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4 - 2 : A M P L I F I E R M O D U L E
Refer to the amplifier circuit diagram:
A. lp*91lggtiqql
1. Solid state; 3 lC's 7 rransistors {g transisrors
for -3 type)
2. Ourput power: 20 watts RMS I ahm load
3. Distortion; Less than 4o/o at 40OHz
{measured with SMpTe 400H2
Signal Level Tesr Fitm|
Less than 19lo at I KHz
{measured wirh SMPTE Mutti.
Frequency Test Film)
4. Wow & Flutrer: Less than 0.2% WRMS.
5. Frequency response:
Optical 50Hz - 7000H2 t 4db
Magnetic 5CIHz * l0000Hz t 4db
Magnetic Recording Range 50Hz
l0000Hr
6. S/N ratio of the amp: 60db
7. Mic input impedance; 6O0 ohm and up.
8. Mic input level: 1Ornv max (high or low imped-
anse for -2 type and high irnpedance only for
-3 rype.)
9. Phono input level: 50rnv {high impedancc}
l 0 S p e a k e r J a c k s : 8 o h m
B. Amplifier Power Supply Circuit. {r*r-nj6,47)
40 volts AC power ro thc arnplifier is supplied
from the transformer secondary windings through
pins #l & 2 sf the 9 pin socket (MT-91.
FUSI 2A
-- d\9
(NOT[: NT proiectors after SIN ?6135 and NST
after S/N 10674 are supplied \'/irh 36V
AC standard and 40V AC oprional" Sce
Sec. 4-4 TRANSFORMER MODULF,)
Dual diodes 51 and 52 form a bridge rectifier,
[iltered by capacitor C44, providing the amplifier
approximately 56V DC {or 50V DC). The 8V AC
transformer secondary winding supplies AC exciter
lamp voltage through pins 14 and #5 of the 9 pin
socket. Dual diodes 53 and 54 form a bridge
rectifier which is filtercd by capacitor C14. Cl5
and Cl6 are ripple filters regulating the base input
voltage to TR-l 's base. R-32 is a current *nse
resistor serving as feedback to the base of TR-2
through R-29.
TR-2 is a protector for this regr.llating circuit.
TR-l is the DC regulator for the approximately
3.5 volts to thc cxcitcr lamp, routed through pins
*8-9 of the 9 pin socket,
ln -2 rype magnetic playtrack the excitrr lamp
voltage is switched off, while in -3 type magnetic
playback this switch is not provided.
c. |qdi" Ampllktltrsgl
The input signal from the solar cell or magnetic
head is accomplished through rcspccrive miniature
iacks in the top of the amplificr chassis. (See Fig.
*4t)
Fig. s47
S P . J f o r F r o n t
Cover Speaker
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