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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
Inventory Status:

❓ Out of stock
About Inventory Status


Questions?
Call or text us at 301-946-8808.

In stock: It is in stock and available to ship or pickup. We can usually ship or have these items available for pickup by the next business day if they don't require inspection, special handling, or setup. Our pickup location is 11151 Veirs Mill Rd. Silver Spring, MD 20902.

📆 Preorder: It is on the way to our warehouse. We can't predict when preorder items will arrive due to current supply chain issues. If you place an order for one of these items someone will contact you to estimate the delivery date.

Out of stock: We don't currently have it available but you're not out of luck yet. We still may be able to get it. If you order one of these items we will contact you with an estimated fulfillment date. You have the option to cancel the order if you change your mind.

Special order: The item is so special that it needs to be custom ordered for you. Some of these items are works of art and have to be made individually. Orders for special order items must be prepaid and we cannot accept cancellations or refunds.

█ 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


Questions?
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.

Mint or Open Box: The item may have been opened and tested but has been repackaged. The original packaging may have superficial issues but the item itself and any originally included accessories are in perfect, like new condition.

Display Model: These items are so cool that we put them on display in our legendary shop. The condition is brand new as received from the manufacturer with manufacturer warranty. Rest assured, these items undergo a very careful inspection before shipping.

Demo: These items have been on our sales floor for demo purposes and will likely show signs of use. The original packaging may no longer be included, but you can be assured that you are receiving an awesome item and an awesome price.

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.


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, 400Hz. Low-Mid: 75, 150, 180, 240, 500, 700, 1Khz. Mid-High: 800, 1.5K, 3K, 5K, 8K, 10K, 12.5K. High: 2.5K, 5K, 7K, 10K, 12.5K, 15K, 20K
  • 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, 20-20 kHz
  • Distortion: .07% max, @ +18 dBu Output
  • Connectors: 15 position .156sp edge connector
  • Power Consumption: ±12/18 Volts/DC,@ 40 ma.
  • Size: 1.5 X 5.25 X 7.5 Inches
  • Size (Boxed for Shipping): 4.5 X 6.25 X 10 inches
  • Actual Weight: 2.02 lbs.
  • Shipping Weight: 2.43 lbs.

Manufacturer: Automated Processes Inc
Model: 550B
SKU: I301386-N-0-WHXB


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