The Electro-Harmonix Q-Tron Plus Envelop Control Filter Pedal is essentially the same design as the original Q-Tron but with extremely useful Effects Loop and an Attack Response Switch.
The Effects Loop gives the musician the ability to place an additional effect, or chain of effects between the Q-Tron Plus's preamp and filter section without changing the envelope drive. This is particularly important with most distortion devices, as most all do not have much of an amplitude envelope. The FX loop will also fire up your creative juices to try all sorts of combinations in the effects loop: try the Micro POG into a Deluxe Memory Man. You can invent all sorts of novel effects.
The added Response Switch selects between a slow, smooth, vowel-like attack and the fast, snaked response of the original Q-Tron.
Dedicated effects loop allows you to place any effect or pedal board into the loop
FX send and return without changing the envelope drive
Selectable low pass, band pass and high pass filters
Resonant peak control to adjust the filter's Q from subtle to dramatic
Response switch changes the reaction time of envelope follower from fast to slow
Switchable hi or lo frequency sweep ranges
Adjustable gain knob and boost switch
Sweep direction switch for up or down filter sweeps
Tough and compact die-cast chassis
24DC-100 power supply included
Dimensions in inches: 4.75 (w) x 5.75 (l) x 2.5 (h)