ampex model 601 - Steam Powered Radio

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AMI EX
Operation
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Maintenance
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AiMPEX
CORPORATION
.•14 CHARTER STREET
BEWOOD CITY • CALm>BMA
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AMI >EX
Operation
M O D E L 601
Viaintenance
Manual
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AMPEX
CORPORATION
934 CHARTER STREET
REDWOOD CITY - CALIFORNIA
Table of Contents
Page
I - l
1-1
1-2
I.
DESCRIPTION AND SPECIFICATIONS
GENERAL
SPECIFICATIONS
n.
PRINCIPLES OF OPERATION
THEORY
2-1
2-1
HI.
I N S T A L L A T I O N AND O P E R A T I O N
GENERAL
POWER
LINE INPUT
MICROPHONE I N P U T
REPRODUCE O U T P U T
INTERCONNECTING
CONNECTORS
STUDIO I N S T A L L A T I O N
TAPE THREADING
R E C O R D I N G W I T H H A L F T R A C K MACHINES
REPRODUCING W I T H H A L F T R A C K M A C H I N E S
RECORDING
REPRODUCING
REWIND AND FAST FORWARD
ERASING
MIXING
SYNTHETIC REVERBERATIONS
3-1
3-1
3-1
3-1
3-1
3-1
3-2
3-2
3-2
3-3
3-4
3-4
3-4
3-5
3-5
3-5
3-5
3-6
IV.
T A P E TRANSPORT ASSEMBLY
GENERAL
S T A N D - B Y OPERATION
P L A Y MODE
REWIND MODE
FAST FORWARD MODE
ROUTINE MAINTENANCE
4-1
4-1
4-1
4-1
4-3
4-3
4-4
V.
E L E C T R O N I C ASSEMBLY
GENERAL
RECORD C H A N N E L
REPRODUCE C H A N N E L
BIAS AND ERASE O S C I L L A T O R
ELECTRONIC A L I G N M E N T
A L I G N M E N T A N D TEST E Q U I P M E N T REQUIREMENTS
5-1
5-1
5-1
5-1
5-1
5-2
5-2
VI.
PARTS L I S T
6-1,
3rd E D I T I O N
O C T O B E R 1958
List of Illustrations
F i g . No.
Caption
Page
FRONTISPIECE
2-1
2-2
2-3
2-4
2- 5
3- 1
3- 2
4- 1
4-2
4-3
4 -4
5- 1
5-2
5-3
TAPE MAGNETIZATION
RECORDING H E A D
M A G N E T I Z A T I O N CURVE
O U T P U T VS. FREQUENCY
A C H I E V I N G F L A T RESPONSE
SPACE REQUIREMENTS
T A P E T H R E A D I N G AND N O M E N C L A T U R E
M E C H A N I C A L OPERATION S I M P L I F I E D
ROUTINE L U B R I C A T I O N
T A P E TENSION MEASUREMENTS
T A P E TRANSPORT E X P L O D E D V I E W
REPRODUCE A M P L I F I E R RESPONSE
RECORD A M P L I F I E R RESPONSE
SCHEMATIC D I A G R A M
2-1
2-2
2-3
2-4
2-5
3-2
3-3
4-2
4-3
4-5
5-4
5-7
I. Description & Specifications
The AMPEX Model 601 is a lightweight, portable, magnetic tape
recorder designed for professional use, and is available in any combination of these versions:
Power Input
117 volts, 50 or 60 cycles
per second (cps)
Tape Speed
IY2 or 3 -M inches per
seconds (ips)
Head Assembly
full or half track
An accessory transformer (Catalog N o . 17331-1) featuring convenient,
quick plug-in change from high to low impedance microphone input is
available for use with this model. The machine can be operated in the
horizontal or vertical position. It is packaged in a durable, luggage-type,
saddle-tan Samsonite case, or is obtainable uncased for custom installation.
TABLE 1-1
EQUIPMENT SUPPLIED
UNIT
Complete
Equipment
(in carrying
Case)
Tape Transport
TAPE SPEED
(ips)
7-1/2
7-1/2
7-1/2
7-1/2
3-3/4
3-3/4
3-3/4
3-3/4
7-1/2
7-1/2
7-1/2
7-1/2
3-3/4
3-3/4
3-3/4
3-3/4
7-1/2
3-3/4
Electronic
Assembly
Power Cord
Mating Connector, Microphone Input
TRACK
WIDTH
Half
Full
Half
Full
Half
Full
Half
Full
Half
Full
Half
Full
Half
Full
Half
Full
LINE FREQ AMPEX
(CPS)
CAT. NO.
60
60
50
50
60
60
50
50
60
60
50
50
60
60
50
50
7948-1
7948-2
7948-5
7948-6
7948-101
7948-102
7948-105
7958-106
6200-14
6200-10
6200-15
6200-11
6200-121
6200-122
6200-123
6200-124
17416-1
17416-101
CS-5
DIMENSIONS
(Ins.)
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
16-1/2x13-3/4x8.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
9-5/16x12-1/2x5.
6-1/8x12-1/2x5.
6-1/8x12-1/2x5.
96.
PL-33P
Miniature Phone Plug, Line Input
PL-450
Mating Plug, Output
PL-445
Notes:
1. All mating connectors are supplied without wiring as a convenience
for diversified installation.
2. Hardware kits are available to facilitate maintenance. (See Section VI.)
GENERAL
SPECIFICATIONS
Tape Width
Reel Size
Tape Speed
Playing
Time
Reproduce Timing
Accuracy
Flutter and Wow
Starting
Time
Stopping Time
Fast Forward Time
Rewind Time
Frequency Response
Signal-to-Noise
Record
Ratio
Inputs
VA inch.
7 inch, R E T M A reel ( m a x i m u m ) .
IV2 ips, l u l l track.
IVj ips, half track.
3M ips, full track.
.3M ips, half track.
Full Track—32 minutes w i t i i 7 inch reel,
IV2 ips, 1200 feet.
H a l f Track—64 minutes w i t h 7 inch reel,
71/2 ips, 1200 feet.
± 0 . 2 % , or an accuracy of ± 3 . 6 seconds in
a 30-rninute recording.
71/2 ips—Below 0.17% rms.
ips—Below 0.3% rms.
The tape attains f u l l speed i n less than onefifth second i n either the play or record mode.
Less than one second.
90 seconds for f u l l 1200 foot reel.
90 seconds for f u l l 1200 foot reel.
71/2 ips—40 to 15,000 cps ± 2 db 50 to
10,000 cps down no more than 4 db at 15,000
cps.
3 M i p s — ± 2 db 50 to 7500 cps.
Full Track—over 55 db below peak record level. Peak record level is defined as the
point of 3 % total rms iiarmonic distortion,
measured while using a 400 cps tone; and
peak record level includes bias, erase and reproduce amplifier noise.
H a l f Track—50 db below peak record level.
M I C R O P H O N E : Accommodates any high
impedance microphone, and can be quickly
converted for a low impedance microphone
w i t h the plug-in accessory transformer (Catalog N o . 17331-1).
Reproduce
Operating
Output
Controls
Miscellaneous
The safety button, a flat topped neon lamp,
remains lighted while the machine is in the
record mode.
REWIND—FAST FWD: This selector
switch is mechanically interlocked w i t h the
P L A Y — R E C switch.
1-2
SPECIFICATIONS
The M O N I T O R SELECTOR switch is used
for monitoring as described in the following
paragraphs; but it functions also as an operating control. I n the P L A Y mode, the M O N I T O R selector switch must be i n the T A P E
position i n order to bring the reproduce head
signal to the O U T P U T .
A toggle O N — O F F switch, located on the
control panel, turns power on or off. W h e n
placed i n the O N position, this toggle switch
w i l l cause the capstan to rotate; but the tape
w i l l not move until one of the two operating
switches is turned from its neutral position.
The M I C R O P H O N E input, a three circuit
connector, is conveniently located on the control panel.
The L I N E I N P U T connector is a two circuit
jack recessed into the right side of the equipment.
The O U T P U T connector is a three circuit
jack also recessed into the right side of the
equipment.
M a t i n g connectors are supplied (see
1-1).
Monitoring
1.23 volts rms into 600 ohms at program level.
P L A Y — R E C : The play mode is selected by
placing the switch i n P L A Y position.
The record mode can be selected only by depressing the safety button at the same time
the selector switch is placed in REC position.
LEVEL
The P H O N E S output is a two circuit jack,
located on the front panel.
L I N E : 0.5 volt required for normal program
level.
Reproduce Output
Operating Controls
M I C REC LEVEL, and L I N E REC
are separate m i x i n g controls.
Head Assembly
Power
Requirements
Accessories
Table
The M O N I T O R SELECTOR switch allows
monitoring of program input, or reproduce
output. A phone jack and illuminated v-u
meter are on the front panel.
W h e n the T A P E position is selected, the reproduce output can be monitored.
W h e n the I N P U T position is selected, the
headphones and meter report program signal
level.
Separate erase, record, and reproduce heads
are contained in a single housing.
117 volts, 50 or 60 cps; 0.52
watts.
Maintenance K i t :
Speed Conversion Kits to:
3 M ips, 60 cps
71/2 ips, 60 cps
3 % ips, 50 cps
71/2 ips, 50 cps
ampere,
61
6392-1
7556-0
7556-1
7556-2
7556-3
1-3
SPECIFICATIONS
Accessories
Conversion K i t to:
50 cps operation, 714 ips
60 cps operation, 71/2 ips
50 cp"s operation, 354 ips
60 cps operation, 354 ips
Adaptor for rack mounting
9738
9739
9740
9741
9684-1
Spare parrs kits for:
714 ips, 60 cps machine
7V2 ips, 50 cps machine
354 ips, 60 cps machine
354 ips, 50 cps machine
Minor hardware Kits:
9742-1
9742-2
9742-3
9742-4
7802
See Section V I for a complete parts list.
II. Principles of Operation
If a material capable of being magnetized is placed in the proximity
of a magnetic field, the molecules of the material will be oriented
according to the direction of the field. Any of several methods can be
used to produce the magnetic field, but of most interest in magnetic
recording is that field produced when a current flows through a coil of
wire. The current may be derived from a transducer—for example, a
microphone converting audio sound waves to electric current.
Magnetic Tape
Magnetic recording tape consists of finely divided iron-oxide particles deposited upon a plastic backing. This tape is moved through a
magnetic field in which the magnetizing force is alternating, and the
iron oxide particles are aligned according to the instantaneous direction
and magnitude of the field (See Fig. 2-1).
Fig.
2-1.
Tape
Magnetization
2-1
Magnetic Head
The magnetic field is produced in the gap of a recording head,
over which the recording tape passes. The recording head is a ringshaped electromagnet (See Fig. 2-2). It consists of an incomplete ring
of highly permeable material inserted in a coil of wire. The discontinuity i n the r i n g forms the gap, and the ring is the core of the electromagnet.
GAP
TAPE
e
Fig.
Magnetization Curve
Bias
2-2.
Recording
Head
The magnetization curve of the iron oxide utilized as the recording
medium is similar to that shown as the heavy line in Fig. 2-3. A t points
near the origin, the curve is extremely non-linear, and the signal recorded on the tape would not be directly proportional to the signal applied
to the head. This would result i n a high degree of distortion upon reproduction. This distortion is greatly reduced by the application of a
high-frequency constant amplitude bias signal which is mixed w i t h the
signal being recorded. The frequency of this bias is generally selected
to be five times the upper frequency l i m i t of the recorder to prevent
beating between the bias and harmonics of the recorded signal.
W h i l e the tape is in the recording gap, the bias causes the magnetization characteristics of the iron oxide to follow the dashed line loops
shown i n Fig. 2-3, known as the M I N O R HYSTERESIS LOOPS. As
the tape leaves the gap, the influence of the magnetic field created by
the bias is reduced to zero, and the tape assumes a permanent magnetization, k n o w n as R E M A N E N T I N D U C T I O N , determined by the gap
flux at the time the tape leaves the gap.
