Now to the point.
To get SRV's tone you should:
-Think about getting similar picks and equipment (YES! picks!)
-The equipment isn't that important, if you gave SRV different equipment his tone would still ring through.
-tone is in the fingers and pick.
-try it, hit an open string with the pick listen to the sound, then angle the pick a little and hit that same open string. The pick angle changed the tone ever so slightly.
-to get SRV's tone you have to work carefully to hit the string the exact same way he does. Which can take a very long time to accomplish.
-The reason changing pick angle and power works is because different angles make certain frequencies within the note louder, therefore changing tone.
(sounds like BS doesn't it)