Tandy CM-8 User Manual

8. Audio Output Circuit (Fig. 10)
The audio output circuit is an output transformerless
system which employs a bipolar analog IC. The audio
signal
coming out of the computer is applied via C301
and the buffer amplifier 0301 to pin (D of IC301. The
signal fed into
IC301 is delivered to pin ® through PRE -
DR IVER, DRIVER, and POWER-OUT.
The audio signal coming out of IC301 is sent via C303
to the speaker.
Characteristi cs in low -freque ncy band are determined
by C305 and C303; c haracteristi cs in high - frequency
band are determined by C308 .
The amplifi c ation factor of IC301 is determined by
R
30 7.
Power is supplied to IC301 through pin @.
+
When current does not flow through pin @, the volt -
age at pin@ is increased. Due to the increase in volt -
age, a current flows into 0302 through R310 and
D304 : 0302 is then turned on so that current flows
through R308 and the voltage at pin @ is decreased.
When current flows through pin @ of IC301, the volt -
age applied
to pin @ is decreased . If the voltage is
decreased,
the cu r rent through R310 and D304 is off
and 0302 is turned off , so that the current through
R308 is cut off , and the voltage at pin @ is increased.
Thus the volt age at pin @ of IC301 is stabilized.
R3 15
R3 14 C3 09
C3 1 I
0 3 0 1
SOUN D VOi.
R310
03 02
Figure 10 . Audio Output Circuit
12
03 0 2
R3 1 I
R3 01
+
C3 0 6
TO PIN ® +1 a v
OF FBT
TO SP
( 8 ohm )

Tandy CM-8 Specifications

General

Brand	Tandy
Model	CM-8
Category	Monitor
Language	English