After the recording process, there exists on the tape a flux pattern
which is proportional i n magnitude and direction to the signal recorded
on i t . I f the tape is then moved past the gap of a reproduce head—
which is similar in construction to the record head—the magnetic flux
of the m o v i n g tape w i l l induce a voltage in the coil of the reproduce
2-2
Fig.
2-3.
Magnetization
Curve
head. This induced voltage is proportional to the number of turns of
wire on the head, and the rate of change of flux, expressed i n the following equation:
E = N(d0at)
Where E is the induced voltage
N is the number of turns of wire
d0tlt is the rate of change of flux
It is desirable that the gap i n the reproduce head be as small as
possible, so that the gap w i l l intercept less than one wave length of
the signal on the tape at the highest frequency to be reproduced. However, as the gap is made smaller the induced voltage decreases, so there
is a practical l i m i t in decreasing the gap and still maintaining an adequate signal-to-noise ratio.
Induced Voltage
in Head
Induced Voltage
in Head
The voltage induced across rhe head is computed by the following
equation;
E = B
m
TTcj/
V sin
/x
Where E is the induced voltage
B is the maximum flux density of the recording
material
V is the velocity of the tape over the head
w is the gap width
X is the wavelength of the signal on the tape.
In order to provide an overall frequency response that is flat (see
Fig. 2-5) an equalization circuit consisting of a series resistance and
capacitance is inserted in one of the early stages of the reproduce amplifier. This equalizer has a high-frequency droop characteristic (curve B,
Fig. 2-5) which is the inverse of the r e p r o d u c e h e a d characteristic
(curve A , Fig. 2-5). In order to extend the high-frequency response,
additional equalization is included i n the record amplifier in the form
of a high-frequency boost circuit, designed to compensate for the droop
in reproduce head characteristics caused by head core losses, gap losses
and recording losses.
Frequency Response
From this expression it can be seen that the voltage across the coil
increases directly as the velocity increases and as the wave-length decreases (frequency increases). I f rhe tape velocity and gap w i d t h are
assumed to be constant, the output voltage f r o m the head is directly proportional to the frequency, as long as the wave length on the tape is
large compared to the gap w i d t h . This results in an output vs. frequency
characteristic such as shown in curve A of Fig. 2-4. The voltage does
not continue to rise indefinitely. As electrical losses in the core material increase, and as the wave-length on the tape approaches the same
dimensions as the reproduce head gap, rhe actual output resembles curve
B of Fig. 2-4.
OUTPUT
(db)
1
(
1
J ^ _ _ .
1
1
1
1
+ 25
+ 20
Fig.
2-5.
Achieving
Flat
Response
A !/
1- +
+ 15
1
+10
t
+5
1 B
0
—
-5
-10
-15
-20
-25
10
100
1000
lOKC
FREQUENCY
Vig. 2-4.
Output vs.
Frequency
2-5
2-4
III. Installation a n d
Operation
This machine can be operated i n either the horizontal or vertical
position. I n the carrying case, installation consists only of making up
and connecting the required cables (See "Connector" in this section).
For studio installations, an adaptor (Catalog N o . 9684-1) is available
which permits mounting i n a standard 19-inch relay rack.
GENERAL
The power requirements are 117 volt a-c, 50 or 60 cps, 0.52 ampere,
61 watts. A name plate on the bottom of the case adjacent to the aperture for O U T P U T , L I N E I N P U T and 117 v. a-c indicates the proper
line frequency.
POWER
The line input is an unbalanced bridging input of 100,000 ohms.
Any unit connected to the L I N E I N P U T connector should deliver a signal of at least 0.5 volt when recording f r o m consolettes, mixers or other
tape recorders.
LINE INPUT
The recorder is wired for a high impedance microphone, but provision for internal mounting of an accessory plug-in transformer immediately changes the machine for use w i t h low impedance microphones.
T o make this conversion, remove the four screws on the panel of the
electronics assembly. The panel and assembly can then be removed.
MICROPHONE
A.
B.
C.
INPUT
High
Impedance- -a dummy plug J107P shown on the schematic diagram (Fig. 5..5) must be plugged
into socket J106S for high impedance operation.
Low Impedance — remove the dummy plug J107P. Accessory transformer A M P E X catalog number
173.51-1 (shown as T103 on schematic diagram Fig. 5.3) is then plugged into J106S
for impedance i n the range of 150 ohms
to 250 ohms.
30 o h m to 50 ohm — Install transformer T103 as shown on
the schematic diagram ( F i g . 5.3) by plugg i n g the transformer into socket J106, and
removing the jumper as shown i n Note 7
on the schematic.
The output of the machine should be connected to a unit having 600
ohms input impedance. I n a situation wherein the recorder w i l l work
into a high impedance line, physically terminate the O U T P U T connector w i t h a 600 o h m resistor and bridge this resistor w i t h the high i m pedance circuit. A three circuit O U T P U T plug is supplied. A t w o circuit
plug can be used, and w i l l w o r k ; but it automatically makes an unbalanced line. I f an A M P E X amplifier loudspeaker is used p l u g i t into the
M O N I T O R jack only.
REPRODUCE
OUTPUT
INTERCONNECTING
Regardless of application observe the requirements under "Line I n p u t "
and "Reproduce O u t p u t " when interconnecting the machine w i t h any
other piece of equipment.
CONNECTORS
A power cable and matching plugs for the M I C R O P H O N E ( J I O I S ) ,
L I N E I N P U T (J102S), and O U T P U T (J104S) connectors are supplied w i t h the equipment.
Shielded, low-capacity cable is recommended for making up input
and output cables. Make such cables as short as possible for interconnecting units in audio systems. Refer to the schematic diagram (Fig.
5.3), to determine correct p i n connection for all plugs.
The tape threading path described below is the same for all modes
of operation; but special attention is called to the notes dealing w i t h
half track heads.
Step 1 : Place a reel of tape on the left-hand turntable, and an empty
reel on the right-hand turntable, making certain that the pins
around the base of each spindle engage corresponding slots on
the reel hubs.
Step 2:
Press a reel hold-down knob i n place on each spindle.
Step 3:
Thread the tape as indicated i n the frontispiece. Make sure
the oxide or dull surface is against the heads.
Step 4 :
Anchor the tape in the slot on the empty reel hub if desired,
but a f u l l tape turn counterclockwise around the reel hub is
usually sufficient.
REEL
HOLD-DOWN
SUPPLY
STUDIO
INSTALLATION
•'
TAKEUP
The reproduce head cable is double shielded, insuring against r-f
pickup. Cable capacity and length have been minimized to avoid high
frequency loss. I n general, mount the electronic assembly and tape transport no more than one foot apart. I f the reproduce head cable is lengthened for greater separation of the components, high frequency response
w i l l be affected. In the event an installation absolutely demands lengthening this cable, a very low capacity type (RG-62/U) is indicated, plus
the addition of an outer shield. H i g h frequency losses cannot be kept
to a m i n i m u m i f the cable length exceeds three feet.
Space requirements for custom installation are given in the accompanying illustration ( F i g . 3-1). A l l o w sufficient clearance at the right
side of the electronics chassis for easy access to L I N E I N P U T and O U T P U T connectors. I f desired, these connectors can be brought to a patch
panel mounted at some more convenient point i n the installation to provide ready accessibility.
MICROPHONL
RECORD
LEVEL
Fig. 3-2.
MnNllLP
SELECTOR
LINE
RECORD
LEVEL
Tape Threading
MICROPHONE
INPUT
and
Nomenclature
NOTE
Fig. 3-1.
3-2
Space
Requirements
Because machines using half track heads
record or reproduce only half the tape w i d t h ,
the tape supply must be so oriented that the
half to be recorded is farthest from the tape
transport surface. A f t e r the entire tape has
been wound onto the take-up reel f r o m a recording run, for instance, the take-up reel
must be turned over and the second half recorded—or indentified for a later run. For
example:
TAPE THREADING
,
RECORDING
HALF TRACK
Step 1:
Step 2:
Step 3:
Step 4:
Step 5:
Step 6:
Thread a tape as directed under "Tape Threading."
Set the machine as indicated in "Recording," immediately following.
The entire tape must be reeled onto the take-up reel, regardless
of whether or not the recording is completed. F A S T — F W D
can be used if program material does not use the entire tape.
Remove the take-up reel f r o m the machine and turn it over.
Remove the turntable reel which is now free of tape.
Place the take-up reel on the turntable side.
Reversing the take-up reel after a recording run, places the tape in the
only position for proper threading from the turntable side; and also
orients the still unrecorded half of the tape so that it is farthest from the
tape transport. If the tape had been rewound, the second run would
have erased the previous recording.
REPRODUCING
UAic
TDArir
HALF TRACK
Refer to the steps in "Reproduce," following. The half track tape w i l l
reproduce correctly only if oriented so that the half of the tape desired
• r
i
r
i
c
IS farthest from the tape transport surface.
In reproduce mode, after the entire tape has been reeled onto the take-up
reel, reverse the reel and place it on the turntable side.
RECORDING
Previously recorded tapes are erased automatically as new recordings
are made, eliminating the need for an erasure run because the tapes
first pass over the erase head whenever the machine is recording; but
for the finest recording, it is recommended that the tapes be tank erased.
Connect the program source equipment (microphone, mixers,
etc.) to the appropriate input.
Step 2: Place the M O N I T O R SELECTOR switch on the I N P U T
function.
Step 3: Place the O N - O F F toggle in the O N position.
Step 4: Adjust either the M I C REC LEVEL or the L I N E REC LEVEL
control, depending on whether the M I C R O P H O N E input or
the L I N E I N P U T is being used, so that on the most intense
volume peaks of the program to be recorded, the v-u meter
needle swings to approximately zero on the v-u scale. I t is
unnecessary to start the tape motion i n order to set the program level. I f only one input is being used, turn the other
REC LEVEL to zero.
Step 5: Place the P L A Y - R E C control in the REC position by depressing the safety button at the same time the record position is
selected. The transparent plastic button glows while the machine is in the record mode. This record safety feature prevents
accidental erasure of previously recorded tapes. W h e n returning to the P L A Y or the neutral position at the dot, the safety
button is not used.
W h i l e recording, a continuous comparison of the incoming program
and the reproduction on the tape can be effected by turning the M O N I T O R SELECTOR switch back and forth between the I N P U T and
T A P E positions and observing the v-u meter, or using headphones.
Step 1:
3-4
T o stop recording, return the P L A Y — R E C control to neutral, marked
by a dot.
Step
Step
Step
Step
1:
2:
3:
4:
Step 5:
Thread a previously recorded tape on the machine.
Place the O N — O F F toggle i n the O N position.
Place the P L A Y — R E C control i n the P L A Y position.
Place the M O N I T O R SELECTOR switch i n the T A P E position.
Adjust the reproduce level through the volume control of the
program source.
If there is no output, check the M O N I T O R SELECTOR
switch position. W h e n the machine is i n the play mode,
the M O N I T O R SELECTOR switch must be i n the T A P E
position. O U T P U T can be monitored w i t h the headphones
plugged into the jack on the front panel.
T o rewind or move tape forward rapidly, place R E W I N D — FAST
F W D switch in the position desired. The tape moves at 800 feet per
minute in either direction, and can be shuttled back and forth between
R E W I N D and FAST F W D positions without waiting for the tape to
decelerate or stop. Thus, cueing and editing can be accomplished at
high speed w i t h no danger of tape breakage.
RECORDING
REPRODUCING
REWIND A N D
FAST FORWARD
The R E W I N D — F A S T F W D and P L A Y - R E C controls are mechanically interlocked, making impossible the switching of either control
unless the other is i n neutral. This safety feature guards against tape
breakage which would occur if the machine were switched directly f r o m
either of the high speed modes to P L A Y or REC position.
CAUTION
Always return R E W I N D — F A S T E W D control to neutral
position, and wait til tape motion stops before switching to
P L A Y or REC. Placing selector controls on P L A Y or REC
while tape is in motion w i l l cause stretched or broken tape.
T o erase a previously recorded tape when no new reproduction is desired, t u r n both of the REC LEVEL controls to zero and r u n the tape
in the record mode.
ERASE
Because microphone and line recording channels are independent, each
governed by its own level control, simultaneous recording f r o m two
sources can be made without an external mixer.
