I was distracted by other projects, which is so often the way with me so I haven't tried them yet.

I'll be happy to point people this way. I haven't found time to look at the CV side yet but have just ordered a couple of cheap H11F1's to have a play with them. I eagerly await the MK2 schematics. Thank you for sharing your work.

@Baron von Pooppenstein I put the circuit together and it works great, thank you. I'm amazed these things aren't better known as they're so simple yet can do so much. Would you object to me sharing your schematic (full credit to you & Olegtron of course)? I feel sure that even though it means you can make your own, it will develop more interest in the brand & their products. I tried the CV mod but it generates a drone that is present regardless of whether you have patched anything or not so I need to go back over my work and find out where I've gone wrong.

Thank you so much for sharing this. I'm considering buying the MK2 but wanted to play with the original on a breadboard first.

Is there any chance you could share a larger version of your schematic as I'm struggling to see it?