The part of the vacuum tube which "lights up" is called the heater. For US tubes (which you have here) you can tell the voltage of the heater based on the tube's number. Standard US tube numbering has numbers, letter(s) and numbers (and maybe letters). The leading numbers indicate the heater voltage in .
How to Photograph Glowing Vacuum Tubes. Bandmaster Reverb Chassis. 1972 Fender silverface AA1069 Bandmaster Reverb Chassis taken with a 30 second exposure at f/7 and ISO 100 with a Sony A350 with a Sigma 24mm lens. I allowed about 3 seconds of direct light from a distant fluorescent light to fall on the chassis during the exposure to make the tube glass and chassis detail visible.
We have some tips and tricks to help determine if you have a bad vacuum tube when you do not have access to a tube tester. Browse: Home / How To Tell If Your Tube Is Bad. One of the power tubes has a strange stain in the top of the glass and some rust in the inside bottom. The tubes glowing is only an indicator of heater function. So it.
A small cosmetic note. Everything turns on and looks retro-style. The glowing tubes. The yellowish VU-meters. Well, the bright BLUE LED (power) is totally disturbing. I ended up opening the bottom plate and snipping and cutting one of the LED wires.. Now it is uber-cool. It would be nice if the full review.