I bought this amp at an estate sale. The owner was a professional harmonica player in the 50's and 60's. He said this was the greatest harmonica amp ever made. Nothing on the internet to date or name it. I found a guy who used to work at the factory in Elizabeth. He estimated 1959. I want to sell it but have no idea of the value. It was reconditioned in the 90's and never played again. This thing is a cherry. Can anyone help?