MIXING
For example, singing, voice announcements or instrumental accompaniment can be dubbed into a program being recorded f r o m a consolette or other tape recorder. T o effect this, connect the program source
equipment to the L I N E I N P U T connector and a microphone to the
M I C R O P H O N E connector. Adjust both the M I C R O P H O N E REC
L E V E L and L I N E REC L E V E L controls for desired balance between
the t w o programs.
3-5
SYNTHETIC
REVERBERATION
Special effects, similar to those obtained through the use o f an echo
chamber can be created easily.
Connect a microphone and set the program level as usual; then connect
the O U T P U T connector to the L I N E I N P U T connector, t u r n the
M O N I T O R SELECTOR switch to T A P E , and start recording. The reverberation decay rate, which is the time required for the echo to die
away, can be varied w i t h the L I N E REC L E V E L control. The Control
value chosen w i l l depend entirely on the effect desired. I f the control is
set too high, continuous oscillation w i l l result, and the v-u meter needle
w i l l swing to m a x i m u m and remain there. I f this happens, adjust to a
lower setting.
IV. Tape Transport Assembly
The tape transport mechanism incorporates a single-speed synchronous
motor and a system of pulleys, belts, and clutches to drive the capstan
and the turntables. Three modes of tape motion ( P L A Y , R E W I N D ,
and EAST F O R W A R D ) are determined by t w o controls located o n
the top panel of the tape transport. (The neutral position for each control is marked by a dot.)
The bracketed numbers i n this section refer to parts shown i n Fig. 4-1,
Fig. 4-4, and i n the parts list at the end of this manual. For greatest
facility i n following the discussion below, i t is suggested that Fig. 4-4
be opened fully for ready reference.
GENERAL
Power is applied to the drivemotor ( 6 3 ) when the P O W E R switch on
the front panel of the electronic assembly is turned to the O N position.
The capstan ( 4 2 ) begins to rotate immediately, being driven by a
nylon belt ( 6 8 ) which runs between the motor pulley ( 6 1 ) and the
capstan flywheel. A second belt ( 6 9 ) running i n a groove in the capstan flywheel drives the play takeup pulley ( 4 0 ) . The shock relief
brake rollers ( 2 ) are engaged against the rubber-tired fast forward and
rewind clutches ( 1 6 and 3 1 ) . Both turntables are motionless, and the
machine is i n standby condition.
STANDBY
OPERATIC
Since the capstan is i n motion when the machine is in the standby condition, the tape w i l l accelerate to full play speed almost instantly when
the P L A Y switch is operated, thus producing a wow-free start.
W h e n the P L A Y control is energized the following mechanical sequence occurs:
1) The play takeup pulley ( 4 0 ) and belt ( 6 9 ) are brought to bear on
the play takeup clutch ( 1 9 ) .
2 ) The shock relief brake roller ( 2 ) on the play takeup side is released from the fast forward clutch tire ( 1 6 ) .
3) The capstan idler ( 7 9 ) engages the capstan ( 4 2 ) , which drives
the tape, pulling i t from the tape supply turntable (i.e. the rewind
turntable) and feeding i t to the takeup turntable, which now begins to rotate. I t is especially important to understand that when
the machine is operating normally in the play mode, i n which the
tape is clamped against the capstan by the capstan idler, the turntables are effectively isolated from each other. The takeup turntable, as its name implies, does nothing more than take up the tape
fed to i t by the capstan. I t does not p u l l the tape from the tape
supply turntable.
4 ) The shock relief brake roller ( 2 ) on the rewind side remains engaged against the rewind clutch tire ( 3 1 ) , and slippage occurs
between the clutch and disc assembly ( 3 0 ) . The friction produced
i n this slippage, and the friction produced by the rewind holdback
brake ( 3 7 ) operating o n the bakelite drum ( 3 5 ) provide the required holdback tension.
3-6
PLAY MODE
4-1
The R E W I N D - F A S T F O R W A R D control cannot be operated unless
the P L A Y control is in neutral. W h e n the R E W I N D - F A S T FORW A R D control is turned to R E W I N D :
1) Both shock relief brake rollers (2 ) are released.
2) The rewind idler ( 7 ) is clamped between the motor pulley ( 6 1 )
and the rewind clutch tire ( 3 1 ) and the rewind turntable is
driven.
3) Holdback tension is provided by the holdback brake ( 2 5 ) on the
takeup assembly as tape is pulled from the takeup turntable.
REWIND MODE
W h e n the R E W I N D - F A S T F O R W A R D control is turned to FASTFORWARD:
1) Both shock relief brake rollers ( 2 ) are released.
2) The rubber-tired fast forward clutch ( I 6 ) is brought to bear on
the motor pulley ( 6 1 ) and drives the takeup turntable.
3) Holdback tension is produced by the holdback brake ( 3 7 ) on the
rewind assembly.
FAST FORWARD
OBIVEMOTOR
©
0
©
©
@
©
®
SHOCK
R E L I E F BRAKE
REWIND IDLER
FAST
FORWARD
PLAY
TAKEUP
HOLDBACK
REWIND
,
CLUTCH
CLUTCH
BRAKE
CLUTCH
HOLDBACK
BRAKE DRUM
©
©
©
©
©
©
Fig. 4-1. Mechanical Operation
(0 PPER
RE ARING )
HOLDBACK BRAKE
PLAY
TAKEUP P U L L E Y
CAPSTAN FLYWHEEL
MOTOR P U L L E Y
NYLON
DRIVE BELT
TAKEUP
CAPSTAN
BELT
IDLER
Simplified
Vig. 4-2. Routine
4-2
Lubrication
MODE
ROUTINE
MAINTENANCE
Cleaning
Lubrication
Routine maintenance of the tape transport mechanism
marily of periodic cleaning and lubrication.
consists p r i -
Cleanliness of all parts of the tape drive mechanism is required for consistent o p t i m u m performance. Most tape manufacturers lubricate their
tapes; this lubricant w i l l gradually f o r m a coating on the head assembly
and the idler wheels and may cause loss of positive drive at the capstan.
Therefore, periodic cleaning of both the head assembly and all parts of
the tape drive mechanism is particularly important. The recommended
agent for cleaning Ampex Head Assemblies is a mixture of Xylene and
0 . 1 % Aerosol. This agent is available i n 2 0 2 . bottles. ( A m p e x Catalog
N o . FP-7.) T o clean any head assembly simply w i n d a clean, lintless
cloth on a swab-stick and moisten w i t h this mixture. Swab the heads
periodically to remove all dirt and oxide which may have accumulated
f r o m the tape. Clean all parts except the head assembly w i t h a clean,
lintless cloth moistened w i t h denatured alcohol.
CAUTION
D o not use any other solvents as there are some which may damage the
adhesive used to hold the head laminations together.
The o i l hole is located in the bearing housing as shown in Fig. 4-2.
Use exactly four drops of oil—no more.
D o not o i l any other parts of the tape transport mechanism. A l l other
bearings and moving parts are lubricated for life.
It may be said in general, that most of the difficulties that w i l l normally
be encountered in the Model 601 tape transport mechanism w i l l be
traceable to contamination of belts, pulleys, bearings, and other friction
surfaces, whether due to carelessness in routine lubrication, or to the
gradual accumulation of dirt and other foreign material to be expected
over a reasonable length of time. Correction of these difficulties w i l l
usually be a matter of careful disas.sembly and cleaning, rather than readjustment of the mechanism. The normal torques (and hence, tape
tension) i n this mechanism are, in fact, fixed w i t h i n strict design specifications, and are not adjustable. The measurement of these torques w i l l
frequently provide a rapid means for isolating the source of mechanical
troubles.
I
The recommended standard lubricant for the four places which require periodic lubrication (motor and capstan) is Caloil N o . OC-11.
This lubricant is available f r o m A M P E X as Stock No. 70-9
(V2 oz.
oiler) or FP-5 ( 4 0 2 . )
Z"W—SEE
I
Mechanical
Troubleshooting
NOTE
NOTE
The proper lubricant is available f r o m A M P E X as Stock No.
70-9
(1/2 oz. oiler) or PP-5 ( 4 o z . ) .
The upper and lower bearings of the drive motor should be lubricated
after every 500 hours of operation. The upper o i l hole of the motor is
accessible through a hole i n the tape transport grille slightly above and
to the left of the takeup turntable. For access to the lower o i l hole, located i n the side of the motor end bell, remove the tape transport f r o m
the case (See Fig. 4 - 2 ) .
Four or five drops of one of the recommended lubricants is sufficient.
Care should be taken to avoid over-oiling or spills. A n y such excess
should be wiped away w i t h solvent.
The capstan may require oiling about once for every four oilings of the
drive motor. For access to the upper bearing, the capstan idler must
first be removed (See Fig. 4-2). Remove the rubber cap on the idler.
Remove the hairpin retainer and l i f t the idler off its shaft, taking care
not to lose the washers associated w i t h i t . The aluminum plug-bottom
over the capstan shaft may now be pried off and the felt washer beneath
it removed to expose the upper capstan bearing. Use as much of one
of the recommended lubricants as the bearing w i l l accept, wipe away
any excess, and reassemble.
CAU7I0N
D o not o i l the felt washer which serves only as a dust protector and
to keep o i l from working its way up the capstan.
For access to the lower bearing, remove the tape transport f r o m the case.
4-4
HOLDBACK
5
3/4- B
3/4
HOLOaACK
2 - 3
OZ,-IN.
1/2
OZTIN,
5 - 7
OZ.-
IH.
V4-[
1/4
OZ.-IPt.
TAKEUP
3 / 4 - 1 1/4 O Z - I N
5 - 7
F A S T
02.-
IN.
FOHWARD
NOTES:
1.
I F REEL
SPRING
2.
PULL
ALLOW
TAKE
HUB
DIAMETER
SCALE
SCALE
SCALE
WITH
TO
LARGER
BY
STEADY
MOVE
ALL READINGS
Fig.
IS
BEADING
4-3.
IN
WHILE
HUB
OR
SMALLER
RADIUS
TO
THAN
OBTAIN
MOTION
WHEN
TOWARD
REEL
WHEN
SCALE
IS
MOTION.
IN
Tape Tension
MEASURING
2
INCHES,
OZ.—IN.
HOLDBACK
MEASURtNS
MUUTIPLY
READING ,
rENStONS.
TAKEOP
TENSIONS.
Measurements
4-5
Torques a n d
Tape Tension
The measurement of torques on the Model 601 requires the following
equipment:
1)
A light-movement spring scale (e.g. Post-A-Let, 0 to 8 oz,, Exact
W e i g h t Scale Co., Columbus, Ohio.
2 ) A measuring hub. A standard R E T M A plastic reel may be used. I f
the hub diameter is exactly 2 inches, the spring scale w i l l read
directly i n ounce-inches. Reels w i t h smaller hubs can be brought
up to 2-inch diameter by w i n d i n g on sufficient tape. I f a reel of
greater than 2-inch hub diameter is used, multiply the spring scale
reading by the hub radius to obtain the ounce-inch reading.
3) A piece of string, approximately 30 inches long, w i t h a small loop
tied at one end.
Torques measured on the driven turntable in any mode, (i.e. the turntable on which the tape is being wound) are a measure of takeup tension. Torques measured on the turntable f r o m which the tape is pulled
in any mode are a measure of holdback tension (See Fig. 4 - 3 ) .
•
Takeup
Tension
Step
Step
Step
Holdback Tension
Malfunctions
in Play Mode
4-6
Place the measuring hub on the driven turntable.
W i n d a few turns of string around the hub in the direction of
normal tape wrap, and attacli the spring scale to the loop at
the end.
3: Start the machine in the appropriate mode and, as the string
,is wound on the hub, allow the scale to move in w i t h it, tak„ing the reading while the scale is in motion. Normal torques
are as follows:
Fast Forward
5 to 7
oz-in.
Rewind
5 to 7
oz-in.
Play
2 to 3V2 oz-in.
1:
2:
Place the measuring hub on the turntable from which the tape
is pulled in the mode in operation.
Step 2: W i n d the string on fully in the direction of normal tape wrap,
and attach the spring scale.
