I'm wondering if anyone has experience with an Agro pedal producing a high pitch constant feedback sound. Yesterday I ran an active stingray through a compressor and into the Agro. When I turned both the saturation and volume dials past 3/4 turn, the pedal made a high pitched feedback sound. I could eventually balance it out so 1/2 volume and 3/4 saturation did not create the whistling sound. But anything past 3/4 on both and it would whiiiiiiiine like crazy. This wast first time using the pedal. I bought it used. Anyone know if I have a bum pedal or maybe just overloaded it with signal? I thought it should be able to handle the input signal. Thanks in advance for any information/ experience!