TB550A Equalizer

Projects > TB550A Equalizer

This DIY 550A from Brian Horvitz is a clone of API’s classic, 3-band equalizer. Horvitz’ design departs slightly from the original in order to use commonly available, modern components. Kits and PCBs will most likely be offered within 2011.


  • Accepts all standard-footprint discrete opamps
  • Uses Ed Anderson’s replica of the API 2503 output transformer
  • Does not require custom switches
  • 500-series compatible
  • Employs high-quality WIMA capacitors

Price: Not announced yet

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