hi tom,can i ask you a question as i get no response from the suppliers of my machine,i bought a gb4000 with amp to primarily treat diabetes type 2 and tinnitus,i felt quite good after a trip to a clinic in philli from the uk,and thats what made me purchase a gb4000,after doing various frequencies i dont seem to see any improvement,i try the rf obviously you cant feel it(makes me wonder if my machine is working)when on audio mode i do get pulses through the handhelds,but no pulses on audio @freq 10000 (which is a popular frequency)is this the same on your machine?is there any way i can check the outputs on the handhelds on rf,as i say i am from the uk and bought the gb4000 from the usa off the manufactures i had a problem with the power supplies which they replaced,also have you had any success with diabetes type 2 or tinnitus,i have heard so much about the gb4000 just so disapointed with mine at the moment
regards,anthony