Step 3: Start the machine in the oppropriate mode, and pull the scale
slowly i n the direction in which tape is normally pulled from
this reel, taking the reading while the scale is in steady motion. N o r m a l torques are as follows:
Fast Forward
->4 to U/i oz-in.
Rewind
% to 1(4 oz-in.
Play
5 % to 8 4 oz-in.
These values listed above for both takeup and holdback tensions may
be close to the lower l i m i t when the machine is new, and w i l l usually
move up toward tlie upper limit after the first 10 or 12 hours of operation.
The word "contaminated," as used here, may indicate either the presence of o i l where it is not wanted, or accumulations of dirt and other
foreign matter on pulleys and belt. In either case, carbon tetrachloride
is recommended as the cleaning agent. After cleaning a contaminated
part, clean any other part w i t h which it normally comes into contact
whether or not that part shows any immediate evidence of contamination. Bracketed numbers refer to parts shown in the exploded view of
the mechanical assembly. Fig. 4-4, which should serve as a guide for
any necessary disa.ssembly and reassembly.
Rewind and fast forward malfunctions w i l l usually be reflected as an
apparent loss of power in those modes, loose tape w i n d , erratic tape motion or slippage, and, possibly no rewind or fast forward at all. The first
step is to make a quick check of rewind or fast forward takeup and
holdback tensions as described previously. The malfunctions discussed
below apply to either mode, the turntables, associated components, and
tape directions being opposite of each other.
Starting, stopping, and shuttling malfunctions w i l l be evidenced by the
throwing of tape loops and, in extreme cases, by tape breakage. These
troubles are usually associated w i t h low takeup tension of brake malfunctions produced primarily by tampering or misassembly, or contamination due to careless oiling or accumulation of dirt.
The following section covers some adjustments, critical clearances, and
alignment which must be maintained in reassembling parts of the tape
transport mechanism that may have been disassembled for servicing.
T w o general precautions should be observed i n any required disassembly:
1)
Step 1:
Nearly all malfunctions in the play mode w i l l be reflected as flutter and
wow in excess of specifications. A quick check of takeup and holdback
tensions, discus.sed in the previous section, may lead directly to the
source of trouble. Possible causes of flutter and wow are suggested in
the following check list.
2)
Malfunctions
in Play Mode
Malfunctions in
Rewind or Fast
Forward Mode
Starting, Stopping
a n d Shuttling
Malfunctions
Assembly and
Construction Notes
Always note the number, type, and location of washers i n an assembly very carefully. Should washers, retainers or other small hardware be lost or damaged i n servicing, a k i t containing an assortment
of such hardware ( A m p e x Catalog N o . 7802) is available through
your dealer.
T o remove the sub-plate ( 1 ) , a preliminary to any further disassembly of parts under the top plate casting, remove only the three
elastic stop-nuts that hold i t , and clevis p i n that links the slide lever
( 1 3 ) to the lower yoke of the rewind/fast forward actuator ( 4 8 ) .
It is unnecessary to remove the adjustment screws (70 and 71) for
the capstan thrust and the motor thrust. I f the settings of these
screws are changed, they must be carefully readjusted as described
in the following subsections. The thrust discs ( 6 5 ) beneath these
screws, being coated w i t h grease, w i l l usually stay in place when
the sub-plate is removed. It is advisable, however, to be sure that
they do not fall out. I t w i l l generally be found easiest to re-install
the sub-plate after servicing, if the P L A Y control is energized.
The tape transport incorporates rubber shock mounts on the screws retaining the motor mounting plate to the top plate casting. These shock
mounts provide automatic centering of the drivemotor and no adjustments are necessary.
The drivemotor thrust is a hardened steel ball ( 6 0 )
against a nylon
Drivemotor Thrust
4-7
Drivemotor Thrust
disc ( 6 5 ) . The capstan thrust is adjusted by a set-screw ( 7 0 ) . End play
of .010 in. to .015 in. is required, and is obtained as follows:
Step 1: Coat the nylon thrust disc liberally w i t h wheel bearing grease
and drop it through the threaded hole i n the sub-plate ( 1 )
over the capstan shaft.
Step 2:
Insert the set-screw, and tighten down until it is felt to bottom on the thrust disc.
Step 3:
Grasp the capstan flywheel ( 4 2 ) between the thumb and i n dex finger.
Step 4:
Step 5:
4-8
W h i l e maintaining a slight downward pressure on the head
of the set-screw w i t h the screwdriver ( t o simulate the pressure
that w i l l later be applied by the locking screw) start backing
the screw off slowly, and work the capstan flywheel up and
down u n t i l an audible click at the ends of its travel indicates
the presence of end play. This w i l l usually occur when the setscrew has been backed off approximately 14 of a turn. A t this
point, end play should be in the required range.
Tighten the locking nut on the set screw, then recheck end
play.
Turntable Height
Turntable height (the distance measured f r o m rhe top surface of the
turntable ( 7 8 ) to the perforated metal g r i l l e ) should be .125 in., ± . 0 0 8
in. This height is determined by the replacement of lamicoid washers
betwen the bottom of the turntable pivot (24 or 36) and the hairpin
retainer on the shaft through the pivot. Difficulties in tape tracking
traced to improper turntable height may be corrected by increasing or
decreasing rhe number or thickness of these washers.
Play Takeup Clutch
The play takeup clutch assembly consists of a felt-lined aluminum disc
( 1 8 ) , and a bakelite clutch (19) which is spring-loaded to the disc.
W h e n the machine is in the play mode, the clutch is driven by the rubber belt (69) on the play takeup pulley ( 4 0 ) . Location of the felt-lined
aluminum disc is critical—a clearance of .015 in. being required between the end of the oilite bearing ( 2 1 ) which goes through the bakelite clutch ( 1 9 ) , and the bottom of the aluminum disc ( 1 8 ) . This clearance, which cannot be measured directly w i t h a gauge because of the
physical arrangement can be set quite accurately by the f o l l o w i n g i n d i r e a method:
Step 1: Insert a removable .015 in. shim or feeler gauge between the
thrust washer that rides on the inner race of the lower ball
bearing ( 2 2 ) of the takeup turntable pivot ( 2 4 ) and oilite
bushing ( 2 1 ) .
Step 2:
Assemble the conical spring ( 2 0 ) , the bakelite clutch ( 1 9 ) ,
and the felt-lined aluminum disc ( 1 8 ) ( i n that order) on the
turntable shaft ( 2 9 ) .
Step 3: Guide the end of the oilite bushing through the hole in the
center of the bakelite clutch, and press the aluminum disc
down u n t i l it bottoms firmly on the end of the bushing.
Step 4: H o l d i n g the disc plate in place, tighten the set screw in its
hub.
Step 5: Remove the shim or gauge. The expansion of the conical
spring w i l l then force the oilite bushing back oflf the aluminum disc, thus creating the required .015 in. clearance.
The rubber-tired bakelite rewind ( 3 1 ) and fast forward clutches must
line up w i t h the shock relief brake rollers ( 5) so that the rollers engage
the f u l l w i d t h of the tires. I n addition, the rewind clutch ( 3 1 ) should
be aligned for f u l l - w i d t h contact w i t h the rewind idler ( 7 ) and the fast
forward clutch ( 1 6 ) for full w i d t h contact w i t h the motor pulley ( 6 1 ) .
The capstan speed w i l l not vary, since the capstan is driven by a nonslipping nylon belt and synchronous motor. N o adjustment of the capstan speed w i l l be necessary. I f it is desired to check the capstan speed,
use a pre-recorded 5000 cycle tape, that has been recorded on a machine
of known accuracy, and an electronic frequency counter.
Troubleshooting
Trouble
EXCESSIVE
HOLDBACK
EXCESSIVE
TENSION
OR
ERRATIC
TENSION
TAKEUP
DRIVEMOTOR
OUT
OE
SYNCHRONISM
Rewind and
Fast Forward
Clutch Alignment
Capstan Speed
TABLE
PLAY
4-1
Model
Malfunctions
Probable Cause
1. Contaminated rewind clutch felt
(.30).
2. Contaminated rewind clutch tire
(31).
too
3. Rewind clutch spring ( 3 2 )
stiff. This actually indicates tampering or carelessness in reasembly.
It is advisable to replace the spring
rather than to attempt makeshift
readjustment.
1. Contaminated play takeup clutch
felt ( 1 8 ) .
2. Oilite bearing ( 2 1 ) bottoming on
aluminum clutch disc ( 1 8 ) . M i n i m u m clearance should be .015".
See sub-paragraph 8.4 below for
adjustment procedure.
3. Takeup clutch spring (20) too
stiff.
1. Line voltage below 105 volts a-c.
2. Excessive play takeup tension. See
trouble above.
3. N y l o n drive belt ( 6 8 ) tension excessive. See sub-paragraph 8.1 below.
4. Belt tensioning idler ( 5 5 ) dragging.
5. Drivemotor thrust misadjusted. See
subparagraph 8.2 below.
6. Defective drivemotor starting capacitor.
7. D r y bearings in drivemotor ( 6 3 ) ,
capstan ( 4 2 ) , or capstan idler (79).
See lubrication instructions.
8. Defective drivemotor ( 6 3 ) .
4-9
FLATTED
CAPSTAN
OR DENTED
IDLER
TIRE
DEFECTIVE
OR IMPROPERLY
INSTALLED
NYLON DRIVE BELT (68)
If the capstan idler (79) is left engaged over an extended period
when the machine is not operating,
the idler tire may become dented.
If running the machine in the play
mode for several hours does not restore the tire to normal, the idler
must be replaced.
Belt spliced improperly.
Belt installed with splice joint
toward pulley.
Belt worn because misaligned motor pulley (61) causes the belt to
track against one of the capstan
pulley flanges (42).
1, Contaminated rewind idler guide
(8).
TABLE
Troubleshooting Starting, Stopping, and Shuttling Malfunctions
Trouble
TAPE LOOP
THROWN
ON STARTING
IN PLAY
MODE (LOW PLAY
TAKEUP
TENSION)
REWIND IDLER (7) NOT
DISENGAGING
FROM
MOTOR PULLEY
(61)
REELS MISALIGNED
WITH 1. This will usually cause tape scrape
which may or may not be audible
RESPECT TO TAPE
GUIDES
but will generally appear as flutter.
See subparagraph 8.4 below.
TABLE
Troubleshooting REWIND
Trouble
TAKEUP
TENSION
LOW
EXCESSIVE
HOLDBACK
TENSION
4-2
and FAST FORWARD
Mode Malfunctions
Probable Cause
Clutch leaf spring (17 and 32) too
weak, usually caused by tampering. Replace. Never attempt to increase rewind takeup tension to offset other
problems.
1. Contaminated holdback wipes (25
or 37).
2. Bakelite drum (23 or 35) on which
wipe operates has been roughened.
Evidence of bent or misassembled parts.
Check exploded view, Fig. 4-4.
BRAKE SHOCK
RELIEF
ROLLER (2) NOT RELEASING FROM
FAST
FORWARD
CLUTCH
(16)
Bind in idler guide (8) caused by conREWIND IDLER (7) NOT
tamination.
ENGAGING
MOTOR
PULLEY (61) BIND IN
REWIND IDLER
BEARING
(PART OF 7)
MALFUNCTIONING
Bind in turntable centering detent
TURNTABLE
PIVOTS
(77).
(24 or 36)
4-3
TAPE LOOP
THROWN
ON STOPPING OR
SHUTTLING
Probable Cause
Play takeup belt (69) contaminated.
Nylon drive belt (68) contaminated. If either the play takeup belt
or the nylon drive belt is contaminated with oil, an overoiled motor
or capstan is indicated. Clean all
affected parts thoroughly with carbon tetrachloride.
Slippage between play takeup belt
(69) and clutch (19) due either
to weak play takeup arm spring
(41) or bind in play takeup pulley
bearing (part of 40).
Bind in turntable shaft bearings
(22 or 24) due to contamination.
Clean and lubricate with two or
three drops of medium weight oil.
Play takeup brake release (14) inoperative due to bind, weak or unattached spring (11) causing shock
relief roller (2) to drag on fast
forward clutch tire (16).
