. ADJUSTMENT
RIGHT CH. VRib IKB
RIGHT CH, VR2b 300KB
1) Connect ‘the various measuring instruments as
shown in Fig. 24.
2) Set recording level adjustment volumes VRIla
50 kA (Left Channel) and VR1b 50kA (Right
Channel) to maximum.
3) Set the Noise Reduction Switch and the 8.0.8.
Switch to OFF position, and set Monitor Switch
to SOURCE.
4) Set tape deck to recording mode, and supply a
100 Hz signal to the line input terminals from the
Audio Frequency Oscillator. Adjust attenuator to
obtain a high sensitivity V.T.V.M. indication of
4 dB (VU meter indication “0” VU).
5) Adjust Noise Reduction P.C. Board semi-fixed
resistors VR2 300 kB (Left Channel) and VR2b
30 kB (Right Channel) shown in Fig. 30 so that
when the Noise Reduction Switch is set to ON
position, a line output level of 4 dB is maintained.
6) Return Noise Reduction Switch to OFF position
and set the oscillation frequency of the Audio
Frequency Oscillator to 10 kHz. Then adjust the
attenuator to obtain the same results as outlined in
Item 4) above.
7) Set Noise Reduction Switch to ON position, and,
at this time, adjust Noise Reduction P.C. Board
semi-fixed resistors VR1 1 kB (Left Channel) and
VR1b 1 kB (Right Channel) shown in Fig. 30 to
obtain a line output level decrease of 2.5 dB.
8) After the adjustments in Items 1) through 7) have
been completed, decrease the 10 kHz signal by
VR2b 300KB VRIb IKB VRI IKB_ VR2 300KB 30 dB and supply this signal to the line input.
Pa ee EERE ie Confirm that the line output level is 6 + 0.5 dB
lower when the Noise Reduction Switch is at ON
Fig.31 AUTOMATIC NOISE REDUCTION AMP. P.C. position than when at OFF position.
BOARD (Face Side)
TRl, 5-- esc7it ©
© @ © @OO TR2,3,4- ascases ©,
or 2SC871 ©)
Fig.32 AUTOMATIC NOISE REDUCTION AMP. P.C. BOARD MS-5215 (Reverse Side)
22

Akai GX-221D Specifications

General

Brand	Akai
Model	GX-221D
Category	Tape Deck
Language	English