The ornamental design for a powersupply for tattoomachine, as shown and described.
FIG. 1 is a perspective view of a power supply for tattoo machine showing my new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side view thereof, the right side view being a mirror image of FIG. 5;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines in the figures are for the purposes of illustrating portions of the power supply for tattoo machine, which form no part of the claimed design.