The VQP-258A and VQP-259A plugins are faithful recreations of two entirely passive EQs / filters that were introduced in the 50s. Unlike its competitors from the same era, the 258A offered two widely orthogonal and intuitive controls that were capable of independently cutting or boosting the low and high frequency spectrum, whereas the 259A filter cascade excelled in its wide range of settings.
Using state of the art circuit-modeling techniques a meticulous rebuild of the original 258-A program equalizer was converted into a software emulation that features all the intricacies of the hardware version, including band interaction and inductor/transformer core saturation. An emulation of the 259-A filter cascade was added to allow for cleaning up the low and high ends of your mix where necessary.
Available in VST, VST3, AAX Native, AudioUnits for Mac OS and Windows in 32 and 64-bits.