Note
Ham Radio, Dec 1970, p. 84.
The Ampress is not a speech clipper, but a variable-gain preamplifier that uses controlled negative-feedback to produce a constant output level automatically.
The circuit operates with very fast attack time to accommodate transients. In addition, the Ampress incorporates a "speech enhancement" feature which amplifies voice signals selectively, with frequency response controlled by the compression function. The result is a crisp signal with carefully exaggerated speech harmonics and high-frequency components to punch through heavy QRM.
The Ampress will work with all amateur rigs, AM, AM and SSB, and comes
in two models: the CCA-1 which operates on three AA cells, or the CCA-1R which operates on three rechargeable cells and has an internal current regulator and external AC adapter/charger.