Ok it appears that my op-amp cover was put on in correctly.
for oop-amp cover you mean the op amp socket? something like this:
www.atomsindustries.com/assets/images/items/1055/1055.jpg
The op-amp socket is just there in case you want to try or change the op-amp, is not 100% needed, it is just a cool feature.
I saw that you are using an external power supply, have a look at this if you didn't read it yet, just in case...:
www.electrosmash.com/forum/pedalshield-m...ing-pedalshield-mega
Also adjusting the VR1 resistor helps to improve the Signal/Noise ratio. It can make the signal much bigger than the background noise. Make sure that the input signal gets as loud as possible without clipping.
How much noise is expected?
A low-level background hiss could be heard but should be very small compared with the guitar signal.
Make sure that you dont have ground loops, sometimes pluging the pedal close to the amp plug helps.