Oscillation and grounding?

[Stevo]

Why is it some pedals work good on the bench very high gain....and than you put them in a metal box and wham oscillation out of control...kind of makes it hard to tweak a pedal than install it to find this :x  :x ...Secondly does putting a box on the board help with noise like it sounds like a ground problem...you can hold the volume pot and it is quite...I think this is common for many pedals with ground noise to quite up installed in a box....Two part discussion here but putting it in the box is the most tedious and you want to know its is right before you start :cry:  Do many have this too???

[R.G.]

Why is it some pedals work good on the bench very high gain....and than you put them in a metal box and wham oscillation out of control...kind of makes it hard to tweak a pedal than install it to find this Mad Mad ...

Mother Nature is trying to teach you about the effects of capacitance from boards and wires to and from metal cases. Out where everything is spread out, the electronic emanations from pcb and wires can radiate away. In a box, you crumple those wires up close to each other. Metal boxes can actually conduct feedback currents. Did you think Mother was being unfair?

Secondly does putting a box on the board help with noise like it sounds like a ground problem...you can hold the volume pot and it is quite...

That is a grounding problem. Touching the volume pot case grounds the case. Run a ground wire up to the pot case. And yes, a metal box will help that, if and only if you ground the metal case.