One or both brake shock relief actuators (2) binding.
One or both brake shock relief
springs (12) off. End loops on
these springs must be fully closed
to prevent their becoming disconnected.
3. Bind in turntable centering detent
(77).
V. Electronic Assembly
The electronic assembly consists of a record channel, a reproduce channel, a bias and erase oscillator, and a power supply, mounted on a single
chassis.
The record channel consists of a two-stage microphone preamplifier
V l O l and V 1 0 2 A and a three-stage amplifier, V102B, V103A, V 1 0 3 B
(Fig. 5.3).
GENERAL
RECORD CHANNEL
W h e n dummy plug J107P is inserted in receptacle J106S i n the microphone preamplifier, the microphone input matches a high impedance
microphone. A plug-in transformer, available as accessory equipment,
w i l l provide the proper match for a low impedance microphone.
The M I C R O P H O N E input JIOIS and L I N E I N P U T J102S have separate controls R106 and R125 respectively. Both inputs can be used
simultaneously. M i x i n g takes place in the first stage of the record amplifier, V102B. Signals i n the record channel are picked off the RECO R D C A L I B R A T I O N potentiometer R114 at the output of this stage,
and can be switched to the output amplifier through the M O N I T O R
SELECTOR switch SI02, for monitoring.
Record equalization, accomplished i n the g r i d circuit of V103A, and
the cathode circuit of V103B, is adjusted by trimmer C107. Plate voltage is supplied to the last stage of the record amplifier, V103B only
when switch S201 on the tape transport is in the REC position.
The reproduce channel consists of a two-stage reproduce amplifier,
V104, V105 and a two-stage output amplifier V 1 0 6 A and V106B.
The signal from the reproduce head appears at connector PIOIP. Reproduce equalization is provided by C I 16 and R130. Level is adjusted
by potentiometer R137.
REPRODUCE C H A N N E
The reproduce signal is fed to the output amplifier through the M O N I T O R SELECTOR switch when it is in tape position. The output amplifier consists of one voltage amplification stage V 1 0 6 A , and a cathode
follower output stage V106B, which is transformer-coupled to O U T P U T connector J104S. A v-u meter and resistor shunt this connector.
The bias and erase oscillator is an LC push-pull oscillator operating at
approximately 100 kc. The NOISE B A L A N C E potentiometer R147
common to both grids of the oscillator is adjusted to eliminate any
asymmetry in wave f o r m . Lack of wave symmetry would introduce a
d-c current in the record head, causing permanent magnetization and a
resultant distorted signal. Bias level is adjusted by trimmer C113. The
oscillator, dependent on plate voltage, operates only when switch S201
is i n the REC position.
BIAS AND ERASE
OSCILLATOR
5-1
BIAS AND ERASE
OSCILLATOR
ELECTRONIC
ALIGNMENT
ALIGNMENT AND
TEST EQUIPMENT
REQUIREMENTS
Head
Demagnetization
Demagnetization
Alignment consists i n making all necessary adjustments for proper
electronic performance. A recorder out of alignment may be characterized by poor frequency response, high noise, low output, high distortion,
or a combination of these faults. A l l Ampex recorders are completely
aligned at the factory, and no adjustments should be necessary. The
overall performance checks outlined i n Section 3 w i l l generally serve
to determine i f realignment is necessary at any time.
Alignment can be accomplished without removing the electronic assembly f r o m the case. I f desired the electronic assembly can be w i t h drawn by removing the four screws on the front panel. Stand the case
in a vertical position and pull the electronic assembly forward. The
interconnecting cables between the electronic assembly and the tape
transport are sufficiently long for access to all adjustments while the
units are connected.
The following equipment is required for proper alignment and testing:
A. Audio Oscillator—Hewlett-Packard
Model 200C or equivalent.
B. Vacuum Tube Voltmeter—Hewlett-Packard
Model 400C or
equivalent.
C. Ampex Alignment Tape—Catalog
N o . 5563. This tape is recorded at IV2 ips 10 db below normal operating level as
defined i n Section 3. The tape contains voice announcements
of the following tone sequence: reproduce head alignment
tone, reference tone for reproduce level adjustment, tone
series for reproduce response check.
D . Ampex Head Demagnetizer—Catalog N o . 704.
E. High Impedance Headphones
F. Small Screwdriver
Demagnetize the record and reproduce heads before aligning the machine. The erase head requires no demagnetization. Magnetized heads
w i l l generally produce an increase of 5 to 10 db in noise level, distortion
of the recorded signal, and w i l l gradually erase the high frequencies on
any tape passed over them.
Step 1:
Remove both the head cover and the mu metal shield over the
Step 2:
Step 3:
Place the O N — O F F switch i n the OFF position.
Cover the tips of the demagnetizer w i t h scotch tape or masking tape. This prevents scratching the heads. Plug the demagnetizer into a source of 117-volt a-c power.
The head sequence f r o m left to right when facing the machine,
is erase head, record head, reproduce head. B r i n g the tips of
the demagnetizer into contact w i t h the record head stack. The
Step 5:
Repeat step 4 on the reproduce head. I t is not necessary to
Step 6:
Replace the head shield, but do not replace the head cover i f
alignment w i l l follow.
Demagnetization
Procedure
demagnetize the erase head.
The following steps constitute the complete alignment of the reproduce
channel.
A.
Reproduce Head A z i m u t h Adjustment
B.
Reproduce Level Setting
Reproduce
Channel
Alignment
C. Reproduce Response Check
D.
Reproduce Equalization
E. H u m Balance Adjustment
Step 1:
Thread the alignment tape on the machine. Terminate the
O U T P U T connector w i t h a 600 ohm resistor and connect
the v t v m across this load. Plug a set of high impedance head
phones into the phones jack so that voice announcements on
the tape can be heard. I f not already done, remove the head
assembly cover, but not the m u metal shield beneath it. Place
the M O N I T O R SELECTOR switch i n T A P E position, and
start the machine i n the reproduce mode. The head alignment
tone w i l l be announced first.
Step 2:
Insert a small screwdriver through the access hole nearest the
right hand edge of the head shield, and adjust the azimuth
screw for maximum output observed on the vtvm. // the head
is far out of alignment, several minor peaks occurring on
either side of a maximum may he observed. Make certain that
the m a x i m u m is clearly 15 to 20 db greater than any of these
minor peaks.
Reproduce Head
Azimuth Adjustment
The next tone on the tape is for reproduce level setting. Adjust the
R E P R O D U C E LEVEL (P.B. L E V E L ) potentiometer R137 for a v t v m
reading 10 db below normal operating level, which is approximately
0.4 volts rms.
Reproduce
The next series of tones is for the reproduce response check. Observe
the response indicated on the vtvm, and check i t against specifications.
If reproduce response fails to meet specifications, the trouble may be a
worn or otherwise faulty reproduce head, a partially erased alignment
tape, due to head magnetization, or improper equalization of the reproduce amplifier. Equalization can be checked and adjusted as indicated
below.
Reproduce
Response Check
Level Setting
head assembly.
Procedure
Step 4:
5-2
tips should straddle the gap in the center of the stack. Run
the tips slowly up and down the stack several times, and then
withdraw the demagnetizer very slowly. Slow withdrawal is
required for thorough demagnetization.
The d-c plate supply consists of a f u l l wave rectifier V108, and a capacitor-input L-C filter. A 6.3 volt secondary winding on the power
transformer furnishes a-c power to all heaters. Potentiometer R150
H U M B A L is adjusted for m i n i m u m hum.
5-3
Reproduce equalization (P.B. E Q U A L ) is a bench procedure. The required test setup and the reproduce amplifier response curve are given
in Fig. 5-1. Set the oscillator at 500 cps, and adjust its output for a
vtvm reading 10 db below normal operating level, approximately 0.4
volts rms to establish a reference. Increase the oscillator frequency to
8000 cps and adjust the reproduce equalizer R130 to set reproduce response on the curve at that point. Sweep the oscillator through the
specified frequency range. Response should follow the curve w i t h i n
± f 4 db. Be sure that the oscillator output remains constant over this
range.
Reproduce
Equalization
Equalization procedures are similar for all machines. The only difference
in the procedures is i n the audio oscillator settings for 3 % ips operation.
For 3 % ips reproduce eqtialization, (P.B. E Q U A L ) connect a test set-up
as shown i n Fig. 5.1. Set the oscillator at 250 cycles, and adjust its output for a v t v m reading 10 db below normal operating level. Increase
the oscillator frequency to 4000 cycles and adjust the resistance R130
(P.B. E Q U A L ) to set reproduce response on curve at that point. Response should follow the curve w i t h i n ±1/2 db.
After completing stetps A through D adjusr the H U M B A L A N C E
( H U M B A L ) potentiometer R150 for m i n i m u m hum as seen on a
vtvm connected across the O U T P U T w i t h the M O N I T O R SELECTOR
in T A P E position.
H u m Balance
Adjustment
The steps i n record channel alignment are as follows:
A . Bias Adjustment ( B I A S ) .
B. Record Level Meter Calibration ( R E C . C A E ) .
C. Record Head A z i m u t h
D . Record Equalization & Response Adjustment (REC. E Q U A L ) .
E. Noise Balance Adjustment ( N O I S E B A L ) .
F. Final Bias Adjustment ( B I A S ) .
Record C h a n n e l
Step 1:
Step 2:
Step 3:
Thread a tape on the machine. Terminate the O U T P U T i n
600 ohms and connect a v t v m across this load. Connect an
audio oscillator ser to 500 cycles to the L I N E I N P U T connector and start the machine i n the record mode.
Place the M O N I T O R SELECTOR i n T A P E position and ad-^
just the L I N E REC LEVEL control for a normal operating
level v t v m reading (1.23 volts, or plus 4 d b m ) .
Adjust the BIAS trimmer to peak this output. Make this adjustment carefully because bias w i l l affect the high frequency
response.
3 M ips—For bias adjustment, ( B I A S ) use procedure for lYi
ips machine but with the audio oscillator set at 250 cycles.
After peaking the bias as described i n Step 3 above, and w i t h the
M O N I T O R SELECTOR still i n T A P E position, readjust the L I N E
REC LEVEL control to bring the vtvm reading back to normal operating level. Switch the M O N I T O R SELECTOR to I N P U T position and
5-4
Alignment
Bias A d j u s t m e n t
Record Level
Meter Calibration
5-5
Record level
Meter Calibration
Record Head
Azimuth Adjustment
adjust the REC. C A E potentiometer R114 u n t i l normal operating level
vtvm. The v-u meter is now calibrated, and should read
zero v-u ± 1 / 2 db w i t h the M O N I T O R SELECTOR switch placed on
the I N P U T or T A P E position.
'^^^'^
Step 1:
Step 2:
Record Equalization
Adjustment
(Alternate Procedure)
Step J:
Step 2;
Step 3:
5-6
in
o
CM
CM
10
+
S
Thread a tape on the machine. Terminate the O U T P U T in
600 ohms and connect a vtvm across this load. Connect an
audio oscillator set at 250 cps to the L I N E I N P U T . Place the
M O N I T O R SELECTOR switch on T A P E position. Start the
machine in the record mode, and adjust the L I N E REC LEVEL
control for a vtvm reading 20 db below normal operating level.
\
0
\
m
1
CO
NOTE
W i t h the REC LEVEL controls at m i n i m u m , the bias
pickup as measured on the vtvm should be 30 db below
normal operating level. I f difficulty is experienced because of bias, connect a wave trap in parallel w i t h the
600 ohm terminating resistance. This trap can be a series
LC circuit resonant at approximately 100 kc.
Increase the oscillator setting to 10,000 cycles. Insert a small
screwdriver through the access hole nearest the center of the
head shield and adjust the record head azimuth screw for
maximum output. Be sure to set at the correct peak as described under reproduce head azimuth adjustment step 2.
(REC. E Q U A L ) .
Record eqtialization can be accomplished without disconnecting the electronic assembly from the tape transport. The reproduce channel must be properly aligned and the record head
in good condition. I f these requirements are satisfied, thread
a tape on the machine. Terminate the O U T P U T in 600 ohms
and connect the v t v m across this load. Set an audio oscillator
to 250 cycles and connect it to the L I N E I N P U T connector.
