Pardon me for seeming " unrefined " with thi statement, but I find it steps from absurd to accept a designer "voices " and amplifier aroud the sound of a cheap Chinese tube. Now, I am not saying that a circuit may be " adjusted " to accomodate a particular character of measured specs, but I find the reason why designers, any deigners use these tubes is not because the mplifier is voiced around them, it's because they are inexpensive and plentiful, and considering even a master like Kevin in terms of building a quality amplifier, which he does not need to prove by any means, might employ 12-18 tubes in any or most of his designs. It just makes economical sense to utilize an inexpensive, but reliable tube or the cost of the amplifier would be driven up by perhaps 20%. I am an owner of the last version of the well reviewed VAC Avatart SUPER and I have found changing out the front line 12AX7 an 12AU7 did more for this amplifier than power tubes did, however, I personally found the cyo'ed Svetlana KT88 winged C to provide the most uniform and transparent sound, but again, this could all be due to my up and downstream components. i have found no one solution fits all, there is no standard IMHO.
thanks for listening man, enjoy the music........
thanks for listening man, enjoy the music........