A matched set of tubes are usually used for push-pull audio stages. Someone has comparred transconductance to get similar readings.
Others may disagree but here is something that is close. Use two new tubes from the same manufacturer with same date code. They are usually more closely matched than mixed brands.
Norm
:Hi! I want to know what is a matched pair tubes and how I can match some tubes (maybe with a multimeter or tube tester)...
:Thank you!