Place the M O N I T O R SELECTOR switch in T A P E position,
and start the machine in the record mode.
Adjust the L I N E REC L E V E L control for a v t v m reading 20
db below normal operating level. Increase the oscillator setting
to 8000 cps and adjust the REC. E Q U A L capacitor C107 for
a v t v m reading 20 db below normal operating level. Frequency response can now be checked by sweeping the oscillator through the range given in the specifications.
The bench procedure for record equalization given i n Step 3
below is independent of the reproduce amplifier and is therefore preferred to the procedure outlined i n Step I above. The
record response curve and test setup are shown i n Fig. 5.2.
Disconnect the electronic assembly from the tape transport.
Disconnect the a-c power plug. Connect a 1000-ohm resistor
between pins 1 and 2 of the Jones Plug P102S, and connect a
vtvm across this load. Strap pins 5 and 6 of P102S together.
Remove the bias and erase oscillator tube V I 0 2 . Reconnect
the a-c power and place the ON-OEF switch i n the O N posi-
10
r-l
rH
o
00
CM
1-4
0
0
0
GO
DV H O i O W t-
+a
00 i-t
ONIIOHD
CO
•OH asvaa
V
1\
r-l
*r
•OH
1
'oaa
co
in
•*
CO
eq
r-l
D
J a,
•4
c
IN
O
o
v.
r"
PI
5
8
o
El
>
PL|
CO
00
O
CO
|H
o
1
r-l
o
pci
->1
§O
o
CM
H
u
H
00
o
r-l
O
CM
O
CM
/
10
eq
-I-
o
10
CM
r-l
-H
+
o
r-l
-I-
m
3^
B
rJ
-I-
5-7
tion. Connect an audio oscillator to the L I N E I N P U T connector J102S, set it to 250 cps and adjust tlie L I N E REC
LEVEL control for a vtvm reading of approximately .4 volts.
Increase the oscillator setting to 8000 cps and adjust the REC.
E Q U A L capacitor C I 0 7 to set the response on curve at this
point as shown in Fig. 5.2. N o w sweep the oscillator slowly
through the specified frequency range and check to see that
response follows the curve throughout. Be sure the oscillator
output remains constant over the range.
3 % ips—For REC. E Q U A L use procedure outlined for record
equalization on 7 Vj ips machine but w i t h the REC. E Q U A L
capacitor C107 adjustment made w i t h the audio oscillator set
at 4000 cycles instead of 8000 cycles.
Record Equalization
Adjustment
(Alternate Procedure)
Noise Balance
Adjustment
Thread a tape on the machine.
Connect a 0.1 m f d capacitor and a sensitive vtvm across the
O U T P U T connector.
Step 3:
Plug a set of head phones into the PHONES jack.
Step 4: Disconnect all inputs.
Step •): Turn the L I N E REC LEVEL and M I C REC LEVEL controls
to zero.
Step 6: Start the machine in the record mode.
Step 7: Adjust the noise balance ( N O I S E B A L . ) potentiometer R147
for a m i n i m u m reading on the vtvm or a m i n i m u m popping
noise in the headphones.
TAPE
TRAVEL
-C203
' 2 20VAC
GIIAA
; 20
450V .
Step 1:
Step 2:
S E E NOTE 10
06A
!2AU7
VI06B
l72 12AU7
^]_CI24
•-T--.001
V
5%
\SU 5 0 0 V
CI25
3 5 0 ppfd.
5 % , 5 00V
ALL
CAPACITORS IN MICROFARADS,
OTHERWISE
4 0 0 VOLTS
UNLESS
NOTED.
A L L RESISTORS
IN OHMS , t i O % , 1/2 WATT U N L E S S OTHERWISE
DC
MEASURED
VOLTAGES
RESPECT
TO
NEUTRAL!,
WITH
20,000 A/V
METER
CHASSIS
PLAY
2,
RECORDS.
SEE D-171116 FOR ELECTRONICS
ASSEMBLY.
Fig. 5-3. Schematic
5-8
WITH
NOTED
jiorp
TAPE
""RAVEL
OUMWV PL UC
V101
6267/EF86
V I 03
I2AU7
VI02
I2AY7
TI03
PLUG IN INPUT
0 iu,)
>
VI05
6267/EF36
VIOL
6F5
-
-
t
RI24 + CI14A
lOK
- : 20
• iW
- 450V,.
_
vio6
I2AU7
_
_
0.9
TRANSFORMER
^^^AAv
278 ( 2 3 7 )
7)83 (76)
V106A
1/2 I2AU7
"
RED
_ ^ J g > J i 8 (80)
NM
VI08
5Y5
e.
FOR HIGH IMPEDENCT INPUT,
INSTALL DU'-IMY PLUG J107P
7.
FOR 150 OHM TO ?.E0 CHM
INPUT IMPEDENCE,INSTALL
INPUT TRANSFORMER TI03
IN J I 0 6 S
e. FOR 30 OHM TO 50 OHM
INPUT IMPEDENCE, INSTALL
TRANSFORMER T l 0 3 IN
J106S AND REMOVE JUMPER
FROM 6 TO 7 AND CONNECT
TO A ON
II 06S .
s OUTPUT
1 \
J20IS
PLAYBACK
HEAD
CII6
:.039
5%
P8
EOUALi
Si>RI30
T
3>A
10.
|3,0K
Rise
aEK
CI24
.001
5%
500V
3
CI25
3 5 0 ppftl
5%.5
00V
i' 7 2 - J "151
T ' V T ^ 560
.;, W8v\2.^
PHONES
ORCUir
OUTPUT
1
ADD C-130 FOR 17418-07
vloe
5Y3
1).,
T102
TAPE
FOCt" FYiODCl. taOa OHit-V
1.
"AL
SI02
INPUT
(0.83)
2.
5.
TIQA B L U E
A L L R E A D I N G S M E A S U R E D TO GROUND W I T H 2 0 , 0 0 0 OHM
PER V O L T M E T E R .
INPUT VOLTAGE I I 7 V A C .
UPPER R E A D I N G S V O L T A G E , F I R S T R E A D I N G REPRODUCE
M O D E , SECOND R E A D I N G RECORD M O D E ,
NM MEANS NOT M E A S U R E D .
NC MEANS NOT C O N N E C T E D .
41045
+309V|—VV\rLI02
5.5 hy
+
~^Cll4B
+
—^riirt,-
+
+
,
0.1030 —'—010'*'
ALL CAPACITORS IN MICROFARADS, 4 0 0 VOLTS
OTHERWISE NOTED.
UNLESS
A L L RESISTORS IN OHMS , ± 1 0 % , 1/2 WATT U N L E S S OTHERWISE NOTED.
DC VOLTAGES
RESPECT
NEUTRAL!,
A
(set
MOTES']
MEASURED
WITH
2 0 , 0 0 0 A / V METER
TO CHASSIS.
PLAY 2 ,
RECORDS.
SEE 0 - 1 7 4 1 6 FOR ELECTRONICS ASSEMBLY.
A t
Fig.
5-3.
Schematic
WITH
VI. Parts List
The following parts list provides ail information
necessary for ordering replacement parts. Always
use Ampex Catalog numbers when ordering parts. To
expedite processing, always include the following information in placing parts orders:
A.
B.
C.
D.
Model Number
Serial Number
Ampex Catalog Number of Part
Part Description
EXAMPLE:
Spring, Clutch "U". No. 6246, for Model 601.
Serial No. 6D0042.
Reference
Symbol
83
85
84
78
78
79
80
75
10
11
1
13
14
2
Ampex
Catalog
Number
Description
Tape Guide Assembly
Bar, Tape Guide
Cap, Tape Guide
Ball Bearing
Machine Screw, Phillips Hd., 6-32 x 3/4
Shim Washer, . 149 ID x 5/16 OD x . 025 thk, brass
Shim Washer, . 149 ID x 5/16 OD x . 031 thk, brass
6201
6202-1
421-029
MS-24-6-12N *
PW-4B-25-149X
PW-4B-31-4 *
Turntable
Machine Screw, Flat Head, 4-40 x 1/4
Capstan Idler Assembly, with Oilite bearing
Cap, Capstan Idler
Cambric Washer, . 24 ID x 7/16 OD x . 010 thk
Hairpin Retainer for 1/4" shaft
6205
MS-34-4-4N
6211-1
6203
9482
431-006i
Link, Turntable Pivot
Cotter Pin, 1/16 x 1/2"
Clevis Pin, 1/8 x 11/32"
6221
401-005
400-004
Sub-Plate Assembly
Spring, Rewind Idler
Spring, Release Lever
Sub-Plate Casting
Slide Lever, Brake Actuator
Release Lever, Play Mode Brake
Brake Shock Relief Assembly
6227-1
6136
6215
6275
6277
6278
6279-1
6-1
Reference
Symbol
7
8
12
9
53
51
52
54
63
62
61
65
68
66
71
6-2
Description
Rewind Idler Assembly
Idler Wheel with Oilite bearing
Guide Assembly
Cambric Washer. .24 ID x 7/16 CD x .010 thk
Plastic Retaining Ring
Actuator Spring, 11/64 dia x 1" long
Spring Washer, Clevis Pin, 3/8 x 13/16
Switch Deck Assembly
Guard, Switch Top
Lamicoid Washer, Side Lever, 1/8 ID x 5/8 ODxl/32 thk
Lockwasher, #4 Int. tooth
Screw, #4-40 x 1/2"
Nut, #4-40 Hex
Cotter Pin, 1/16" x 1/2" long
Clevis Pin, 1/8 x 15-32" long
Clevis Pin, 1/8 x 21/32" long
Clevis Pin, 1/8 x 27/32" long
Plain Washer, #10
Hairpin Retainer for 3/16" shaft
Resistor Barrier
Switch Guard, side
Capstan Idler Arm Assembly
Anchor
Arm Sub-Assembly
,
Roller
Spring, 21/64 x 1-27/64" long
Clevis Pin, 1/8 X 15/32" long
Motor Assembly
Felt Washer, 15/64 ID x 3/4 CD x 1/16" thk
Motor
Mounting Plate
,
. ,. , ,
Pulley, 60 cps, 7-1/2 ips
.
.
50 cps, 7-1/2 ips
60 cps, 3-3/4 ips
;
50 cps, 3-3/4 ips
Screw, 8-32 x 3/8" long
Sem Fastener, 8-32 x 3/8" long
Soldering Lug
Thrust Disc, Nylon, . 312 dia x 1/16" thk
Drive Belt, Nylon, 60 cps, 7-1/2 ips
50 cps, 7-1/2 ips
60 cps, 3-3/4 ips
50 cps, 3-3/4 ips
Spring, Motor Thrust, 5/16 x 1-7/8" long
Plunger, Motor Thrust
Spacer, Motor Mounting, 1/4 CD x . 531 long
Ampex
Catalog
Number
6284-1
6285
6288
9482-1
430-095
9368
6314
9064-1-C
9728
6318
LW-21-4C
MS-12-4-8C
NU-1-4C
401 -00.5
400-007
X C t./<J
400-010
400-011
PW-l-lOC
431-002
9726
9727
6235-1
6224
6236-1
6237
6910
400-007
6219
6239
6240
6241-0
6241-1
6241-2
6241-3
MS-12-8-6C
SF-2X-8-6C
SL-1
6934
2871-3
2871-6
2871-7
2871-14
7531
7532
7582
Reference
Symbol
60
*
*
*
*
*
*
*
*
*
*
20
26
24
29
17
19
18
15
16
28
27
23
25
21
22
*
*
*
*
*
+
*
36
38
32
30
31
35
33
37
Description
Rubber Shockmount
Ball, 1/4" dia.
