Thanks everyone.
After you remove the filter components, you may notice more noise or "static". You can try replacing the 4558 for a NE5532 if this is a problem, it should work as a direct replacement (although it will need bypass caps if none are currently fitted).
I don't know what bypass caps are...
A bit of noise is OK as long as its not to loud. So, your saying all I got to do is take off R13, R14 and the two green capacitors below them? and where would the resister go? just saying if thats (R13, R14 and the two green capacitors below them) is accurate. And what Oms resisters should I use. Potentiometer maybe?