Type: Two channel mixer preamplifier
Gain: 81 dB (may be reduced approximately 14 or 28 dB with gain switches)
Monaural: +18 dBm (6.15 volts) with
600 ohm line
Unbalanced Line: +7.5 dB (1.83 volts)
Link: +4 dB (1.23V) at rated
output (no load)
Frequency Response: ±1 dB from 20 Hz to 20 kHz
Distortion (THD): Less than 0.25% from 20 Hz to 100 Hz; less than 0.05% from 100 117 to 20 kHz at +10 dBm (2.45V)
Input Impedance: 150/250 ohms nominal
Line Input: 40 dB, 15 kf2
Balanced 600 ohms (transformer
Monaural: isolated output)
Unbalanced Line: 2,000 ohms
Link: 2,000 ohms
Hum and Noise: -128 dBm EIN (150-ohm termination) Channel In to Link Out (from 20 Hz to 20 kHz)
Input: 2 XLR-type receptacles (F) Balanced
Monaural Output: 1 XLR-type receptacle (M) Unbalanced
Line Output: 2 standard 'i+" phone jacks Link: 2 standard ','a " phone jacks Battery: 3-terminal, barrier type
Controls: 2 mixer gain potentiometers 1 BASS control, ±12 dB 1 TREBLE control, ±12 dB 1 MASTER volume control 1 POWER on-off switch
2 Line/Mic switches (internal) 1 high pass filter (250 Hz) per channel, 6 dB/octave (internal)
1 low pass filter (5 kHz), 6 dB/octave (internal)
Gain selection switches for preamplifier gain of 56 dB, 40 dB or 26 dB (internal) 2 phantom power (15 Vdc) switches (internal) 1 tone defeat switch (internal)
Requirements: 100/120/_>00/220/240 Vac, 50/60 Ht or - 24/28V clc
Temperature Range: Up to 55°C (131°F) ambient
Dimensions: 1'/a" H x 19" W x 8" D (4.45 cm H x 48.26 cm W x 20.32 cm D)
Weight: 7.5 pounds (3.41 kg)
Enclosure: Rack mount chassis with heavy duty front handles
ARCHITECT'S AND ENGINEER'S SPECIFICATIONS
The mixer preamplifier shall be a two channel unit with controls on the front panel. Both inputs shall be internally switchable for microphone or line sources. They shall have a balanced and transformer-isolated monaural output for 600-ohm loads. Additionally, an unbalanced line-level output shall be provided for each channel. Link connectors shall be provided to connect the unit to additional 1689A, 1692A, and 1699A mixer preamplifiers.
The mixer preamplifier shall meet the following performance criteria. Gain: 81 dB. Balanced monaural output: +18 dBm with 600-ohm line. Unbalanced line-level outputs: 7.5 dB. Microphone input impedance: 150/250 ohms nominal with balanced input. Line input: 40 dB, 15 kS2. Load impedance: 600 ohms with monaural transformer isolated output, and 2,000 ohms with unbalanced line output. Noise level: -128 dBm equivalent input noise. Frequency response: +1 dB from 20 Hz to 20 kHz. THD: less than 0.25% from 20 Hz to 100 Hz; less than 0.05% from 100 Hz to 20 kHz at +10 dBm.
The mixer preamplifier shall be 13/a" H x 19" W x 8" D and shall weigh 7.5 pounds.
The mixer preamplifier shall be the ALTEC LANSING Model 1689A.