Motor Mount Washer, C. R. S. 13/64 ID x 5/8 CD
Motor Mount Screw, Binder Hd., 10-24 x 7/8" long
Socket Hd. Set Screw, 8-32 x 1/8 long, cup point
Ampex
Catalog
Number
7922
420-006
2431
MS-12-10-14C
SS-2-8-2Y
Takeup Arm Assembly
Spring, Conical, 1" dia. x 31/32" long
Control Spring, 17/32 x 13/16" long
Thrust Washer, .015 spring steel, 1/4 ID x 3/8 CD
Pivot Arm
Hub, with Shaft
Spring, Clutch "U"
Clutch, Play Takeup
Disc Assembly, with small felt
Disc Assembly, with large felt
Clutch Assembly, fast forward, with Oilite bearing
Link, Turntable Control
Washer, Spring Retaining, Cup
Collar, Drum
Brake Assembly, Holdback
Use Replacement Holdback Brake Assembly Kit
(Each ket contains two Brake Assemblies)
Lamicoid Washer, 1/4 ID x 1/32" thk
Oilite Bearing
Ball Bearing
Cotter Pin, 1/16 x 1/2" long
#4 Lockwasher, int. teeth
Binding Hd. Machine Screw, 4-40 x 5/16" long
Hex Nut, 4-40
Socket Hd. Set Screw, 6-32 x 1/8" long
6242-1
6137
6218
6223-1
6243
6244
6246
6247
6248-1
6248-2
6251
6253
6254
6293
Spring, Turntable Height 11/32 x 9/32" long
6217
Rewind Arm Assembly
Thrust Washer, .015 spring steel, 1/4 ID X 3/8 OD
Pivot Arm
Hub, with shaft
Spring, Clutch "U"
Disc Assembly,^ with large felt
Clutch Assembly, rewind, with Oilite bearing
Collar, "Drum"
Collar, Spacer
Holdback Brake Assembly
Use Replacement Holdback Brake Assembly Kit
(Each kit contains two #6320-1 Brake Assemblies)
Lamicoid Washer, 1/4 ID x 1/32" thk
6255-1
6223-1
6243
6244
6246
6248-2
6251
6293
6316
7974
186-1
422-004
421-019
401-005
LW-21-4C
MS-12-4-5C
NU-1-4C
SS-2-6-2Y
7974
186-1
* Items marked with the asterisk (*) are included in Kit #7802.
6-3
Ampex
Reference
Symbol
Description
Ampex
Catalog
Reference
Number
Symbol
Catalog
Number
Description
_y
34
Ball
Bearing
421-019
#4 L o c k w a s h e r ,
Int. teeth
LW-2I-4C
Mi:>-i4-4—oO
A^A
•NTiif
XXCA
64
T u r n t a b l e Height S p r i n g ,
Af^
shaft & b a l l
6262
if
82
Cap,
6273
65
T h r u s t D i s t , Nylon,
11/32 x 9 / 3 2 " long
6217
15/64 I D x 3/4 O D x 1/16" thk
Dust Shield
Cambric Washer,
. 2 4 I D x 7/16 O D x . 0 1 0 thk
S p e c i a l Set S c r e w ,
70
/\i
V^OIILI O i
,rt.etuaior,
to
/VSoeulDiy
III
Capstan Thrust, 3/8-27 x 1-1/8"
xxuxx
Jrixi, o / o ^ j
6257
Rewind/Fast
A
Actuator,
49
vj W XLX^'Xl X V X C ^ X ^ l X c X I l l o I I X
50
"Rnll
P i n
Rewind/Fast
'\/'\9
X I X , O/O^
B a l ilV v X X^X / Xl^ fi"
dia
OtJ/
tlO
l Xf" TX^c oJ n
J^ J4 fCi X
l Xcoi X n
Un
i XiXTlilrgr
41
T91 O T r ' T o t ' t m Y ^
JTLcLy
XftAOUp
Spring
Assembly
Forward
Y
"^/R"
Inner
A
O/O
XOIlg
A v*Ty^
/ A X 111
Y
A 1
X u //1
I DA "
39
XXX 111 i X D O C l H i J l V
with Oilite bearing
xidixpin xveLdinei
X c X A c U p ,DOXL,
X yjw x r i d x c i
l-iCidl
GoTYi
1 lAW
fxTart-W-
l o i x / f
snan.
-fj-xv
X A U O U O I
S e m F a s t e n e r , 4 - 4 0 x 1/4", i n t . t e e t h
SG-2I-4-4C
C
MS-26B-4-28N
R e e l Hold Down Knob
6319
Detent S p r i n g ,
6911
220V
iViounLing o c r e w ,
Contant m i n
x j i n u e r i i u , , o—o^ x
17512
Rewind Control
KN-7
Tab.
17286-1
Belt Tension
L a m i c o i d W a s h e r , 5/16 I D x 1/32 t h k
186-0
1/4 I D x 1/32 t h k
186-1
1/4 I D x 1/64 thk
186-2
fi994
Lamicoid Washer,
5/16 I D x 1/64 t h k
186-3
or - 4 A - b - 4 0
L a m i c o i d W a s h e r , 1/4 I D x 1/16 t h k
186-4
r'T?
PORTABLE
9417-4
*
*
*
A 14
yi o
CASE
ASSEMBLY,
Saddle T a n
9065-1
R u b b e r S h o c k m o u n t Nut, T o p P l a t e
CO-327
Plastic Foot
TTD
J X i r '1- l - o L /
if
Mb - I Z - o - l U C
if
X
*
CS-5
Cable
B a r Knob, w i t h s e t s c r e w
Lamicoid Washer,
or'
o/o
420-004
L e a f Spring,
Lamicoid Washer,
(4ob
Lrxx-4U
bearing
Electrolytic, 2.5mfd,
Steel B a l l , 5/16" d i a .
Power
*
7798-2
Plastic Reel
D4oy—1
T
P
x rnOab fL
Rewind A r m
Jj—Ot)
6937-1
3/8 i n . l o n g
7666
5/8 i n . l o n g
BU-3
Mounting H a r d w a r e f o r P l a s t i c F o o t :
KP-1-6
6 - 3 2 K e p Nut
x . tn
; Xe, s v P
U lllu
t dgl - ' R
L ,e t a
1 1i1 n
1 1e
1 .r
S-1 pL rI Ui On gX,J x J tJ' t o
16340-1
6 - 3 2 X 1/2 B i n d i n g H e a d M a c h i n e
Screw
MS-12-6-8 or
Head Cable Harness
9068-1
6 - 3 2 X 5/8 B i n d i n g H e a d M a c h i n e
Screw
MS-12-6-10 or
6 - 3 2 X 3/4 B i n d i n g H e a d M a c h i n e
Screw
MS-12-6-12 or
Screw
MS-12-6-14
Assembly
*
*
*
6283
76
J202D
Jones Plug
PL-8P
6 - 3 2 X 7/8 B i n d i n g H e a d M a c h i n e
R202
R e s i s t o r , 20 K o h m
043-080
No. 6 P l a i n S t e e l W a s h e r
S o l d e r T^ug
SL-3
Hinge L e a f ,
no p i n
Hinge L e a f , w i t h f i x e d p i n
6-4
1-3/4"
if
0£^0t
Q
9j
o —9
O/
Snokpt
if
4oZ-UiU
XVlIlg
Top Plate Casting, with g r i l l & Oilite
v-'dpaciLoi
4-40 x
88
7"
*
\ J
AjioiniiieL
TCori
X A O p "MnT
XNUL,
6213
Assembly
C o r k W a s h e r , 1/8 I D x 2 1 / 3 2 O D x 3 / 3 2 " t h k
if
77/89
lob-i
o o x x i O CJ" R
X
ew
D LnXl IrUi
Tube
t\Jo—\j\jA
431-UUb
G/-»T»4xiir
Motor Capacitor,
6208-1
SF-2I-6-4C
x / t xxj A x / o u " u i x
X NTCnUnInX
X
C203
6207-1
Head
S e m F a s t e n e r , 6 - 3 2 x 1/4", i n t . teeth
Q4R9
/ A o o d x i u i v
TX na pntp; vriniHp
jruxtxt;
Tape Guide,
6206-10
Assembly
ft9R1
DdOX
6268
kJJL/1 l l l g
i:>idbb
Head
Phillips Oval Hd. Machine Screw,
«970
Wdoiiei,
91
D4b/-1
Y
"D y-, 4- r i 1 TX CA >-•
xjcixxxicuiu.
Cover,
6206-20
6258
C91
Cambric Wnahcr
24- TD x 7 / I 6 O n x (11 fl thk
W d i i i f j l 1 L » VV d o l l C l , • 4 j 7 t l l _ / A . 1 / X vX \JXJ A • V/ X U LXX A
T.QminniH W p o T m r * 1 /A T P 1 / R 9 t T f > i b TTQiT»nin
86
half t r a c k
full t r a c k
Shield, Head
6138
Pulley Assembly,
Head A s s e m b l y ,
6259-1
bzbo-1
1l Onnrr
Ilg
A ctcj£i"»v»l^lTr
/Abtjoinuiy
40
MS-32-27-1125
NU-16-616C
*
*
*
*
0 U0U4^
*4 t9 40 U —
T
oT
V I /A
oT
X rUiXl O
X * /AA TX* T111
A oOEtasO
X vl il VUiXl Tyr
1X X1 / /(\A
D T : Hi
U l cQt ,
C lpnXnXi lnXc gr ,
O
406-002
long
Forward Control
48
90
6261
o/o
9482
6256-1
xriay
owiucn iviecnanifaui
An
11
*
6219
6934
. 3 1 2 d i a . x 1/16" thk
Hex J a m Nut, 3/8-27
Xriay
9353-1
F e l t W a s h e r , 1 3 / 1 6 I D x 1-1/8 O D x 3 / 3 2 " thk
*
long
flywheel,
43
SS-2-8-3Y
i/o
with
if
8 - 3 2 x 3 / 1 6 " long
Socket Hd. Set S c r e w ,
x
Capstan Assembly,
D u s t S e a l , felt,
•if
o—o/s
42
81
JNU - 1 - 4 C
Co o c o v
bb-2-D-2Y
oeu o c i e w ,
nu.
1
XTT T
r\
t~'t\J
INlXt,
oueAtJL
*
PW-1-6
Hl-6
HI-6-1
6-5
Reference
Symbol
ClOl
C102
C103
C104
C105, c m ,
Description
Ampex
Catalog
Number
C107,C113
C108
C l i o , C122
C112
C114
C115
C116
C118
C123
C124, C127
C125, C126
M l 01
V - U Meter
M E T E R , glass
R E T A I N I N G RING: self locking
6351
PS-4
430-039
RlOl
R102,R122,
R139
R103
RESISTOR, composition: 2.2 megohm 1/2 watt
RESISTOR, composition: 2, 200 ohm 1/2 watt A - B
L a t c h , Fastener
Catch, Fastener
No. 8 Oval P h i l l i p s Sheet M e t a l Screw, type Z
8-32 X 1/2 Oval P h i l l i p s Machine Screw
T i n n e r m a n Nut, Electronics
Handle
Handle-mounting, Cap, b r a s s
Mounting r a i l , r i g h t hand
Mounting r a i l , left hand
LO-16
LO-17
MS-21-8-10N
MS-26-8-8N
SN-3U-8Z-1
HA-7
CA-21
7528-1
7528-2
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR:
CAPACITOR,
e l e c t r o l y t i c : 3x40 uf, 252; M a l l o r y WP 520.
