I have a valve (tube) headphone amplifier, and I've found that it usually takes about an hour for it to sound it's best. I'd like to design a 'clock' in a similar style that i can set when i get home to tell me how long until i can start listening properly. I've bought some nixie tubes for the display, but it's so long since I did electronics A level that I can't seem to remember anything useful! I want a two digit display, which will count down one minute at a time. The countdown time will be set by a rotary encoder. All I'm really looking for is a schematic for a similar circuit that I can use as a building block to get started. Does anyone have anything similar I could base it on?
