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and is led to J611. The signal is then discriminated in the frequency and level by the dynamic
filter consisting of H611, H613, H615 and H617, and is fed back to the mixing circuit.
In the playback mode of operation, a part of the output signal (at J607) is led to J611 and
discriminated in the frequency and level by the dynamic filter consisting of H611, H613, H615
and H617 and fed back to the mixing circuit.
10. 400HzTONE
The 400Hz tone signal which is a 580mV, 400Hz sine wave is available at the TAPE
MONITOR OUT terminal at any position of the DOLBY switch (with the exception of the
RECORD II position) and SELECTOR switch.
The output signal of the 400Hz oscillator consisting of HL01 and HL02 is delivered through
the emitter follower HL03 to JL02 and JL03. The output levels at JL02 and JL03 are adjusted to
580mV and-approximately 50mV, respectively.
The signal fed from the Dolby Unit P.W. Board (P600) comes to JL04 and is rectified
through HL06. The rectified output at JL06 is led to the meter M002.
11. DOLBY SWITCH
This switch sets the Dolby noise-reduction circuit for record or playback and also switches
the meter from the AM or FM SIGNAL STRENGTH mode to the DOLBY CAL LEVEL mode,
or vice-versa. With the DOLBY switch placed in "OFF" position, the meter will be used as a
SIGNAL-STRENGTH meter; in all other positions as a DOLBY CAL LEVEL meter.
11.1 DOLBY FM
This position is used to listen to Dolbyized FM broadcasts. The Dolby FM level has been pre-
adjusted at the factory.
11.2 PLAY
This position is used to play back a Dolbyized source (except FM).
11.3 OFF
With this position, the Dolby circuit is by-passed and the input signals are directly fed to both
TAPE MONITOR OUT jacks and amplifiers.
11.4 RECORD I
For making a Dolbyized recording from an in-coming "flat" (non-Dolbyized) signal. When
the MONITOR switch is in the SOURCE (out) position, the "flat" signal will be heard. When the
MONITOR switch is in the TAPE (in) position, the Dolbyized signal from the tape will be heard.
11.5 RECORD II
For making a "flat" (non-Dolbyized) recording from an in-coming Dolbyized signal.
Regardless of the position of the MONITOR switch, a "flat" signal will be heard.
12. RECORD LEVEL (L) AND (R) KNOBS
These knobs control the record level of the signals to be recorded through the Dolby Unit.
Adjust the knobs so that the Level Meter pointers on the tape recorder do not exceed the 0VU
level.
13. PLAY CAL. (L) AND (R) KNOBS
These knobs adjust the playback outputs from a tape deck to the proper Dolby level.
14. DOLBY FM PRESET LEVEL CONTROLS;
These factory-adjusted controls govern the FM output level to the Dolby circuit. These
controls are for the use of a qualified technician only.
Digitized in Heiloo Netherland
5/30/2017
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