Cap size does matter!

Small capacitors can make your tattoo machine run
faster. Not small size, but small rating in the micro farads.
This is because they recharge like a battery, and
are filled with some type of material that can store electricity.
When they are recharged they will burst their
stored energy to the circuit. The smaller the rating then
the smaller the battery size, and the quicker they will
fill and release. If you put a bigger cap on your machine
then it will take longer to store the energy, but it
will have that extra reserve juice to kick in when you
are bogging down the machine with additional pressure.