Ampex 351 - Page 21

FLUTTER AND WOW
DISTORTION
To
Cable Chassis Chassis
A-c
(1)
(1)
(1)
Captive at Tape Transport
(1)
Captive at Tape Transport
05-0157-01
(1)
05-0159-01
(1)
05-0160-02
(1)
05-0159-02
NOTE: Cables marked with a red band, interconnect in upper electronics for
the Model 351-2 only.
3-6
Receptacle
A-c source
Overall distortion can be measured by con 
necting any standard distortion measurement
Complete instructions for making the above
checks are given in the “ Alignment and Per 
formance Checks ” paragraphs of SECTION 8.
Bias
Interconnecting
Power
Interconnecting
Power
Interconnecting
Reproduce
Head
Power
Extension
Record
Head
Erase
Head
PORTABLE
SINGLE TRACK
J7 TAPE
TRANSPORT
J3 PLAYBACK
HEAD
J7 TAPE
TRANSPORT
J2 RECORD
HEAD
J 10 ERASE
HEAD
Electronic
Assembly
1 and 2
Electronic
Assembly
1 and 2
Electronic
Assembly
Electronic
Assembly
Electronic
Assembly
Electronic
Assembly
Electronic
Assembly
Electronic
Assembly
J9 BIAS
COUPLING
To
Slave Electronic
Assembly
89-0144
Issue A
Catalog
Number
05-0156-01
Qty
(1)
From
Receptacle
J8 POWER
Flutter and wow are produced by periodic
irregularities in tape speed and appear as fre 
quency deviations in recording or reproduction.
They can be measured by means of a calibrated
flutter test tape (see “ Accessories ” section) and
a standard flutter bridge. Readings will be near
or below 0.11% rms at 15 ips, 0.14% rms at
7 Fa ips, and 0.18% at 3% ips. The Ampex pri 
mary standard of measurements is based on
the use of a flutter meter calibrated to indicate
the deviation from mean carrier frequency of
any rate between 0.5 and 250 cps expressed in
percent rms.
apparatus across the output. The readings from
a wave analyzer or selective frequency distor 
tion meter will be more accurate than those
from a null type instrument at lower distortion
levels. Distortion readings are somewhat de 
pendent on tape. A reading of 1% is normal
at operating level while a reading of 3% is
normal at 6 db above operating level. Second
harmonic distortion is negligible; measured
distortion is predominately third order.
INTERCONNECTING
SINGLE TRACK
produce frequency response within
specifications when recording on an
average tape. In the last few years the
high frequency output from tape
has improved tremendously. In order
to keep pace with these improvements,
in the summer of 1959 Ampex selected
a. new “ average ” tape to adjust bias
and record equalization. Machines ad 
justed to the new average tape may
be identified by the catalog number
of the electronics, No. 02-30960 repre 
senting the revised machine. The
02-30960 electronics also are adjusted
for a 3% inches per second (ips) play 
back response curve incorporating a
120 microsecond turnover.
End of Captive Tape Transport
power interconnecting cable.
End of Captive Tape Transport
power interconnecting cable.
End of Captive Tape Transport
power interconnecting cable.
From
J9 BIAS
COUPLING
DUAL TRACK EQUIPMENT
(Unmounted)
J7 TAPE
TRANSPORT
Master
Electronic
Assembly
DUAL TRACK EQUIPMENT
(Portable)
J7 TAPE
TRANSPORT
CABLE TO Captive at
ELECTRONICS Tape Transport
Captive at Tape Transport