don't assume that you're noise is coming from the power side. Most likely the are AC motors in use on your delivery system. just a thought that it is most likely coming from your shielded UT cabling (rg-174 or 58) then the noise gets amplified throught your pulser/amplifier circiut. look into the ut signal with a scope it should be fairly obvious what it is after that. possibly a shield ground to chassis ground would reduce your signal to noise ratio.