Quality of old Chinese Valves/Tubes is High!!?

[GlennSprigg]

I unashamedly love all of "Mr. Carlson's" videos. (No-one speaks clearer).
Anyway, in one of his old posts, be was repairing an old but well known Guitar Amplifier, and replaced a 1st stage Tube. (Intermittent internal short from the heater filament to the surrounding cathode).  He talked a bit about the extreme vibrations inside the amp, due to the large internal speakers, that literally shake the shit out of the valves/tubes.
He said though, that he would normally love to use tubes labelled as "Made in USA", but they are not as strong internally.  Although a lot of 'modern' stuff from China may be cheap & nasty, he says that back in the days of Tube production, their manufacture of such copies were much more internally robust, and were  built to last!! 

[jxjbsd]

Generally speaking, the quality of electronic tubes produced in China in the 1960s-1980s is very stable.These electronic tubes are not of very high quality, but there is no problem in normal use.

[GlennSprigg]

Thanks.  Yea, he said he would not argue about 'Audiophile' quality, as it's always
in the 'ears' of the beholder...   

[GlennSprigg]

Just to add to that??...
What IS it that certain 'Audiophiles' try to explain about Quality??  It's a physical mechanical device with plates and a vacuum. Is it about the actual mechanical design/shape etc of the plates/parts within??  I can't get my head around that... 

[jxjbsd]

 I belong to one of them 。
but，I can't fully understand the behavior of these people.
In my opinion, the main differences of electronic tubes are: 1 material, 2 electrode mechanical accuracy, 3 vacuum degree
High quality electronic tubes are usually produced by these companies: GEC，MULLARD   STC Mazda、Brimar  ，Telefunken Valvo   From Britain and Germany  ，and  PHILIPS .

[GlennSprigg]

Ok. However one aspect really confuses me. If physical design/shapes of plates etc is so important, what about the difference between directly & indirectly heated Cathodes??  Indirectly heated ones have a smooth geometric shape, but directly heated ones are just a spiraled heater element coil?  I would have thought the latter would be be more 'dirty' noise/quality wise?