Ampex 351 Owners Manual

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SECTION 1

DESCRIPTION AND PERFORMANCE
CHARACTERISTICS

GENERAL

The AMPEX Series 351 Magnetic Tape Re-
corder/Reproducers are high quality precision
instruments designed for the professional user
who requires the finest and most faithful re-
cording and reproduction.

A basic recOrder/reproducer in the 351 series
consists of a tape transport for operation at
tape speed pairs of 3% inches per second (ips)
and 71/2 ips or 71/2 and 15 ips; a head assembly
for use with the Mi-inch magnetic tape; and an
electronic assembly which contains the record
amplifier, reproduce amplifier, bias and erase
oscillator, and power supply - all featuring
etched board construction.

NOTE

This manual is primarily intended for
recorders using Ampex Catalog Num-
ber 30960 electronics. In instances
where there are significant differences
between this electronics assembly and
earlier models using Catalog Number
30750 or 30950 electronics an appro-
priate notation will be found.

Head assemblies for either full (single)
track, half track or two track stereophonic
(351-2) operation are available.

CCIR equalization can be obtained on request

1-1

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when ordering equipment.

Several mounting arrangements are offered
-console, two case portable, and rack mount.

Tape Width
Tape Speed Pairs

Frequency Response

Signal-to-Noise Ratio

Flutter and Wow

Recording or
Reproducing Time

(NAB 101/2 Inch Diameter
Reels, 2400 feet of tape)

Starting Time

Stopping Time

Reproduce Timing
Accuracy

Rewind Time

In the portable equipment, one case contains
the tape transport and the other houses the
electronic assembly.

PERFORMANCE CHARACTERISTICS

V4-inch
3%-71A2 ips
71/2-15 ips
Speed (ips) Response (Cycles per second)
3% :2 db 50 to 7,500
71/2 :2 db 40 to 10,000
:4 db 30 to 15,000
15 :2 db 30 to 15,000
Speed (ips) Peak Record Level to
Unweighted Noise (db)
3% 50
71/2 60 full track
55 half track or two track
15 Same as 71/2 ips

Peak record level is that level at which the overall (input to output)
total rms harmonic distortion does not exceed 3 percent when
measured on a 400 cycle tone. Noise is measured when erasing
a signal of peak recording level in the absence of new signal. Bias,
erase and reproduce amplifier noise are included in the measure-
ment. All frequencies between 50 and 15,000 cycles are measured.

Speed (ips) Flutter and Wow
(percentage rms)
33/4 2.5%
7V2 .2 %
15 .15%

Flutter and wow measurements include all components between
0 and 300 cycles using an rms value of constant amplitude sine
wave flutter.

Half Track Full Track

Speed (ips) (hrs) (min) (hrs) (min)
3% 4 l 6 2 8
7V2 2 8 l 4
15 1 4 32

The tape is accelerated to full speed in less than 1 / 10 of a second.

When operating at 15 ips, the tape moves less than two inches
after the STOP button is pressed.

Accuracy Accuracy Length of Recording
(percentage) (second) (min)
: 2% :3.6 30

Approximately 1 minute for a full 2,400 foot NAB reel.