API 550B 500-Series Equalizer
The API 550B 500-Series Equalizer is based on their original 550, that was designed in the late '60s. The API 550b is a continuation of the EQ that played a major role in the history of music recording, but with an additional filter band and several new frequencies.
The API 550B 500-Series Equalizer's benefits are most obvious to those who work with EQ on a continuous basis. If major tonal restructuring is required, the extraordinary headroom made possible with API's 2520 Op Amp offers the predictable and warm analog performance, even under duress. With a surprisingly wide range of tonal variations, the 550b is an invaluable and professional audio tool with great flexibility and excellent sonic ability.
Making use of API's "Proportional Q," an innovation designed by Saul Walker in the '60s, the 550b intuitively widens the filter bandwidth at minimal settings and narrows it at higher settings without the need for additional bandwidth controls. This unique feature minimizes the "phase-shift" sound found in many equalizers. In addition, the reciprocal nature of the 550b enables the user to "undo" what has been done previously with exact precision.
API 550B 500-Series Equalizer Features
- Four bands of our famous sounding equalization
- Each band offers seven API selected frequency centers
- Reciprocal and repeatable filtering
- 12 dB of boost/cut per band
- EQ band 1 and 4 offer shelf/peak switching
- "Proportional Q" narrows filter Q at extremes
- Traditional API fully discrete circuit design
- High headroom +30 dB clip level
- Re-issue of 1967 API 550 EQ with an extra band
API 550B 500-Series Equalizer Specifications
- Number of Bands: Four
- Filter Type: "Low" and "High" bands are Peak/Shelf switchable. Low-Mid and Mid-High are peaking type
- Filter Boost/Cut: ±12 dB
- Filter Slope: 12 dB per Octave
- Input Impedance: 18.5 K +4 in, 7.5 K -2 in
- Output Impedance: Less than 75 Ohms
- Nominal Levels: -15 to +15 dBu
- Clipping Level: +30 dBu @ ±16 V
- Frequency Response: +0, -.3, 30 to 20 kHz
- Noise: Actual, unw noise,
- Distortion: .07% max, @ +18 dBu Output
- Connectors: 15 position .156sp edge connector
- Power Consumption: ±12/18 Volts/DC,@ 40 ma.
API 550B 500-Series Equalizer Includes
- 550B 500-Series Equalizer
- One year factory service and Five year parts Warranty
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