Relays seldom made a noise in and of themselves so it would not be the first place I'd be looking. What kind of noise? What analysis exactly? If a pop it might be DC where it shouldn't be. If a hiss you may have a bad component.
The relay can best be tested out of circuit using a power supply to operate the coil and using the continuity range on the meter to check the contacts. This will tell you if the contacts are working and low resistance.
PS: I just found your other thread. This only happens on the clean channel. I'd suspect C3 i.e. the cap that feeds the clean volume pot.