I think the presence of a grey panel, pill voltage selector, plastic-shaft mains switch, along with what appear to be Parmeko transformers probably means your chassis was manufactured in the fall of 1964 (definitely pre-1967).
Is there a serial number plate on the top back panel of the cabinet?
Vox ac30 serial dating
I don't have it here with me but I'll check as soon as I can, I tried to get some codes from the more visible pots but couldn't get anything relevant, is there one in particular I should check?
I think the transformers they are all Parmeko and it didn't come with a serial plate, the serial is stamped on the chassis thought (AC30/6 BASS 8225).
I think Jack is right and this is a modified super twin...
I'm going to check if the cab is drilled for the side handles and if the vents openings look like they were cut at the factory!
If you can see a two letter date code stamped on any of the potentiometers (just below the value of the pot), the first letter represents the month (beginning with "A" for January) and the second the year ("H" for 1960, "I" for 1961, etc.).
If the second letter is "L," your pots were made in 1964.Grey panel means post July 64 ish, Parmeko transformers used a lot at the end of 1964 and then not at all and finally the Mk IV plastic mains toggle switch introduced in the Autumn/Fall 1964.So the chassis is as jackinthevox says end of 64, the cabinet is a different kettle of fish though.Mustard Mullard caps have a Letter/Number/Letter date code.The first letter is the quarter of the year ("A" = January thru March) and the number is last digit of the year ("4" = 1964).Since your cabinet has a single handle at the top with no sign of holes for an additional two handles and there's evidence of two holes on the side of the cabinet (possibly for a trolley), I wonder if your cabinet was a speaker cabinet for a later Super Twin that was adapted to accommodate a 1964 chassis.