API 55-OA
Little is documented about the API 55-OA as a standalone vintage model, and surviving period resources are thin. The record shows a 500-series equalizer module with three bands of peak/shelving EQ. Mix (December 2009, p.29) listed it at a retail price of $1,195, in a product roundup of dynamic and equalizer modules. A later Mix article (May 2013, p.69) mentioned the 55-OA in passing, noting that its only way to shape certain interactions between bands was to add a second EQ to the mix. That suggests fixed or limited parametric flexibility. The module appears to be a discrete design, consistent with API's house style. No full specification sheet, release year, or production run details have been confirmed from the period.
Known details from the available sources:
- Type: 500-series equalizer module
- EQ bands: 3 bands, peak/shelving
- Original price: $1,195 (USD, circa 2009)
- Design: Discrete (consistent with API tradition)
- Manufacturer: API Audio, www.apiaudio.com
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