GT2 whistle

[hari]

I success building Sansamp GT2 base on Tonepad layout, but I found that the rotary switch number 2 have noise..like a whistle..

I used TL072 for all the ICs, some says that for Ics number 2, 3, 4 should use TLC2262...but Its very expensive here...is there any other IC that can be used to replace TLC2262 and solve my problem of noise and whistle..or maybe it because of bad parts or bad solder??? 

BTW, GT2 is high gain pedal..good for metal..

thanks