The Tesla Violet Ray could be likened to an analog Rife machine with a plasma tube, only the frequency is not able to be set at all and varies somewhat. Most modern Rife machines are digital and can output a user controlled specific frequency.
I found some stats on the modern Violet Ray:
peak output voltage: 17.5kV
output frequency: 444kHz with no load (down to 90kHz with "human load")
average output current: 45mA
peak output current: 480mA
average output power: 4.5W (pure RF)
output pulse energy: 1.5mJ
So it outputs high frequencies but they vary depending on what its in contact with. I bought one after a user had been posting about
their experience with it on another forum. You can find them for only $25 on Ebay.
They really seem to have an amazing effect of encouraging cells to detox. All our cells try to maintain a certain charge across their membrane. By stimulating them with electromagnetic frequencies cells can detox or heal faster. For example PEMF (similar concept but using a magnetic coil) is FDA approved for healing bone fractures.
Here's the mega thread on the Violet Ray:flash.lymenet.org/ubb/ultimatebb.php/topic/1/131235