I encountered the same problem with the Van Tec Speed controler. I called and spoke to the owner and he told me thats the way they are. He wouldn't do any thing for me except charge me a 20% restocking fee. They don't say anything about making noise in their ads. I guess you learned the hard way like I did and I hope it helps others to avoid this pitfall. I use Astro Flite Model 208D speed controls and they are great. Excellent low speed control and no noise what so ever. You can watch the prop turn on my large tug at slow speed. They can handle 30 Amps. and you can go to 24 Volts if you want. Many of my boat club members are also using them. Some of the guys use the proboat controlers on 6 Volts and get good low speed control but not on 12 Volts. I hope this helps Captain Bill