Ampex 351 - Page 25

TAPE SPEED S503
S2
S504
S3
RECORD LEVEL
R9
4-2
METER AND
OUTPUT SWITCH
(FUNCTION SWITCH)
Item
POWER
OFF-ON SWITCH
HIGH
SPEED
Electronic
Assembly
front panel
Tape Transport
Tape Transport
control cluster
Electronic
Assembly
front panel
Electronic
Assembly
front panel
Location
Electronic
Assembly
front panel
Adjusts tape tensioning circuitry for the reel
size used.
sembly front panel.
Another MONITOR AMPLIFIER phone jack
and a line termination (LINE TERM) OFF-ON
switch are located on the back of the amplifier
chassis.
89-0144
Issue A
OUTPUT switch so that (reproduce) PLAY 
BACK, RECORD, BIAS and ERASE LEVEL(S)
can be read. A phone jack (PHONES) for
monitoring, a RECORD button, a RECORD
INDICATOR light, and a POWER OFF-ON
switch are also mounted on the electronic as-
Fn notion
Controls power to the electronic and mechan 
ical assemblies. When power is on capstan
will rotate if tape is properly threaded or
the safety switch is mechanically closed.
The v-u meter lamps light when power is
on, and are unaffected by the safety switch,
remaining lighted till the power is turned
off.
For stereophonic 351-2 operation POWER
switches of both electronic assemblies must
be in the ON position.
Determines speed of the capstan drive motor
by high or low speed winding. Used in con 
junction with EQUALIZATION switch S2.
Used to select appropriate equalization cir 
cuitry for tape speed chosen.
EQUALIZATION
LOW
SPEED
REEL SIZE
LARGE SMALL
SWITCH
The switch is closed when (LARGE position)
NAB lOW inch reels are used. In the SMALL
position the switch is open, connecting re 
sistance R502 in series with the torque
motors, thereby reducing holdback and take 
up tension.
Provides a means for switching the meter
to read indications of record input, erase and
bias, and reproduce output.
In the reproduce (PLAYBACK) position, the
meter indicates the signal level at the second 
ary of the output transformer. In the RE 
CORD position the meter indicates a “ flat ”
reading of the input signal. (See Figure of
System Block Diagram).
Adjusts record level.
SUMMARY OF CONTROLS, SWITCHES AND INDICATORS
Schematic
Reference
Symbol
S-5