0% up to 48 Months on over 110 Brands!

New & Current Vintage King Card Holders

$ 1,230 .25
Your Savings: $ 64 .75 Msrp: $ 1,295 .00
No interest if paid in full within 12 months Learn more
In Stock
Orders placed by 4:00pm ET Monday - Friday will ship the same day. To inquire if this item is available to ship sooner or is in one of our stores, please call 888.653.1184 or chat with us.

SKU

781

Please note: this item is available for purchase in the United States only.

API 550b 500 Series Equalizer

Discrete four-band EQ
MFR# 550B

Product Description

The API 550 discrete four-band EQ played a major part in the history of music recording in the USA during the 60s and 70s.  Originally conceived for use in API's consoles, this latest 550 "B" version is a continuation of the original 1967 550 through the 550A with one 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 the 550B will be an invaluable tool you will turn to again and again.  The API 550B—unlike any other you will ever use.

Many EQs today offer a huge assortment of complex features, but the API 550B provides exactly the right number of controls to the professional engineer.  Deceptively simple at first glance, the 550B's four EQ bands are overlapped significantly to aid in dual roles as problem solver and sweetening device.  Each band offers seven switchable filter frequencies spanning four to five octaves, selected through experience by a "who's who" list of the industry's most proficient engineers.  This re-issue design has been taken from the original blueprints and spec control drawings from the API archives.

Making use of "API Proportional-Q", a design introduced by API in the 60's, the 550B intuitively widens the filter bandwidth at minimal settings and narrows it at higher settings—without the need for additional bandwidth controls.  This feature minimizes the "phase-shift" sound found in many equalizers.  The reciprocal nature of the 550B enables the user to "undo" what has been done previously.

The benefits of the API 550B are most obvious to those who work with EQ on a continuous basis.  The 550B's ability to affect or reverse tonal modifications is perhaps the most important feature.  If major tonal restructuring is required, the extraordinary headroom made possible with API's 2520 op-amp offers predictable and gentle "analog" performance under duress.  With a surprisingly wide range of tonal variations, you can do no better than the API 550B.

Features:

  • Four bands of famous-sounding equalization
  • Each band offers seven API-selected frequency centers
  • Reciprocal and repeatable filtering
  • 12 dB of boost/cut per band
  • EQ bands 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

 

Product Specifications

Condition New
Tube or Solid State Solid State
Channels Single-Channel
Chassis Module
Module Type 500 Series
Module Slot Count 1 Slot
Digital I/O No
EQ Type Parametric

Product Reviews

5 out of 5 stars.
Review Count (4)

write a review

This thing sound so good!

By AD T on November 6, 2022

I’ve used the digital version of this EQ for quite some time. I’ve learned as I age that real gear ALWAYS sounds better than the digital emulations. The difference here is noticed while mixing. I bought two 550Bs, one for kick bus, one for snare bus (then both got to API 527A compressors). Both kick and snare are way more present in the mix. They fight their way through and do not get smeared along the way. They just sound magically better. I’ve also tracked acoustic guitar through these. Same thing. More present and in your face. The EQs can nicely get rid of the rumble and the sparkle is the best from any EQ I have. I highly recommend if your looking to get “real” again.

By Nick N on October 27, 2022

No words can say... This thing is super-freqi!!! Will NEVER sell. :-) Drums and bass are a breeze now.

By Roy G on April 22, 2021

I recently bought a 550b to use along side some vintage 550a's. In short, they compliment eachother nicely! The 550a is looser and wider sounding, while the 550b is taller, with a tighter bottom and a bit punchier. Great EQ!

By Andy P on May 1, 2017

* Required Fields

Share Your Opinion

The best gear advice always comes from those who use it the most. That's where you come in! Let the pro audio world hear your voice with a review of the API 550b 500 Series Equalizer . Once you submit your review, please check your email and verify your address to have it posted.

How do you rate this product?
I would like to thank VK for the wonderful sales assistance, service and prices. This was my first purchase with you and it won't be my last. I only wish I'd discovered you years ago!
Matthew R.
I had two Grammy wins this year - Ray LaMontagne & Carolina Chocolate Drops. Both made with help from Vintage King!
Ryan F.
In almost 20 years in Pro audio buying, never did I receive a unit so well packed and exactly as described. Works flawlessly. The whole process has been so smooth. I will never hesitate to do business with you guys in the future and will recommend you to everyone I know.
Martin C.
This was my first experience buying something from Vintage King (although I surf the "used" categories on the website frequently!), and, despite being on the other side of the world, I had absolutely no trouble and everything went very smoothly.
Phil T.
The speed of delivery exceeded my expectations! I was VERY pleased that my shipment arrived in time for a scheduled vocal tracking session. The packing insured that my order arrived safely. And the sales staff responded quickly to questions regarding the product.
James P.
Thank you so much! Vintage King has been so fair and easy to work with. I can't thank you enough. It feels good to trust such a hefty purchase to folks who are so helpful and knowledgeable. Vintage King is a sound designers dream store.
Noa L.
You guys have excellent customer service and I am excited about the next upgrade I complete on my fifth recording facility. I've been in the studio business for forty plus years. The salesman I worked with at Vintage King was the best of the best. You all rock!
Robby T.
I would recommend Vintage King to any one looking for top-class gear, unbeatable customer service and the best prices on the map!
Jake D.
My experience with Vintage King was excellent. The order was here fast considering it was out of stock. The sales person had SKB send it to me directly and I couldn't have been more pleased.
Michael D.
From the minute I placed my order I was kept well-informed through each step in your process. Even though I was buying a comparatively modest piece of gear, your attention to detail made me feel like I was purchasing a six-figure mixing desk.
Thomas W.
I am a new customer of yours. You guys provided me the absolute best deals in ordering all the equipment to power my brand new recording studio. Your customer service is amazing and i will always deal with you from here on out.
Rob M.
Thanks for your great service and getting this out today. You guys really are the Kings!
Alan B.
Better than expected! Truly impeccable service. Your team was professional, knowledgeable, provided speedy delivery above and beyond standard. Vintage King Audio is definitely my go to for all of my audio and information needs.
James O.