So i just picked up a 200dx dual voltage tig welder complete with water cooler from Duncan at Everlast Canada. So far machine is working great besides this odd sound that seems to be coming from the power source. So I get welding in dc and a few minutes into welding at moderate amperage 120-150 the machine begins to make a high pitch beep sound that gets louder and quiter as I throttle the foot pedal. The machine's performance stays the same when the noise is present but doesn't seem right. I contacted Duncan to let him know the issue and said he had never heard of something like this. He said since I was local to bring the machine in for an exchange no problem. Load up the machine and head up to Duncan's place. I get there we hook up the machine,weld with it for 15 plus minutes, different amperages and NO NOISE! Exactly what I thought was goin to happen. Duncan suggested maybe it was the torch so off I went with a new torch back home with my original machine. Hook it back up and new torch doesn't make a difference, the noise is still there. We both are stumped. The welder is setup in a semi-detached brand new house with 40amp service(40 amp breaker, direct wire into the panel).I also have a Miller diversion 165 that works perfectly fine with same power. Any help/feedback is greatly appreciated as I would like to get to the bottom of this. Thanks

I have a video of the machine making the noise but I'm not sure how to post it.