Ampex 351 - Page 99

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Head Demagnetizer
TEST TAPES
Issue A
A-6
The A mpex test tape mentioned in the
“ Checkout and Adjustment ” section is specifi 
cally designed for use with machines operating
at 7 ’ / 2 inches per second using NAB equaliza 
tion. Under certain circumstances, particularly
for “ Master Recording ” , it may be desirable to
calibrate the machine with the test tape de 
signed for the specific speed and equalization
Equalization
15 ips NAB
7 j /2 ips NAB
3% ips 120 Msec
3% ips 200 Msec
Catalog No.
01-31311-01
01-31321-01
01-31331-01
01-31334-01
HEAD DEMAGNETIZER AND HEAD CLEANER
The A mpex head demagnetizer, Model
No. 820, quickly demagnetizes the record, re 
produce and erase heads to achieve reduced
noise and distortion. The demagnetizer neutral 
izes the residual magnetizing induced in the
heads by transients from speech, music and
noise thus preventing partial high frequency
erasure of the tape. The demagnetizer consists
of an a-c magnet with pole pieces shaped to
fit the contour of the heads. Operation of the
demagnetizer is described in the HEAD AS 
SEMBLY section.
The A mpex head cleaner. Model No.
823, is specially formulated for use with
A mpex heads. Do not use any other solvent on
the head assembly as some will damage the
material which binds the head laminations to 
gether. The head cleaner should not be used
on plastic parts such as the head cover. Clean 
ing of the heads is described in the HEAD AS 
SEMBLY section.
The 15 ips test tapes contain the following
information in the sequence indicated.
A 700 cps tone at operating level for re 
duce gain calibration and reference.
A 15,000 cps tone at operating level for
reproduce head alignment.
A series of tones (12kc, lOkc, 7.5kc,
5kc, Ike, 500c, 250c, 100c, 50c, and 30c)
at operating level for reproduce fre 
quency response measurements.
The 7 1 /a ips test tapes contain the following
information in the sequence indicated.
A 700 cps tone at 10 db below operating
level for reference.
A 15,000 cps tone at 10 db below operat 
ing level for reproduce head alignment.
A series of tones (12kc, lOkc 7.5kc, 5kc,
2.5kc, Ike, 250c, 100c, and 50c) at 10
db below operating level for reproduce
frequency response measurements.
A 700 cps tone at operating level for re 
produce gain calibration.
The 3% ips test tapes contain the following
information in the sequence indicated.
1. A 500 cps tone at 10 db below operating
level for reference.
2. A 7,500 cps tone at 10 db below operat 
ing level for reproduce head alignment.
3. A series of tones (5kc, 2.5kc, Ike, 500c,
250c, 100c and 50c) at 10 db below op 
erating level for reproduce frequency re 
sponse measurements.
4. A 500 cps tone at operating level for re 
produce gain calibration.
concerned. The following table lists the various
’ A-inch test tapes.