Affirm icon

0% APR financing

For a limited time, choose Affirm at checkout with monthly payments from 0% APR.

Payments as low as $64/month View offer details

View More From 0%

Few equalizers enjoy the respect and admiration of the coveted API 550A. Designed by the now-legendary Saul Walker in the late '60s, the discrete 550A was first used as a modular OEM equalizer. As the industry rapidly embraced the sonic quality of the 550A, it quickly found its way into many custom console designs by Frank DeMedio and other leading engineers. Many of these consoles are still in use today.

 

Forty years later, the 550A remains the standard against which other EQs are measured, and it has played a major role in the recording industry for decades. Still copied but never duplicated, the 550A became API's standard channel module EQ when the company began manufacturing consoles in 1971. With virtually all existing units spoken for, popular demand for this EQ resulted in API finally resuming production in 2004.

The 550A provides reciprocal equalization at 21 points in 7 steps of boost to a maximum of 12dB of gain at each point. The fifteen equalization points are divided into three overlapping ranges. The high and low frequency ranges are individually selectable as either peaking or shelving, and a band-pass filter may be inserted independently of all other selected equalization settings. Frequency ranges and boost/cut are selected by three dual-concentric switches, and a pushbutton "in" switch allows the EQ to be silently introduced to the signal path. A small toggle switch is used to insert the band-pass filter into the 550A.

The combination of Walker's incomparable 2520 op amp and his "Proportional Q" circuitry gives the 550A user an uncomplicated way to generate acoustically superior equalization.

With the long-awaited reissue of this unit, an EQ that has had such a part in the history of recording is continuing to make history in today's music.

Features

  • 3 bands of classic API equalization
  • Each band offers 7 API selected frequency centers
  • Reciprocal and repeatable filtering
  • Maximum 12 dB of boost/cut per band
  • EQ Band 1 and 3 offer shelf/peak switching
  • "Proportional Q" narrows filter Q at extremes
  • Traditional API fully discrete circuit design
  • High headroom +30 dB clip level

Product Specs

Condition:
Brand New (New)
Brand
API
Model
550A 500 Series 3-Band Equalizer Module
Finish
Black
Categories
Equalizers, 500 Series
Year
2010s
Made In
United States

About The Seller

Pro Audio Design
Joined Apr 2017
Hanover, MA, United States

Accepted Payment Methods

Shipping Policy

Ships from Hanover, MA, United States to:

Continental U.S.
$0.00
Everywhere Else
$100.00

I will ship with tracking to the listed regions. To negotiate shipping rates to other locations, please send me a message.

Tax Policies

This shop collects taxes in the following regions:

Massachusetts
Alabama*
Arizona*
Connecticut*
District of Columbia*
Iowa*
Minnesota*
New Jersey*
Oklahoma*
Pennsylvania*
South Carolina*
South Dakota*
Washington*
Wyoming*
*State sales tax is required in this region. Learn More

Return Policy

Return Window

This product can be returned within 14 days of receipt.

General Terms

Items must be returned in original, as-shipped condition with all original packaging and no signs of use. Buyer assumes responsibility for all return shipping costs unless the item was not received as described.

Refunds

Buyer receives a full refund in their original payment method less any shipping costs.

Message Seller

Accepted Payment Methods

Credit Card
Reverb Bucks
Paypal
Affirm

Limited time offer: Rates from 0% APR
As low as $64/month

Pro Audio Design

Hanover, MA, United States
Joined: Apr 2017

Seller Achievements

API 550A 500 Series 3-Band Equalizer Module
$1,135.25
+ Free Shipping