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.
Features
• Four bands of the 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: FourFilter 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, -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" Deep
Actual Weight: 2.02 lbs.
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
Q & A
Reviews
Protect your investment with the Long & McQuade Performance Warranty
A warranty can be a very important factor when making a buying decision. Because repairs can be very expensive in terms of parts and labour costs, manufacturers usually only provide one year limited warranties that generally only cover items that malfunction due to a manufacturer’s defect. With an important purchase such as a musical
instrument or piece of studio gear, however, many people want to have the peace of mind in knowing that their investment will be protected should the product no longer be performing at 100%.
Because of this, Long & McQuade provides our customers with a FREE one-year Performance Warranty on most of our products. The Long & McQuade Performance Warranty supplements the manufacturer’s warranty to ensure that our customers receive complete “no hassle” warranty coverage within their first year.
How does the Long & McQuade Performance Warranty differ from most manufacturers' warranties?
- Performance Guarantee: Normal wear and tear is covered, so your product will be performing as well as the day you purchased it for the entire duration of the coverage. Band and Orchestral Performance Warranty does not include replacing pads or cleaning for woodwind instruments, unless deemed necessary by our repair staff. Ultrasonic cleaning for brass instruments will be provided if deemed necessary by our repair staff, but is not routinely offered under the Performance Warranty.
- Product Replacement: If your product cannot be fixed or costs too much to fix, we will replace it with the equivalent model for no additional charge. If this is not possible, a full refund will be provided.
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Long & McQuade reserves the right to restrict the purchase of additional years of Performance Warranty. Used products come with a 3-month Long & McQuade Performance Warranty. Some products (i.e. computers, software, cymbals and other items) are covered only by the manufacturer‘s warranty. Consumables (i.e. strings, reeds, drum sticks, batteries, tubes, cross faders) are excluded as they are designed to be replaced. Cosmetic Damage, Accidental Damage, or problems caused by Humidity or Temperature Issues are not covered. Speakers damaged by overpowering are generally not covered. Our coverage does not provide compensation for loss of use. As of June 2018 the Performance Warranty is no longer transferable. The warranty is only valid in Canada.
Purchasing additional years of coverage
Some manufacturers provide warranties for longer than 1 year; however, these are usually limited warranties that do not provide the same coverage as the Long & McQuade Performance Warranty. Customers interested in more complete and convenient (but not necessarily longer) coverage are still able to purchase additional years of the Performance Warranty.
If you are interested in receiving this coverage for longer than one year, you have the option of purchasing additional years of the Performance Warranty. The pricing is as follows:
- NEW products: 4% of the current new selling price to double the warranty from 1 year to 2 years. 4% for each additional year.
- USED products: 4% of the current new selling price to increase the warranty from 3 months to 1 year. 4% for each additional year.
- GUITARS: 4% of the current new selling price to double the warranty from 1 year to 2 years. 4% for each additional year. $45 maximum. An additional free setup is not included with additional purchased years of Performance Warranty.
- BAND and ORCHESTRAL instruments: 4% of the current new selling price to double the warranty from 1 year to 2 years. 4% for each additional year.
Great Additions
Reserve in Store
| Product | SKU | Qty |
|---|---|---|
| 550b Discrete 4 Band EQ | 156231 |
