This is not “a” Williamson Amplifier, this is “THE” Williamson Amplifier. The British made original whose circuit design became the de facto standard for push-pull HiFi amps. Complete with power supply unit and umbilical cord. A few resistors and capacitors appear to be changed out, but largely these units are original and in remarkable shape for their age. They came from the estate of a local old school TV repairman. There simply are none available to compare. I can’t even find a picture of a complete unit like the one I have here. This should be in a museum or serious collection. I have not plugged these in, and I will not. This is something that needs to be carefully restored by an expert. I have no reason to believe that the amp doesn’t work, as it was found hooked up to a speaker. I will listen to serious offers, but would also just appreciate advice on how to determine a value for this. The amp can also be inspected in person in Baton Rouge, Louisiana, USA. Thanks for looking, I can take more detailed pictures as needed. The item “The Williamson Amplifier, Vintage Original British Made KT66 Tube Amp” is in sale since Sunday, April 29, 2018. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Amplifiers & Tube Amps”. The seller is “epador” and is located in Baton Rouge, Louisiana. This item can be shipped to United States.