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Everything In Music Since 1958
Everything In Music Since 1958

API 550b Discrete 4 Band EQ

Original price $1,295.00
Original price $1,295.00 - Original price $1,295.00
Original price $1,295.00
Current price $1,230.25
$1,230.25 - $1,230.25
Current price $1,230.25
► New - ♫ In stock
Condition: New
About Inventory Status


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█ Sold out: We don't think we can get this item because it was either discontinued by the manufacturer or was limited in quantity. If you want or need this item call or text us. Sometimes we can help you track down the item through other sources or help you find something similar.

About Item Conditions


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Call or text us at 301-946-8808.

New: The item is brand new as received from the manufacturer with a full manufacturer warranty. Instruments such as guitars, snare drums, drum kits, brass and woodwind instruments may be opened for photography and quality control inspection and may not be in a factory sealed box.

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Used: The item is used. These item may have varying degrees of wear. Please read the description for information about the condition of the item. Used items do not carry a warranty.

B or C Stock: Factory refurbished. These items were purchased from the manufacturer in a refurbished condition. They will show some cosmetic issues, but nothing that would impact performance. Being that these are sealed from the manufacturer, we generally do not open these to photograph the cosmetic issues. They are guaranteed to work and may have a limited warranty or you may purchase an extended warranty in some cases. Please see the listing description for item specific information.

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Get A Perfect Installment To Your Workstation With The API 550B Discrete 4 Band EQ

Based on API's original 550 from 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. Incorporating API's exclusive circuitry and proprietary components (such as the legendary API 2520 Op Amp), the 550b artfully blends the past with the present. So many hit records still depend on the unique 550 sound that engineers around the world find it to be an invaluable tool. In fact, the 550b design has been taken from the original blue prints and spec control drawings from the API archives. It is unlike any other EQ you will ever use.

Rather than offer a huge assortment of complex features, the API 550b provides exactly the right number of controls. Its four EQ bands are overlapped significantly to aid in dual roles as problem solver and sweetening device with each band offering seven switchable filter frequencies that span four-to-five octaves. These frequencies, purposely selected to be musical rather than numeric, were selected by an experienced who's who list of the industry's most proficient engineers.

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.

The benefits of the API 550b 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.


  • 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


SPECIFICATIONS:

  • Number of Bands: Four
  • Filter Type: Low and High bands are Peak/Shelf switchable. Low-Mid and Mid-High are peaking type
  • Filter Frequency Centers
    • Low: 30, 40, 50, 100, 200, 300, 400 Hz
    • Low-Mid: 75, 150, 180, 240, 500, 700, 1 kHz
    • Mid-High: 800, 1.5K, 3K, 5K, 8K, 10K, 12.5 kHz
    • High: 2.5K, 5K, 7K, 10K, 12.5K, 15K, 20 kHz
  • 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, -98 dBu, 20 Hz - 20 kHz
  • Distortion: .07% max, @ +18 dBu Output
  • Connectors: 15 position .156 sp edge connector
  • Power Consumption: ±12/18 Volts/DC,@ 40 ma.
  • Size: 1.5 x 5.25 x 7.5 inches / 38 x 133 x 191 mm
  • Size (Boxed for Shipping): 4.5 X 6.25 X 10 inches / 114 x 159 x 254 mm
  • Actual Weight: 2.02 lb / 0.92 kg
  • Shipping Weight: 2.43 lb / 1.1 kg

Manufacturer: Automated Processes Inc
Model: 550B
SKU: I301386-2-WHXB


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