Quote Originally Posted by WeirdBits View Post
Maybe a U Bolt of some sort as protection? If you can get one tall enough to still allow removal of the tube when needed.
Yeah, I reckon that's the ticket, thanks WeirdBits. Will have a look online and see what I can find.

Quote Originally Posted by Simon Barden View Post
Acrylic windows look nice but don't really add anything, and certainly not ventilation. A lot of that sort of pedal use lower voltages for the valve and use a red LED to obtain the valve 'glow' for show.
I think looking nice is an ok justification. People like to see tubes, so even if it's not utilitarian it still adds something. In the end it will probably come down to how much time I have spare, and what design I come up with for the enclosure. Given Lawry's choice of Purgatory for the name I was thinking of maybe ripping some Durer engravings to print on the box, and a window will probably be inconvenient to navigate around.