tubular: . 1 ufd 400 v; C-D No. ST4P1
e l e c t r o l y t i c : 4x10 ufd 450v; M a l l o r y FP-434
.047 ufd 400 v ; C-D ST4S47
tubular: .0047 ufd 400 v ± 5%; C-D ST4D47
CO-328
CO-294
CO-68
CO-347
CO-334
R104,R105,
R135
R106
CAPACITOR,
CAPACITOR,
CAPACITOR;
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR,
CAPACITOR,
tubular: . 1 ufd 400v; C-D ST4P1
t r i m m e r : 100 uuf; E l Menco 302 type 30
. 1 ufd 200v t 5%; C-D ST2P1
c e r a m i c disc: . 0 1 ufd; Centralab DDI03
tubular: .5 ufd 400v; Sangamo 300 405
e l e c t r o l y t i c : 3x20 ufd 450v; M a l l o r y 376.5
e l e c t r o l y t i c : 1000 ufd 6v; Spraque TVA-1104
paper: . 039 ufd 400v 5%
paper: . 022 ufd 400v; C-D ST4S22
e l e c t r o l y t i c : 4 ufd 150v
m i c a : .001 ufd 500v t 5%; Sangamo KR-1210
m i c a : 350 uuf 500v ± 5%; Sangamo KR
CO-294
CO-92
CO-335
CO-338
CO-330
CO-236
CO-329
CO-523
CO-380
CO-53
CO-6
CO-140
R108, R123,
R134
R107
C121
C106
Description
Ampex
Catalog
Number
Reference
Symbol
FlOl
FUSE: 1 ampere 250v; Littlefuse 312001
FUSE HOLDER, w i t h Hardware
070-003
FE-5
JIOIS
PL-320S
J102S
J103S
J104S
J105P
J107P
CONNECTOR: microphone input, 3 contact shielded;
Cannon X L - 3 - 1 3 N
JACK: M i n i a t u r e phone, 2-conductor; Switchcraft 41
JACK: phone; Switchcraft 11
JACK: output phone; 3 conductor ,
CONNECTOR, m i n i a t u r e : power 2 contact; GE 2711
PLUG, octal: dummy plug assembly
CONNECTOR, tape t r a n s p o r t connector: Jones S-308-cct
CONNECTOR: reproduce head cable; Jones P - 3 0 2 - c c t - L
JA-28
JA-21
JA 33
PL-319P
17420-1
PL-69S
PL-338P
LlOl
L102
CHOKE, r - f : 20 mhy; M i l l e r 691
CHOKE, 5.5 h y : M e r i t C-2975
CH-8
CH-62
R109, R l l O
Rill
R112, R144
R113,R117,
R140
R114,R125,
R137
R115,R131,
R138, R141
R116
R118
R119
R120,R127
R121
R124
R128,
R129
R130
R132
R133
R136
R142
R143
R145,R146,
R148, R149
R147
6-6
EB-2221
RESISTOR, carbon f i l m : 82, 000 ohm 1/2 watt 350v;
Sternog type A - 1
RESISTOR, carbon f i l m : 100, 000 ohm 1 watt 500v;
Stemog type A-2
P O T E N T I O M E T E R , audio taper: 100, 000 ohm;
A - B JA1041 SD3056
RESISTOR, carbon f i l m : 47, 000 ohm, 1/2 watt 350v;
Stemog type A - 1
RESISTOR, composition: 22, 000 ohm, 1/2 watt;
A - B EB-2231
RESISTOR, composition: 270,000 ohm, 1/2 watt; A - B
EB-2741
RESISTOR, composition: 1, 500 ohm 1/2 watt ± 5%
RESISTOR, composition: 47, 000 ohm 1/2 watt;
A-B
EB-4731
RESISTOR; 100, 000 ohm 1/2 watt; A - B EB-1041
P O T E N T I O M E T E R , audio taper: 250,000 ohm;
Centralab BA-011-1224
RESISTOR, composition: 1 megohm 1/2 watt; A - B
041-086
041-052
042-014
042-011
044-015
042-013
041-064
041-077
041-008
041-068
041-072
044-042
EB-1051
RESISTOR, composition: 33, 000 ohm 1/2 watt i 5%
RESISTOR, composition: 560 ohm 1/2 watt; A - B EB-3311
RESISTOR, composition: 47, 000 ohm 2 watt; A - B EB-4731
RESISTOR, composition: 470,000 ohm 1/2 watt;
A - B EB-4741
RESISTOR, composition: 470 ohm 1/2 watt; A - B EB-4711
RESISTOR, composition: 10, 000 ohm 1 watt; A - B EB-1031
RESISTOR, composition: 1,800 ohm 1/2 watt
RESISTOR, carbon f i l m : 220, 000 ohm 1 watt 500v;
Stemog type A-2
P O T E N T I O M E T E R , audio taper: 10,000 ohm; IRC type Q
RESISTOR, composition: 1. 2 K ± 10% , 1/2 watt
RESISTOR: 15,000 ohm 1/2 watt
RESISTOR: 330, 000 ohm 1/2 watt
RESISTOR, composition: 820 ohm 1/2 watt; A - B EB-8211
RESISTOR: 10, 000 ohm 2 watt
RESISTOR, composition: 4, 700 ohm 1/2 watt;
A - B EB-4721
P O T E N T I O M E T E R , l i n e a r taper: 10,000 ohm; IRC type Q
041-031
041-017
041-045
041-220
041-080
041-044
041-158
041-051
042-012
044-039
041-049
041-062
041-078
041-047
041-213
041-056
044-050
6-7
.
Reference
Symbol
Description
Ampex
Catalog
Number
POTENTIOMETER, linear taper: 100 obm; M a l l o r y type C-P
RESISTOR: Composition 560 ohm 1/2 watt 10%
RESISTOR, composition: 82 K , ±10%, 1/2 watt
SWITCH, SPST toggle: 3 amp 250v; C-H 8280 K15
SWITCH, SPDT wafer: n o n - s h o r t i n g : Oak 59016-23
044-095
041-045
041-246
SW-74
SW-66
TlOl
T102
T104
TRANSFORMER: power
TRANSFORMER: bias and erase
TRANSFORMER: output
6298
6352
17419-1
VI01,VI05
V102
V103,V106,
V107
VACUUM T U B E : 6267/EF86
VACUUM T U B E : 12AY7
VACUUM T U B E : 12AU7
012-028
012-043
012-023
VACUUM T U B E : 6F5
VACUUM T U B E : 5Y3GT
T U B E SHIELD
012-042
012-013
SD-13
SHIELD, choke
Special Adjusting Screw w i t h Retainer Sleeve
T i n n e r m a n Cable Clamp for 6-32 Screw
Plastic Cable Clamp
Knob, 1-1/2 i n . d i a . s k i r t
No. 12 Lockwasher, I n t e r n a l Teeth
3/8 Lockwasher, Internal Teeth
3/8 Lockwasher, Internal Teeth, Fine
1/2 Lockwasher, Internal Teeth, Fine
6-32 X 1 i n . Long Bind Head Brass Machine Screw
No. 12 Plain Brass Washer
F i b r e Washer, 3/8 ID x 5/8 OD x 1/32 i n . thick
Pan Head Sem Fastener, 6-32 x 3/8 i n . long
" J " type T i n n e r m a n Nut for 6-32 screw
F l a t Latch Type T i n n e r m a n Nut f o r 6Z screw
3-lug Tie Point
2-lug Terminal Strip
2-lug T e r m i n a l S t r i p , Right Lug Grounded
Washer, Condenser insulating
Bottom Plate
9188-1
BO-4-4
CL-72
KN-14
LW-2I-12C
LW-2I-616C
LW-6I-616C
LW-6I-816C
MS-12B-6-16C
PW-1B-12C
PW-3-5
SF-2I-6-6C
SN-3J-632-1
SN-3L-6Z-1
TS-5-4
TS-5-3
TS-6-1
6094-1
6399-1
ACCESSORIES
Head
Demagnetizer
Amplifier-Speaker Model 620:
In portable Samsonite Case, saddle tan
In " B r u n e t t e " F u r n i t u r e Cabinet
In " B l o n d e " F u r n i t u r e Cabinet
6-8
704
9419-2
7950-1
7950-2
Reference
Symbol
Ampex
Catalog
Number
Description
601-620 Interconneeting Cable Assembly, 8 f t .
601-620 Interconnecting Cable Assembly, 20 f t .
Adaptor for Rack Mounting
9411-1
9411-2
9684-1
P l u g - i n Low Impedance Microphone
Input T r a n s f o r m e r
17331-1
Tape Speed Conversion K i t s
F o r f i e l d applieation, includes pulley, belt, standard alignment tape
f o r new speed, and complete installation and alignment instructions
f o r converting f r o m 7-1/2 in/sec. to 3-3/4 o r vice v e r s a .
FOR 60 CYCLE MACHINES
Change f r o m 7-1/2 ips to 3-3/4 ips,
7556-0
Change f r o m 3-3/4 ips to 7-1/2 ips,
7556-1
FOR 50 CYCLE MACHINES
Change f r o m 7-1/2 ips to 3-3/4 ips,
7556-2
Change f r o m 3-3/4 ips to 7-1/2 ips,
7556-3
Power Frequency Conversion K i t s :
F o r converting 7-1/2 ips machine f r o m operation
c u r r e n t to operation on 50 cps c u r r e n t
F o r converting 7-1/2 ips machine f r o m operation
c u r r e n t to operation on 60 cps c u r r e n t
F o r converting 3-3/4 ips machine f r o m operation
c u r r e n t to operation on 50 cps c u r r e n t
F o r converting 3-3/4 ips machine f r o m operation
c u r r e n t to operation on 60 cps c u r r e n t
Each k i t contains the appropriate pulley, belt and
mounting i n s t i u c t i o n s .
on 60 cps
9738
on 50 cps
9739
on 60 cps
9740
on 50 cps
9741
Can of O i l , C a l o i l T u r b i n e # 1 1 , 4 oz.
1/2 oz.
Alignment Tape, 7-1/2 ips
3-3/4 ips
FP-5
TO-9
5563
6000
Spare Parts K i t for 7-1/2 ips 60 cps Machines
Contains following p a r t s :
9742-1
D r i v e Belt
Capstan Idler
Spring
F e l t Clutch L i n i n g (Rewind)
F e l t Clutch L i n i n g (Takeup)
Rewmd I d l e r
Reel Hold Down Knob
2871-3
6211
6246
6250
6250-1
6284
6319
Reference
Symbol
Description
4
Rubber Shockmount
1
Filter Capacitor - 1000 Mfd., 6 Volts
1
Fuse - 1 amp.
1
Takeup Belt
1
Potentiometer - lOOK
1
5Y3GT Vacuum Tube
1
12AU7 Vacuum Tube
1
5879 Vacuum Tube
1
6F5 Vacuum Tube
1
12AY7 Vacuum Tube
Spare Parts Kit for 7-1/2 ips 50 cps Machine
Contents same as 9742-1 except for belt
Spare Parts Kit for 3-3/4 ips 60 cps Machine
Contents same as 9742-1 except for belt
Spare Parts Kit for 3-3/4 50 cps Machine
Contents same as 9742-1 except for belt
.-10
Ampex
Catalog
Number
,
6937
CO-329
070-003
432-010
044-015
012-013
012-023
012-028
012-042
012-043
9742-2
2871-6
9742-3
2871-7
9742-4
2871-14
Maintenance Kit Contains following parts:
6392
Quantity
2
Control Spring
2
Spring Clutch "U"
2
Nylon Thrust Disc
4
Rubber Shock Mount
6
Cotter Pin (l/16"x 1/2" N.P.)
2
Clevis Pin (1/8 dia. x 15/32)
2
Clevis Pin (1/8 dia. x 19/32)
2
Clevis Pin (1/8 dia. x 25/32)
1
Oil Can (1/2 oz.)
4
Self Threading Screw (Electronics Chassis)
4
Phillips Head Screw (Top Plate Assembly)
2
Hairpin Retainer (For 3/16" Shaft)
2
Hairpin Retainer (For 1/4" Shaft)
2
Hairpin Retainer (For 7/32" Shaft)
2
Self-Locking Nut ("J" Tinnerman for 6/32" Screw)
1
Phillips Driver (2-3/4" Overall)
1
Flat-Bladed Screwdriver (3-1/2" Overall)
1
Allen Wrench (1/16" across flat x 1-3/4" Arm)
1
Allen Wrench (5/64" across flat x 1-3/8" Arm)
Minor Hardware Kit
Contains 250 small parts normally used in servicing.
6218
6246
6934
6937
401-006
400-007
400-010
400-016
TO-9
MS-21-8-8N
MS-26-8-8N
431-002
431-006
431-004
SN-3J-623-1
TO-7
TO-8
TO-5
TO-6
7802
Hold-back Brakes Replacement Kit
Contains two Holdback Brake Assemblies #6320-1.
7974-1
TM
lOOl
Operation
Maintenance
AMI PIfix
M O D E L 601
Manual
1
AMPEX
CORPORATION
934 CHARTER STREET
REDWOOD CITY - CALIFORNIA
i