Altec 780a 1780at pre amplifier
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Page 1
ALTEC
1780A AND 1780AT
MIC/LINE INPUT MODULE
DESCRIPTION
The ALTEC LANSING 1780A and 1780AT Mic/Line
input modules combine basic microphone
preamplification with true line level input capabili-
ty. Each module has a built-in resistive pad to per-
mit levels in excess of +10 dBm and their high
input impedance easily allows sixteen modules
to be driven from a single low impedance source.
In addition, both modules have a 300 Hz high pass
filter, phantom power capability, L + R stereo
SPECIFICATIONS
(Reference 0 dBu = 0.775 v rms)
Gain: 0 dB - 50 dB, continuously variable
Input Sensitivity:
Without pad -58 dBu to -8 dBu
(1 mv rms to 312 my rms)
-38 dBu to +12 dBu
(10 mv rms to 3.12 v rms)
VWth pad
Input Impedance:
1780A 10 kn
1780AT 10 k0
With 1793
Dual Phono 40 k0
Frequency
Response: 50 Hz - 20 kHz, ii dB
25 Hz- 40 kHz, i3 dB
Total Harmonic
Distortion:
(Ref. minimum gain, 50 Hz-20 kHz measurement
bandwidth, 30 kHz low pass filter)
1780A <0.01°/o
1780AT < 0.025%
summing, and from 0 to 50 dB of continuously
variable gain. They are 100% compatible with all
WOO-series mainframes and accept any one of the
1790~series connectors. The A'ilversion includes a
10 kn input bridging transformer for those who
prefer transformer isolation. Unlike the 1781A,
neither has muting (priority or slave), remote
volume control capability, or continuously-variable
high and low cut filters.
Equivalent Input
Noise: <-120 dBr
(Ref. 0 dBr = 100 mv rms output, 10 kn load, 200
input termination, maximum gain, A-weighted)
High Pass Filter:
Corner frequency: 300 Hz
Slope: 12 dB/octave
Controls: 1 - Gain, continuously variable
Weight (N81):
I780A 2.5 oz. (70 gr)
1780AT 3.0 oz. (85 gr)
Power Supply
Requirements: :18 VDC at 15 ma DC
(Supplied by mainframe)
Included
1- 2-pin female jumper
(for phantom power)
2 - mounting screws
(for potentiometer bracket)
1 - Operating instructions
Accessories:
Q
J
Page 1
ALTEC
1780A AND 1780AT
MIC/LINE INPUT MODULE
DESCRIPTION
The ALTEC LANSING 1780A and 1780AT Mic/Line
input modules combine basic microphone
preamplification with true line level input capabili-
ty. Each module has a built-in resistive pad to per-
mit levels in excess of +10 dBm and their high
input impedance easily allows sixteen modules
to be driven from a single low impedance source.
In addition, both modules have a 300 Hz high pass
filter, phantom power capability, L + R stereo
SPECIFICATIONS
(Reference 0 dBu = 0.775 v rms)
Gain: 0 dB - 50 dB, continuously variable
Input Sensitivity:
Without pad -58 dBu to -8 dBu
(1 mv rms to 312 my rms)
-38 dBu to +12 dBu
(10 mv rms to 3.12 v rms)
VWth pad
Input Impedance:
1780A 10 kn
1780AT 10 k0
With 1793
Dual Phono 40 k0
Frequency
Response: 50 Hz - 20 kHz, ii dB
25 Hz- 40 kHz, i3 dB
Total Harmonic
Distortion:
(Ref. minimum gain, 50 Hz-20 kHz measurement
bandwidth, 30 kHz low pass filter)
1780A <0.01°/o
1780AT < 0.025%
summing, and from 0 to 50 dB of continuously
variable gain. They are 100% compatible with all
WOO-series mainframes and accept any one of the
1790~series connectors. The A'ilversion includes a
10 kn input bridging transformer for those who
prefer transformer isolation. Unlike the 1781A,
neither has muting (priority or slave), remote
volume control capability, or continuously-variable
high and low cut filters.
Equivalent Input
Noise: <-120 dBr
(Ref. 0 dBr = 100 mv rms output, 10 kn load, 200
input termination, maximum gain, A-weighted)
High Pass Filter:
Corner frequency: 300 Hz
Slope: 12 dB/octave
Controls: 1 - Gain, continuously variable
Weight (N81):
I780A 2.5 oz. (70 gr)
1780AT 3.0 oz. (85 gr)
Power Supply
Requirements: :18 VDC at 15 ma DC
(Supplied by mainframe)
Included
1- 2-pin female jumper
(for phantom power)
2 - mounting screws
(for potentiometer bracket)
1 - Operating instructions
Accessories:
Q
J