Ampex 351 - Page 20

SUMMARY
Component
New Value
200K ohms
50K ohms
14 db UNBAL BRIDGE
10 db BAL BRIDGE
66K ohms
33K ohms
CAUTION
NOTE
OVERALL PERFORMANCE CHECK
NOTE
3-5
UNBAL BRIDGE
30K ohms
60 CYCLE AMPLIFIER
The Ampex Model 375 Precision 60 Cycle
Amplifier can be plugged directly into the
equipment at J503S. No other connections are
necessary. The Model 375 is used where power
sources are erratic and there is need for a pre 
cision 60 cycle time base for driving the cap 
stan.
REMOTE CONTROL
The operation of the tape transport mechan 
ism can be remotely controlled by a Remote
Control Unit.
For Gain
Increase
10 db BAL BRIDGE
and UNBAL BRIDGE
NOTE
Whenever the remote control unit is
not connected, the dummy plug
P502P, supplied with the equipment,
must be plugged into J502S.
R1
R5
R5
R4
R1
R5
R4
33K ohms
12K ohms
zero (short out)
100K ohms
33K ohms
27K ohms
5.6K ohms
Make the following equipment performance
checks at the time of installation and when
necessary thereafter:
REPRODUCE (Playback) LEVEL
REPRODUCE (Playback) RESPONSE
REPRODUCE (Playback) NOISE
MEASUREMENT
RECORD CALIBRATION
FREQUENCY RESPONSE
RECORD NOISE MEASUREMENT
It should be noted that this machine
has been adjusted at the factory to
(Read SECTION 4, OPERATION before mak 
ing these checks.)
89-0144
Issue A
If this unit is used with the Recorder/
Reproducer, the control circuit fuse
F402 must be increased to 5 amperes.
New Input Impedance
BAL BRIDGE
66K ohms
Do not remove the dummy plug
P503P unless the 60 cycles amplifier
is connected.
PHONES
High impedance head phones must be used.
To monitor the incoming line or reproduce
output, plug the high impedance phones into
phone jack J6 PHONES on the amplifier face
panel or J4 MONITOR on the back of the
amplifier chassis. The monitor jack J4 is a
high impedance unbalanced output isolated
from the main line. To preserve low frequency
response, feed into an input impedance 50K
or higher. To preserve high frequency response
the cable should have not over 500 uuf of
capacitance.