Life Labs built a pad type instrument in 1957. This instrument came in contact with the body through pads and delivered the frequencies to the body. Dr. Rife was very skeptical about this new instrument built by John Crane and John Marsh because it did not have an RF carrier frequency like the AZ-58.

Because of this the power level on the output was only about 1/5 of 1 watt (0.20 of 1 watt) He had every reason to be skeptical about it. The pad instrument at this time did not have any track record behind it. It would take several years of testing before they would really know if it would work as well as the AZ-58.

The AZ-58 had an (RF) radio carrier frequency that carried the square wave audio frequencies deep into the cells of the body. The pad instrument was developed from a standard off-the-shelf frequency generator which had no radio frequency carrier. Time eventually showed that the pad instrument, without the carrier frequency, did work quite well but it just was not powerful enough.

With the use of an RF carrier frequency the power of a pad instrument can be increased from 1/5 of 1 watt to 10 watts. With the RF carrier frequency the audio frequencies can penetrate the cells of the body. Without it the audio frequencies will only go through the connective tissue in between the cells. For more information on this read the paper “Skin Effect and Bio-Electrical Impedance Analysis” published inside this site. Dr. Robert P. Stafford who used the AZ-58 said he preferred the power of the AZ-58 because he got better results. He achieved better result with the AZ-58 because of the RF carrier frequency.