The big one on the right with the porcelain insulation on the business end is for a Series 1 machine. It’s a type of plug which was used quite widely on all manner of Continental domestic and commercial equipment until the early 1960’s or thereabouts.
The one in the middle is the more common of the two all-Bakelite plugs which mate with the later flat-blade male socket used on the Series 2 and Series 3 machines. As far as I know, it’s an obsolete connector which was used almost exclusively in Switzerland, usually for domestic and office machinery, audio amplifiers, slide projectors and suchlike.
The one on the left is simply a variant of the one in the middle, with added earth contacts.
Of the three, the big one is nowadays relatively easy to find The earthed one is definitely a rarity, although it’s the only one of the three which I know is still available on the Continent brand new – at a price.
So what are these things called, apart from a female plug? Well, I’ve asked a lot of people and searched a lot of websites and I still don’t know what the proper designation is of any of them, so if you’re an authority on obsolete European mains connectors, I’d love to hear from you. I can though say for sure that despite what you might read elsewhere on the internets, a Euro C9 female plug does not fit the later type flat-blade socket on the Series 2 and 3 machines. However hard you try.
Actually, I should perhaps qualify that by saying that a Euro C9 female plug as moulded onto the end of replacement mains cables sold for Revox tape recorders does not fit, and it does not fit because although the socket blades are the right distance apart, they are too thick and too wide.
Anybody want a spare mains lead for an old Revox?
One obvious way forward if you’re stuck for a mains lead for a Series 2 or 3 is to hard-wire it to the blades of the male socket on the machine then try to get some good-quality heat-shrink tubing over them. You probably won’t be able to get the machine back into its case and it won’t look pretty, but it’ll work, and you’ll be able to unsolder the wires and remove the excess solder if in due course you do acquire the kosher plug.
The other option seems to be fitting a different connector to the machine, and I have looked into this. The existing socket removes easily enough and all that’s needed for a replacement mounting plate for a new one is a nice piece of black 3mm acrylic, but the big question is what connector do you put in it?
The ultimate problem-solver would be the ubiquitous Euro C14 chassis plug, but there’s nothing like enough room to fit one without surgery to the motor housing. After that, it seems to me that almost every readily-available socket would either foul the screws with which you mount the new plate to the motor cover (assuming you use the two existing tapped holes), or it would be deep enough to risk contact with the fan on the motor shaft.
If you’re not bothered about keeping the machine in original condition though (or capable of being readily returned to its original condition), I guess you could take inspiration from some of the “modifications” which surface from time to time. Perhaps the wackiest one I’ve seen so far involved a conversion to foot control and a vintage Singer mains socket screwed to the back of the motor housing …