API 550A Discrete 3 Band EQ

1,463.00 (including VAT @ 23%)

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Item available to order

This item is available to order, and we do not currently have the item in stock.

When you place your order, we will request the item from our supplier as soon as possible. We will dispatch this product to you as soon as it is received from our supplier.

"Estimated delivery to you" is our estimate of when we will be able to deliver the product to you, based on our supplier's normal delivery timescales. If we become aware it is going to take significantly longer than normal to deliver this item, we will let you know, otherwise, we will advise by email or text message when the item has been dispatched from our distribution centre.

Estimated delivery to you: 20th December 2016
FREE Delivery available.

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30 day money back guarantee included

30 day money back guarantee included

Once the product is delivered, you have 30 days to decide that you definitely want to keep it. If you decide it is not suitable for any reason, you can return it back to us for replacement or full refund, including standard delivery charges.

All Products are new unless stated, and include a minimum of one year warranty.

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Optional: 3 year warranty: €73.00
(Includes 60 day money back guarantee)


The product price includes a one year warranty and 30 day money back guarantee.

However, the Gear4music extended warranty scheme provides an enhanced service, and is designed to offer a higher level of protection than many 'free' warranties offered by some retailers and manufacturers.

The highlights of this enhanced warranty service are:

  • Warranty is extended to 3 years from the date of delivery.
  • Our Money Back guarantee is extended from 30 days to 60 days (terms apply after 30 days)
  • Collection and delivery costs are included for the first two years
  • Claim 50% cash back on the cost of the policy after 3 years if it has not been used!
  • Warranty is transferable if the item is re-sold
  • Loan or replacement equipment will be provided if the product isn't repaired within 30 days
  • If an item can not be repaired, a similar alternative product or cash discount (as defined in this policy) will be offered
  • The policy can be cancelled within 30 days, and at any time after that for a pro-rata discount

Please note that this extended warranty is currently only available on products sold within the EU or EEA, and is subject to the terms and conditions as detailed on the extended warranty certificate provided.

For customers in outlying areas of the country, the price of the Extended Warranty may be marginally higher, due to the potential for higher collection and redelivery transport costs.

This enhanced warranty is in addition to the standard Gear4music and manufacturer warranty policies, and the Gear4music terms and conditions of trade. No statement or condition of sale contained within these terms affects or restricts your statutory rights as defined under the Consumer Contracts Regulation 2014.

Product Ref: 61727

  • Re-Issue Of The Original Classic
  • ''Proportional Q'' Circuitry
  • Each Band Offers 7 Frequency Centers
  • 2520 Op-Amplifier
  • Reciprocal Equalization At 21 Points

API 550A Discrete 3 Band EQ

The API 550A Discrete 3 Band EQ was designed by API's founder Saul Walker in the late '60s. Re-issued in 2004 by popular demand, the 550A is a classic modular equalizer designed for sound engineers. The classic design and original features help to preserve that vintage, clear sound produced by the original 550A. Providing reciprocal equalization at 21 points in 5 steps of boost to a max output of 12dB of gain at each point. High and low frequency ranges are individually selectable as peaking or shelving and the band-pass filter can be inserted independently of all other equalization settings. With its 2520 Op-Amplifer and ''Proportional Q'' circuitry, this unit delivers optimal sound quality combined with the vintage design, ideal for sound engineers.

Product Ref: 61727

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Full Description

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''Proportional Q'' Control

Saul Walker (the founder of API), designed the ''Proportional Q'' control in the '60s, allowing for the widening of the filter bandwidth at minimal settings whilst narrowing it at higher settings, without the need for additional bandwidth controls. This feature helps to minimise the phase-shift sound found in many equalizer units.

Classic Re-Issue

The 550A was first developed and circulated in the late 60s. Designed by API's founder, Saul Walker, the discrete 550A was used at first as a modular OEM equalizer. The sonic quality and functionality of the 550A was embraced by the industry, finding its way into many custom console designs by many renowned engineers. In 2004, this unit was re-issued by popular demand. The 550A is still as much of a powerhouse equalization unit as it was at its original release.

The API 500 Series

The API 500 Series focuses on high sound quality and longevity at an affordable price range. Considering most studio rigs undergo a large amount of swapping and changing between equipment, the API 500 series is designed to last, from its high quality components down to its rugged and durable design.


  • 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

For more information on the 550A please refer to the PDF above.
Your order may be delivered with a plug adapter
If any electrical items in your order are supplied with a United Kingdom plug connection, a suitable plug conversion adapter will be included free of charge.