ALTEC LANSING Vintage graphic equalizer Model 1431A , 31 Band 1/3 Octave (Mono)

ALTEC LANSING Vintage graphic equalizer Model 1431A , 31 Band 1/3 Octave (Mono)
->This 1431A  has been tested in our workshops
->Includes Owner’s manual
->Includes Service Instructions
->Of course, due to their age, there are scratches here and there, See the photos
->Shipping prices can vary depending on where you are in America
->All our equipment is shipped in boxes with double protection

Description;

Altec Lansing 1431A graphic equalizer Variable Q Active Filter 31 Band 1/3 Octave Equalizer KEY FEATURES • Variable Q filter set • 31 bands of boost and cut • Select between 6 dB or 12 dB of boost and cut KEY SYSTEM SPECIFICATIONS Center Frequencies: 20, 25, 32, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 4 00, 500, 630, 800, 1 k, 1.25k, 1.6k, 2k, 2.5k, 3.15k, 4k, 5k, 6.3k, 8k, 10k, 12.5k, 16k, 20k Hz Maximum Boost/Cut: 12 dB Low-Cut Filter Corner Frequency: 43 Hz Frequency Response at Unity Gain: (High-Pass Filter Disengaged) 20 Hz - 20 kHz, ± I dB Total Harmonic Distortion at Unity Gain: (20 Hz - 20 kHz, 0 dBu Output) < 0.01% Noise at Unity Gain: < -85 dBu, 20 Hz - 20 kHz Maximum Input Level at Unity Gain: + 20 dBu (7.75 Vrms) Maximum Output Level: + 20 dBu (7.75 Vrms) DESCRIPTION The Altec Lansing 1431A is a boost and cut '/3 octave graphic equalizer whose primary use is for tuning the overall frequency response of a sound reinforcement system, both to increase gain-before feedback and to compensate for the deficiencies in the acoustic environment and the sound system. The active Q variable filter set utilized in the 1431A allows effective equalization with few problematic side effects. As Figure 1 illustrates, the filter characteristics vary with the amount of boost or cut used. At low control settings, the filter Q is very wide. As the control is boosted or cut, the filter Qnarrows so that there is minimum interaction between adjacent frequency bands. The filter response is designed to affect a'/:,-octave range. Each of the 31 'V;3-octave filters provide 12 dB of boost or cut at ISO frequencies 20 Hz through 20,000 Hz. The faders have a positive detent in the center, flat-response position. The gain control also has a center detent at unity gain. A low-cut filter switch, with a 43 Hz corner frequency and 18 dB per octave slope, is located on the front panel. A range select switch allows selection of either 6 dB or 12 dB of boost or cut.