About a year ago, I traded my GQ SS V-2 to a friend and then last week I got the GQ back. I have been playing with it, trying to brush up on how to operate it and noticed when I adjust the threshold knob, it makes a sharp high pitched squeal for a few seconds, then the tone drops to a normal sound. Is this normal, I can't remember if it did that when I used it the last time, which was a year ago.