What a beautiful amp!
I had a '58 which was very similar in many ways, which went to a very good customer in WA. It can be seen here.
I suspect this vintage Maton Mastersound amp was made very soon afterwards, so am having an educated guess at 1959. The cabinet covering and grille are identical to the '58, but the chassis is now at the top of the cabinet, valves are all the smaller type, and the output transformer is now mounted on the chassis, not the frame of the Alnico Rola speaker. I can't actually identify the valves, as the codes have rubbed off all of them! However, it's plainly a valve-rectified single-ended amp of probably only a few watts or so.
Serial number is B4750. (the '58 was B4708)
But what tone! This thing is absolutely amazing, and its sound and rarity are going to cause me to keep this for a while. Another reason is that I am now paying for amps the sort of prices I was selling them for only a year or so back, and I'd need to ask a figure which I doubt I'll be offered. Clearly word has finally got out about just how good (and collectable) early Australian valve amplifiers are.
This vintage valve amp is dead original, down to the last screw. Truly GROUSE!
Sold to buyer in Sydney