TL071 help

[Seljer]

Is R2 the 500k pot and R1 the 2k2 to ground ?

yes

Do You mean increasing the 2k2 will cut the highs on higher gain settings ?

Increasing the 22pF capacitor will cut more of the highs on higher gain settings.

Increasing the 2k2 will lower the maximum gain availble without consequences to the high frequencies (as the high end roll off is all happening between the 500k pot and the 22pF). Decreasing it will give you more gain.
Increasing the 500k will also increase the maximum gain available. Be aware that if you have a loud guitar, your setup with the opamp as it is on its own has probably got enough gain to already the clip rails of the opamp itself when maxed out,

Descreasing the 2.2uF capacitor will remove some of the low end prior to clipping, regardless of what the gain is set to (if you think the low notes are "farty" or overpower things this might help)

[mat]

Seljer, BIG thanks for Your explanation 

I'll get back to the build after a week. Will report how it turns out with bigger cap in there,

Mat

Is R2 the 500k pot and R1 the 2k2 to ground ?

yes

Do You mean increasing the 2k2 will cut the highs on higher gain settings ?

Increasing the 22pF capacitor will cut more of the highs on higher gain settings.

Increasing the 2k2 will lower the maximum gain availble without consequences to the high frequencies (as the high end roll off is all happening between the 500k pot and the 22pF). Decreasing it will give you more gain.
Increasing the 500k will also increase the maximum gain available. Be aware that if you have a loud guitar, your setup with the opamp as it is on its own has probably got enough gain to already the clip rails of the opamp itself when maxed out,

Descreasing the 2.2uF capacitor will remove some of the low end prior to clipping, regardless of what the gain is set to (if you think the low notes are "farty" or overpower things this might help)