Sophia Electric tube quality

I had a faulty Royal Princess 300b tube and they replaced it promptly and were very polite, I was impressed. That tube had wonderful sound in my SET amplifier.

Elvick's suggested hot lick test would have no relevance as to a tubes performance, though could prove very useful in human IQ testing.

You're indicating you think Sophia's response was disrespectful or something. Buy tubes from Kevin Deal, then call him and say you were thumping on them and you think they're microphonic. His response will burn a tattoo on your ears with unchristian language that may question your parentage and other cognitive abilities. I'd buy from him anytime and I own a Sophia amp (my second).

Despite your recommendation of not to tap the tube, well constructed tubes do not ring when tapped. 

Emission labs 300b XLS come with instructions never to tap on a tube that is in use.