Ampex 351 Series User manual

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DESCR fPTION AND PERFORMANCE CHA RA CTERSTICS
GENE RAL . . . . . . . . ..
PERFORMANCE ClIAR AC T ERSTICS .
EQU IP MENT AVAILAB LE
lNSTALLATION ,
GENERAL.
TNTERCONN£CT I NG
MOUNT I NG
POWER CONNECTION
OUTPUT
I NPUT
SUMMAR Y
Pl JONES
REMOTE CONTROL
60 CYCLE AMPLIFIER
OVER - ALL P~: HFORMANCE CII ECK
D IS TORT L ON .
FLUTTER AND WOW .
OPERAT I ON
GENERAL .
SUMMA HY OF CON THOLS , SW IT CHES AND I ND I CATO RS
OPERATING TEC ll Nl QUES .
T
II E DEVELOPMENT AND T H EORY OF MAGNGTlC TAPE R ECORDING
TII EORY Of MAGNET IC TAPE RECORD I NG . .
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TAPE
rRANSPORT
MECIIANISM
.
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AMPEX SER IES 351 RECORDER ; REPRODUCER -¾ VJF:W
RACK l..J\YOUT (
l\fODEL 351-2) . . . .
CENTER 'I AP GROUNDED BALANCED OUTPUT AND
STRAPPING FOR 4 VU OUTPUT . .
MICROPIIONES WITH 50 OI IMS OR LESS IMPEDANCE
Il[GII IMPEDANCE MI CROPHONE INPUT .
INT ERCONNECTING - S INGL E TRACK
lNTERCONNECTTNG , . , . , ,
TAPE TIIHEAOING PATH
VALDEMAR POULSEN
MAGNETIZATION UF TAPE
RECORD IIEAD . . .
RECORDING MEDIUM MAGNETIZATION CURVE.
REPRODUC8 IIEAD CIIARACTERS TJ CS
ACII I
EVING FLAT OVER -ALL RESPONSE
COMPONENT ANO ASSEMBLY CALLOUTS
TAPE TENSIONING
TAKE - UP AND REW I ND MOTOR ASSEMBLIES
CONTROi . CIRCUIT BOX . . .
DEMAGNETIZING TIIE HEADS
CONTROL cmcurr BOX CALLOUTS
CAPSTAN fOLER PRESSURE MEASUREMENT .
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BRAKE BAND REPLACEMENT_
REMOTE CONTROL
SCHEMATIC DIAGRA l \11 TAPE TRANSPORT CO 1 TROL
CIRCUlTS ( FOLDOUT SHEET )
SIMPLIFIED CONTROL CIRCUIT SCHEMAT IC
MODEL 351 TAPE TRANSPORT ( FOLDOUT SHEET )
HALF -T RACK IIEAD ASSEMBLY
FULL - TRACK 1IEAD ASSEMBLY
TWO-TRACI<
IIEAD ASSEMBLY
STANDARD 351 HEAD CONFIGURATIONS
LOCATION OF ELECTRONIC SUBASSEMBUES
AMPLIFIER CHASSIS, FRONT PANEL
AI\IPLIFIER CJIASSTS. REAR VIEW
BLOCK DIAGRAM.
RECORD CIRCUIT
BLOCK DIAGRAM,
REPRODUCE CIRCUIT
IIEAD AZIMUTII ADJUST IVIENT
SIGNAL-TO-NOI
SE RATIO COMPUTATIONS
MI CROPHONE RESPONSE SET-UP
SYSTEM BLOCK DIAGRAM
TROUBLESHOOTING TIIE REPRODUCE AMPLIFIER
TROUBLESHOOTING THE RECORD AMPLIFIER
APPLICABLE RESPONSE CUllV l•;S ( TWO FOLDOUT SHEETS )
PARTS LOCATION ( ETCllED BOARDS) ( ONE FOLDOUT SHEET )
SCHEMATIC DJAGR!\iv!S ( TllREE FOLDOUT SIIEETS ) _
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SECTION 1
ND PERFORMAt~CE
CHARACT RISTICS
GENERAL
The AMPEX Series 351 Magnetic Tap e Re-
cor der/ Reproducers arc high quality precisfon
instruments designed for th e professional us er
who requires the finest and mos t faithful r e-
cording and reproduction.
A basic recorder/reproducer in
the 351 ser ies
consists
of a tape tran spo rt for operat ion at
t ape speed pairs of 3¾ in ch es per second (ips)
and 7½ ips or 7½ and 15 ips; a h ea d assemb ly
for u
se with th e ¼- in ch magnetic tape; a nd an
electron
ic assembly which co ntains the record
amplifier. reproduce arnpUfier, bias
and e ras e
oscillator,
and power supply -all featuring
etc h ed board const ru c Uon .
NOTE
T/zis manual is primarily intended for
reco
rd ers using Ampex Catalog Num-
ber 30960 electronics. In instances
-where there are significant differences
between this elec tron ics assembly and
earlier models us in g Catalog Number
30750 or 30950 electronics an appro-
priate
notation will be fozmd.
H ead assemb li es for either full (si ngl e)
tra ck, half tra ck or two track stereo phonic
(351-2) operation are available.
CCIR e
quali zation can be obtained on request
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when ordering equi pment.
Several mounting arrangements are offered
-c onsole, tw o case po rta ble, and rack mount.
In the portable equipment, one case contai ns
the tap e transport and th e other hou ses th e
electronic assembl
y.
Tap e Width
Tape Speed Pairs
Frequency Response
Signal-to-Noise Ratio
Flutter and Wow
Recording or
Reproducing Time
(NAB 1O½ In ch Diam eter
Reels, 2400 feet of tape)
Starting Time
Stopping Time
Reprodu ce Timing
Accuracy
Rewind Time
PE RF ORMANCE CHARACTERISTICS
¼-inch
3¾-7½ ips
7½-15 ips
Speed (ips)
3¾
7½
15
R esponse (Cycles per second)
+ 2 db 50 to 7,500
+2 db 40 to 10,000
-+-4 db 30 to 15,000
± 2 db 30 to 15,000
Speed (ips) P eah Record Level to
Unweighted Noise ( db )
3¾ 50
7½ 60 full track
55 h
alf track or two track
15
Same as 7½ ips
Peak reco td level is that level at which the overall (input to outp ut )
t
ota l rms h armo ni c di stortion do es not exceed 3 percent when
measured on a 400 cycle tone. Noise is m easure d when erasing
a signal of peak recor din g level in the absence of new signa l. Bias,
erase and r ep r od u ce amp lifi er noise are includ ed in the m eas ure -
ment. All frequencies between
50 and 15,000 cycles are m eas ured.
Speed (ips) Flutt er and Wow
(per cen tag e rms)
3¾ .25%
7½ .2 %
15 .1 5%
Flutter and wow measurements include all co mp onents between
0
and 300 cycles using an rms value of const ant amp li tude s in e
wave flutter.
Speed (ips)
3¾
7½
15
Half Track
(hrs) (min)
4 16
2 8
1 4
Full T rack
(hts) (m in )
2 8
I 4
32
The tape is accelerated to full speed in less than 1/ 10 of a second.
When operating at 15 ips, the tap e moves less than two inches
after the S TO P button is pressed.
Accuracy
( percentage )
±. 2%
Accuracy
(sec ond)
+ 3.6
Length of Re cording
(min)
30
Approximately 1 minute for a full 2,400foot NAB reel.
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