Must be my week. My friend just gave my a Sencore Vacume Tube Tester that he picked up from a Thrift Store for $2.50, and it works like a champ. I know what you are thinking,(Vacume Tubes? Do they make them any more?). YES, All the high-end amplifiers STILL use vacume tubes and I build/repair amplifiers as a hobby/side-line and NO, I do not wear a pocket protector and thick glasses(I had Laser eye surgery 3 years ago).
Ask any guitar player.
There is no Tone like Glow in the Dark Tone.