Tandberg 3B Mono Schematic

Page 1

TANDBERG TAPE RECORDER
MODEL 33 (mono)

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3. ADDITIONAL DESCRIFIION OF MODEL SB.

The driving mechanism of model SB ls iden-
tical with the mechanism at model 3 Stereo
Fig. 30 shows the cirauit diagram of model 3 B
lhe amplifier is almost identical with the am
pliiier ior upper track in model 3 Stereo with
exception of the special features which are
necessary in connection with the stereo -
monaurel swilch, 'lhe electrical description ol
the amplifier lor upper troclt therelore also
goes for model 3 B. with exeption of the two
lollawing points.

1. The output switch connects in the left posi-
tion (seen from front of the recorder) the
output transformer to both the output termi<

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nals and the monitor speaker, In the mid
position the output transformer is only con-
nected to the output terminals. In the right
position the output transformer is connected
to the monitor speaker, while the terminals
marked P.U. are connected to the output
terminals. Hi 5 done to ease the use when
both the tape recorder and a record-player
are intended to be played back through
the some external amplifier (or rudlo set).
To do this, one connects the output from
the record-player to the terminals marked
P.U. and the output terminals to the input
of the external amplifier, When playing tape
recordings. the output switch is placed n
mid position (or in the left position if it Is

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desired to listen simultaneously to the moni-
tor speaker). When playing records. the out-
put switch is placed in the right position.

. In the record position the loudspeaker and

output translormer are disconnected from
the output terminals and these get sig-
nal lrom the second plate of the ECC83
via a voltage divider Rss-Rucl Mohm-
10 Kohms), thus giving opportunity to mom
tor the recorded program through head-
phones or an external amplifier. The output
impedance is 10 Kohms. Because of the
great value of R3; the output terminals can
be shorted without affecting the recorded
program.

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