Wah-ing Noise?

[OliveR_FF]

I think you may be interested in something i stubled over not long ago while making a simple tube screamer. I was using a single opamp for the drive stage - the TL071 and for some reason it wasn't working properly. As i increased the gain on the clipping stage there was more and more distortion, as expected but there was also a kind of wah-ing sound going on in the background. After some close inspection i realised that one of the tracks on my veroboard wasn't completely broken and pin 5 (Offset Null) on the opamp was connected to the end of the clipping stage. So i broke the track and it works fine now.

I was wondering if anyone know's what is supposed to happen when you put a voltage in to pin 5?

I do have a sound recording of it happening if your interested but it was done through a amp modeller and they really don't like being overdriven.