[SteveG]

Here's me 650 MX, that I've had for about 30 years.  Found it in the local paper back then for $50 and restored it, as the finish was too far gone to save.  That is the original speaker cloth! Lucky for me, as reproductions back then, weren't readily available. Seems to be a fairly uncommon model. Love that trap door dial on the 650 series!
[Image: http://www.surfacezero.com/g503/data/500...0_MX_a.JPG]
[Image: http://www.surfacezero.com/g503/data/500...650_MX.JPG]