The API 550A is a three-band equalizer what was first released in 1971 as part of the company’s modular hardware lineup. Now a certified studio classic, the 550A’s versatile and ability to push settings very hard while maintaining sonic integrity keep it amongst the most widely-used analog EQs today with a legacy spanning well over 40 years.

The 550A was originally introduced to be implemented into custom consoles, as was customary in the 60s and 70s. Its popularity rose rapidly and it became a fixture in the classic API consoles on which many timeless records were made, such as Fleetwood Mac's Rumours. With most vintage units being spoken for after production ceased, demand led to the reissue of the 550A in 2004.

Its simple interface and predetermined frequency points make it an intuitive piece to use, tuned to suit a wide range of musical applications. Its sound is largely characterised by the ‘proportional Q’ response, which tightens the bandwidth of a cut or boost proportionally to the gain applied or removed. This lets the unit gently shape the tone at modest settings or hone in on problem areas when pushed hard.

The 550A excels at adding and enhancing character in instruments and vocals. Heavy-handed EQ moves remain pleasing and musical and drastic tone-shaping will still sound good. To accommodate this, internal headroom of +30dBu allows the full range of the 15dB of gain available with each band to be used without concern of overloading the unit.

The API 550A is a great choice for creating character and tone from the classic API circuity and is an excellent all-round EQ for those looking to withstand from surgical precision or oversaturation.

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