These two effect modules are not actually "guitar" effects per say, but rather synth modules that will work on anyanalog signal. The input and output impedances may need altering depending on your needs. The high frequencybrightener is nothing more than a simple treble booster with a gain control (1k) and an intensity control (5k). Theall signal brightener, however, has a seperate control for brightening the low end (100k*) as well as the high end ofthe frequency spectrum (100k**). The 10k trimmer is a set and forget type adjustment. Set it so the circuit breaksinto oscillation, then back up the setting to the point where the oscillation just stops. These two modules wereexcerpted from Music Synthesizers - A Manual of Design and Construction by Delton Horn; TAB Books, 1984.