The Cure on SS-30
Here's LibreCandombe (from Uraguay?) running though a selection of hits by The Cure on a nice looking SS-30. A good range of sounds and styles on show here.
Solina with MIDI?
I don't think The Cure ever used an SS-30 themselves . It seems they were an Eminent Solina band. Interestingly it's claimed in this auction that this one - their actual machine - was MIDI retrofitted.
The pictures are preserved by MatrixSynth and you can see they went with an XLR connector.
It's beena while since I looked around for such things but seems both a few people offer solutions for the Solina. There's lot's a of ribbon cable being used, which is an intriguing idea.
DoepferThe Dopefer solution is based around their MTC64 MIDI TO CONTACT / GATE .
It's actually a design one of their customer's has documented and provided for everyone's use.
The interface is based on CNY74-4 opto-couplers. This would work just as well for the SS-30.
The Kenton solution is a bit obscure and there's no clues on the website on how it works.
This one is discontimued