Ampex 351 - Page 28

4-5
Reproduce (Playback)
To reproduce a previously recorded tape,
turn the METER and OUTPUT SWITCH 4S3,
to the extreme left position designated PLAY 
BACK LEVEL, then start the tape in motion as
indicated under PLAY. A PLAYBACK LEVEL
Control 4R36 has been provided on the front
panel to adjust the tape level to plus 8 vu out 
put (zero on the vu meter).
Half Track Operation
The tape is threaded and operated as de 
scribed under TAPE THREADING and TAPE
MOTION. However, only the upper half of the
tape will be used on the half track equipment.
To utilize the lower half of the tape, the full
reel on the takeup turntable should be removed,
turned over and placed on the tape supply turn 
table upside down. Place an empty reel on the
takeup turntable. Repeat the operation as per 
formed on the first track.
NOTE
For correct meter Calibration it is im 
portant that the line out be properly
terminated in a nominal. 600 ohms
either external to the machine or by
the use of the line out termination
switch (LINE TERM)5S4.
f
When the program level is properly set, start
the tape in motion as indicated under PLAY.
CAUTION
Never press the STOP and PLAY but 
tons in rapid sequence when the tape
is traveling at high speed in the RE 
WIND or FAST FORWARD modes.
This will almost invariably break the
tape since it does not allow the tape
to stop before the capstan idler locks
it to the capstan.
39-0144
Issue A
Then press the RECORD BUTTON 4S6. The
record indicator 411 next to the record button
will now glow and the equipment is recording.
The erase position of the METER AND OUT 
PUT SWITCH provides for metering of erase
current. The erase current is not critical and
has been factory adjusted to read approximately
— Va on the vu meter for half track and stereo 
phonic heads and +1 for full track heads. Both
the erase and bias current will vary directly with
line voltage. The bias current is more critical
and is factory set to read zero at 117 volt line
voltage, using an average tape. It should read
between — 1/2 and + Vz for optimum high fre 
quency response at 7 ] /a and 3% ips using a me 
dian tape. For the flattest possible response with
a given tape, the bias can be reset as described
in the “ Alignment and Performance Checks"
paragraphs of SECTION 8.
The bias is adjusted by means of BIAS AD 
JUST capacitor 5C13, located on the electronic
chassis. The meter calibration for bias measure 
ment can be checked as indicated in SEC 
TION 8.
Record
To record a new program on previously re 
corded tape, or on blank tape, turn the METER
and OUTPUT SWITCH 4S3 to the second posi 
tion from the left which is designated RECORD
LEVEL. Turn the RECORD LEVEL CONTROL
4R9 clockwise until the level reads 0 (zero) on
the vu meter on the most intense program
peaks. The program can be audibly monitored
through cither the phone jacks (PHONES)
4J6, Monitor 5J4, or the line out connector
(LINE OUTPUT) 5J5 before the tape is in
motion. This direct monitor feature allows the
program to be set up through the machine
without actually recording during the set up
period.
Notes on Stereophonic Operation
Because the stereophonic equipment has a
separate erase feature, permitting either track
to be erased independently of the other, it is
necessary to press the RECORD buttons on
each amplifier to place both amplifiers in the
record mode.
When using the remote control unit the
single RECORD button will energize both elec 
tronics (concurrent record feature).