Ive been using three pairs of vintage amperex tubes interchangably which are the same type and manufactured within the space of 5 years. In my preamp. Each pair sounds significantly different. How can any serious audiophile move his system ahead when such variances are introduced just by changing tubes even when they are from the same manufacturer and era?
Listeners who want to hear whats there should seek out the best solid state and improve their front end to get what they want. Tubes are a excercise in listening to different types of harmonic distortion and frequency variations.
For example , you could take a dozen average solid state amps and preamps, listen to some Beatle recordings and you would know exactly what each Beatles voice sounds like.
You could then listen to high end tube gear, and never quite be sure what anyone sounds like since you would hear a slightly different vocal timbre with each piece of gear and which each change of tube.
No wonder pro's rely on solid state!