I agree with the above statements, but would add one note: If you do buy a tube tester- get one that checks the tube at full operational voltage. Some anomalies(IE: anode to grid breakdown voltage) won't show themselves at reduced voltage levels and/or if the tube is not at full operational temperature. Some testers also have small speakers that allow you to actually hear any microphonics(noise) that the tube is producing. An important feature if you are screening tubes for use in phono stage or pre-amp operation.
popping sound with new 6922 tube
I am new in the tube world. I just replaced Siemens 6922 tube with Phillips. When I turn the preamp up for the first time in the morning, I get a popping sound (probably from tube) after a couple of seconds. A noise is delivered to speakers, too. Is it ok? Will it disappear as the tubes age? Or should I get a different pair? Thanks for your help.