Use Of The Dolby System On Fm Broadcasts; Fm De-Emphasis Switch; Explanation Of The Dolby Mode Chart - Marantz 4300 Owner's Manual

Mark the calibration positions on the recorder's
record and playback level controls to avoid the
necessity of re-calibrating after making a non-
Dolby recording.
IMPORTANT:
It will be necessary to re-calibrate the Dolby
levels when a change in tape speed has been made
or when a different brand or type of tape is used.
When the Dolby process is not desired on a re-
cording, record in the normal manner - adjusting
the record levels with the recorder's record level
controls. DO NOT change the 4300's PLAY
CAL controls.
USE OF THE DOLBY SYSTEM ON FM BROAD-
CASTS
Your Model 4300 is equipped to receive Dolby-
ized FM broadcasts.
Most FM broadcasts do not currently use the
Dolby Noise-Reduction system. To receive FM
broadcasts which are not using the DOLBY
Noise-Reduction System, leave the DOLBY
Switch in the "OFF" position. However, if a local
station is broadcasting a Dolbyized FM signal,
full advantage of the increase in signal-to-noise
ratio may be obtained by putting the DOLBY
Switch in the "DOLBY FM" position. The rear
panel DOLBY FM PRESET LEVEL controls are
factory-adjusted. Do not change the position
of these controls.
FM DE-EMPHASIS SWITCH
This rear panel switch operates only when the
front panel DOLBY Switch is in the "DOLBY
FM" position. It alters the frequency response
of the FM signal. Normally, this switch should
be left in the
75~S
position. However, if the
station is broadcasting the Dolbyized signal using
a 25~S pre-emphasis, put this switch in the
"25~S" position to obtain flat FM frequency
response. If in doubt, call the station.
EXPLANATION OF THE DOLBY MODE
CHART
This chart indicates the correct DOLBY Switch
positions for various types of input material.
The input format is indicated in the left column
and the appropriate DOLBY Switch position,
together with FM DE-EMPHASIS Switch position,
is shown under the appropriate mode of opera-
tion.
~
De-Emphasis
Dolby Switch Position
ode
Switch
Record
Notes:
Input
Position
Listening
Without Dolby With Dolby
F.M.
75~ "Off" "Off" "Record I"
-
(Normal)
F.M.
If there is a doubt regard-
with Dolby 75~s "Dolby FM"
" Record II" "Dolby FM"
ing the pre-emphasis used on
75~s
the transmission, the F.M.
Pre-emphasi~
station should be contacted,
: .;
.
where possible, to ensure cor-
F.M.
with Dolby
"Dolby FM"
rect position for de-emphasis
25~
25~
"Dolby FM" "Record II"
switch.
Pre-emphasis
Non Dolbyized
sources
-
"Off"
(Phono, Tape,
"Off" "Record I" Pre-recorded tape manufac-
Aux inputs,
"Record I"
turers indicate when the ma-
A.M.) terial has been recorded in a
Dolbyized format. Home re-
Dolbyized
corded tapes should also be
sources (de-
clearly marked as to format,
rived from "Play"
"Record II" "Play"
to ensure correct play back
"Tape" or
-
"Record II"
mode.
"Aux" inputs
etc.)
For initial calibration, utilizing the Dolby standard alignment tape, see detailed instructions
on Pages 14 thru 16 of this manual.
Table 1. Dolby Mode Chart
16