Unlike graphic EQ, which usually only let you boost a certain frequency, the Boss PQ-4 lets you set the frequency as well as boost the level of that frequency.
These were only made from 1991 to 1997, making them rather rare.
Amazing pedal in great condition - will ship with original packaging and accessories. From Sweetwater: "The brains and brawn of the award-winning Helix family comes to a board-friendly 3-switch stomp in the Line 6 HX Stomp. The HX Stomp makes the… Central Austin
Amazingly versatile pedal in excellent condition. From Reverb: "A pairing of JFET and IC analog channels sits at the center of the Chase Bliss Audio Brothers, a mile-high tone stack packing six individual overdrive, boost, and fuzz circuits. Created in… Central Austin
The Feedback Loop IN DEPTH: The feedback loop is where some amazing stuff happens. To insert an effect into the loop, simply connect a cable from the Send of the loop to the Input of an effect, then connect a cable from Output of the effect to the Return… Central Austin