My prototype passive EQ was first put into service in January of 2010, which means I probably started building it in December of 2009. In the beginning it was a passive EQ filter with no amplifier for makeup gain, no output transformer and the incorrect input transformer, but even then it sounded great. Since then I have occasionally modified, tweaked, added on and taken away from it, until 2013. In '13 I stared hitting it hard with lots of R&D time of which the most was conducted in the first few months of 2014. Yesterday I finally got the EQ sounding so great its breathtaking, which means I'm done. The actual production model will be somewhat different, but it will be strongly based on the prototype.
About the Author
Mike Congilosi II, Inventor/Engineer