Steve Nugent may have pertinent information regarding modifications for your well regarded JC1s.
http://www.empiricalaudio.com/about-empirical-audio/
Ayre is announcing their newly voiced "Twenty" series on page 60 of the 2015 March issue of Stereophile.
Personally, I'm in the speaker replacement camp followed by tailoring any electronics around the new speaker which is usually far less of a factor. At this level in home auditioning should be a must to fulfill your subjective taste.
http://www.empiricalaudio.com/about-empirical-audio/
Ayre is announcing their newly voiced "Twenty" series on page 60 of the 2015 March issue of Stereophile.
Personally, I'm in the speaker replacement camp followed by tailoring any electronics around the new speaker which is usually far less of a factor. At this level in home auditioning should be a must to fulfill your subjective taste.