Thanks @jonny - I have the Endorphin.es Terminal - the original one with the vactrols - such a smart design, they have a set of instructions for swapping the vactrols out and encourage rolling your own - I like it a lot!!
p.s. @2disbetter I am not a big fan of Make Noise modules. some of them are good sure, don’t want to put them down this is just my preference, but I always struggle with them a bit, exceptions are Maths, Erbe Verb and Mysteron - all excellent in fact those three together make an excellent voice! I also have the new Wogglebug, it’s great, but I probably wouldn’t be too upset if it went even though I do use it a lot. I would probably be equally happy with other random sources - I am more than happy with the results from patching stuff up in the ER-301 for example. I really disliked the DPO and the Echophon even though in theory I should have liked them a lot.
edit:sorry, I forgot to say another really excellent vactrol sound can be found in Mutable Instruments Streams - similar idea, take the response of the typical vactrol, emulate it and provide control over its behaviour - I like it a lot!