OT: Care and feeding of vacuum tube electronics?

My $0.02 worth, You'll have to give it a little time to "warm up" (won't work until it does). As far as "cool down", it won't, until you shut the power off. Vacuum tubes use a filament (similar to that in a light bulb) to heat them up so that they will operate (so DON'T block any of the ventilation holes, or you risk disaster). Two suggestions. 1: Check the back of the unit, and see if it has a tube listing, or check each tube for it's type (will usually be an alphanumeric, example: 12BE6). 2. See if you can locate a supply of replacement tubes. At last check (couple of years ago), Radio Shack would special order 'em, allow <mumble> weeks for delivery, so, I suggest checking Ham Radio swapmeets and flea markets. Optional: See if you can get your hands on a "Tube Tester". They used to be in drug stores everywhere, now they're kind of tough to find. Be advised that tubes tend to have (or did tend to have) a higher tendancy to fail, than solid state devices. I think I've got a tube substitution guide around here somewhere for RCA tubes.. Hope this helps... Will Mark Gregory wrote: