[HayZee518]

I'm not familiar with your amplifier in particular however if it uses tubes, then what you may be feeling [as far as shocks] go is the B+ voltage on the plates of the tubes. This voltage can be as high as 180 volts DC or higher!. The tube filaments operate at around 6.3 volts. AC is fed from the line into a filament and B+ transformer where it is stepped up and down for its use within the system. It is then fed to a bridge rectifier which changes the AC to DC. A dual diode tube is what changes the AC to DC. Everything in the circuit except for the power supply capacitors should be running "above" ground. The negative of the filtering capacitors are grounded to the case. Essentially everything metal is grounded to the case. If the transformer shorts out or part of its winding shorts to ground it will charge the case to line voltage [ which is dangerous] if you are grounded. there are other components of tube systems which can contribute to your problem. the control grid has a DC voltage on it to vary the amount of electrons that are given off by the filament from reaching the plate which is how a tube can amplify. there's other parts too - a suppression grid etc within the tube.
A leaky filter capacitor can contribute to extraneous sound or crackle.