It provides reciprocal equalization at 15 points in 5 steps of boost divided into three overlapping ranges. The high and low frequency ranges are individually selectable as either peaking or shelving, and a band-pass filter can be inserted independently of all other. The 550A is a uniquely powerful equalizer with that one-of-a-kind API sound.
•5 selected frequency centers per band
•Reciprocal and repeatable filtering
•Maximum 12 dB of boost/cut per band in 2-3 dB steps
•”Proportional Q” narrows filter Q at extremes
•High headroom +30 dB clip level
•HF Filter Gain -12dB to +12dB
•HF Filter Frequency 5KHz, 7KHz, 10KHz, 12.5KHz and 15KHz
•MF Bell Filter Gain -12dB to +12dB
•MF Bell Filter Frequency 0.4KHz, 0.8KHz, 1.5KHz, 3KHz and 5KHz
•LF Filter Gain -12dB to +12dB
•LF Filter Frequency 50Hz, 100Hz, 200Hz, 300Hz and 400Hz
•Filter On/Off 50Hz to 15KHz Band Pass Filter
•LF Filter Type Low Shelf or Bell
•HF Filter Type Hi Shelf or Bell •EQ IN On/Off
•VU Meters -30dB to 0dB With Clip indicator
•Output Controls •Analog On/Off
•Phase Polarity Reverse On/Off
•Output Gain -18dB to +18dB
•Trim Output Gain Adjustment
