The FreakzEQ is the EQ portion of the Son of Kong, which is built by Midget Sloatman, and is reported as (and from what I can tell based on the few hints of the original circuit I’ve been able to deduce) a very slightly tweaked version of the parametric EQ circuit that Sloatman designed to put in Frank’s guitars (namely two in his performance Strat, one in the Hendrix Strat, and one, previously two in the d’mini strate, among others. Frank used these internal Sloatman EQs completely differently from the Harmonic Energizer.
While Frank used the Harmonic Energizer as a nasally cocked-wahish overdrive tone, he used the Sloatman EQ as a careful tone shaper or as a feedback enhancer— he would tune the frequency to the resonance of the spot on stage where he’d be soloing most, set the Q to be as narrow as possible, then set the gain to the point where it would give wolf-tone like howling with all the strings lightly damped, and then set it back just a few dB from there, and then open the q back out until it would provide an equal amount of controlled feedback on most notes. This is sort of how he would have gotten that effortless singing feedback with a relatively clean tone on Zoot Allures and most of his live solos from the 80s
