Problem with ibanez Flanger 301 from tonepad

[Rumite]

Hello! I've finished the Flanger 301 from Tonepad (http://www.tonepad.com/getFile.asp?id=49)
Problem is a hi-frequent whistling/squeal when I rotate regen knob more than a third resistance of pot.
I changed TL022 -> TL072 and 2N5087 to BC560c (I rotate it of course).
I try to change resistance of VR103, but with squealing flange effect decreases too
Also I can't found scheme of this circuit — in original Ibanez scheme IC's pinouts is another.
Maybe anyone have scheme of this layout or faced with the same problem? Sorry for my bad English. Thanks.

P.S.:
I try to test this layout with audio probe, and squealing was not only on this circuit (without flanging too)