API 550A 500 Series 3-Band Equalizer

The API 550A is a legendary 3-band equalizer that has shaped the sound of countless hit records since its introduction in the late 1960s. Revered for its musical tone and unmistakable punch, the 550A brings the classic API console EQ into the modern 500 Series format.

With its proportional Q design, the 550A delivers gentle, wide boosts or cuts at lower settings and increasingly focused curves at higher boosts—making it equally powerful for subtle shaping or surgical correction. Each of the three bands offers seven selectable frequency centers, plus switchable high- and low-pass filters for added flexibility.

Powered by API’s discrete 2520 op amp, the 550A delivers the warmth, headroom, and character that engineers worldwide demand. Perfect for tracking, mixing, or mastering, it adds depth and clarity to vocals, drums, guitars, and more.

Key Features

• Classic 3-band EQ with proportional Q design

• 7 selectable frequencies per band for versatile tonal shaping

• Switchable high- and low-pass filters

• Powered by API’s 2520 op amp for signature tone

• Compact 500 Series format—ideal for any API Lunchbox or 500 rack

• Designed for professional studio applications

The API 550A is more than just an equalizer—it’s a piece of recording history that continues to define modern sound.

Condition: New (Full Manufacturer Warranty)
What’s in the box: API 550A EQ module, documentation