Description

The Altec Lansing 1780A/1780AT Mic/Line Input modules combine basic microphone preamplification with true line level input capability. The module has a built-in resistive pad to permit levels in excess of 0 dBu and its high input impedance easily allows sixteen modules to be driven from a single low impedance source. Also, the module offers a 300 Hz high-pass filter, phantom power capability, L + R stereo summing, and 0 to 50 dB of continuously variable gain. Included in the 1780AT version is a 10 kSZ input bridging transformer for those who prefer transformer isolation.

1780A/1780AT Specifications

Gain: 0 - 50 dB, continuously variable

Input Sensitivity:
Without Pad: -68 dBu to -18 dBu
(.3 mVrms to 100 mVrms)
With Pad: -48 dBu to +2 dBu
(3 mVrms to I Vrms)

Input Impedance:
1780A: 10 kSZ
1780AT: 10 kS2
With 1793 Dual Phono: 40 ki2

Frequency Response: 50 Hz - 20 kHz, t 1 dB

Total
Harmonic Distortion: (Ref. minimum gain,
50 Hz - 20 kHz measurement bandwidth, 30 kHz low-pass filter)
1780A: <0.01%
1780AT: <0.025%

Equivalent Input Noise: <-120 dBr
(Ref. 0 dBr = 100 mVrms output, 10 kfl load, 200 fl input termination, maximum gain, A-weighted)

High Pass Filter:
Comer Frequency: 300 Hz
Slope: 12 dB/octave

Controls: I - Gain, continuously variable

Weight (Net):
1780A: 2.5 oz. (70 g)
1780AT: 3.0 oz. (85 g)

Power Supply
Requirements: 18 VDC at 15 ma DC (supplied by mainframe)

Included Accessories: 1- 2-pin female jumper (for phantom power) 2 - mounting screws
(for potentiometer bracket) 1 - Operating Instructions