Again with apologies to those who are bothered by this tangent, I think we are actually saying much the same thing, Mr. Khomenko. I have or had mentioned in this thread and/or others that:
(i) operating voltage helps determine tube life, i.e., the more voltage a tube sees, the hotter it runs, and the quicker it will normally die; and
(ii) in order to avoid the sudden, deleterious application of voltage to tubes upon start up, some tube equipment - including your products, I am now learning - features a "soft-start" function that brings up power gradually.
Since we're on the topic and your Rex preamp features tube rectification, I should mention that tube rectification functions like a variac to bring up power gradually.
Not to belabor the point, but based upon the evidence I have seen, GENERALLY speaking, if the small-signal tubes in a given circuit are run at reasonable voltages (i.e., well below their maximum rating and they thus run cool) and the piece uses solid-state rectification without a soft-start or standby feature, which is the case, in my experience, with most tube preamps, 24/7 operation yields better tube life (and better sound). I again quote from the owner's manual of my VAC Renaissance tube amp:
"How long should tubes last? It has long been known in professional circles (and probably now forgotten) that a tube such as the 12AX7 will display BETTER performance characteristics after TWO YEARS of CONTINUAL operation than when it was new. In normal use it is not unusual for a low level [small-signal] tube to last 5 years or longer. Output tubes [i.e., power tubes used in tube power amps] are another story, as they are continuously providing significant amounts of current." (Emphasis original).
Incidentally, if, because of work demands, I know that I'm not going to be listening to my system during a period of a month or more (a common scenario for me at year-end), I will indeed t
(i) operating voltage helps determine tube life, i.e., the more voltage a tube sees, the hotter it runs, and the quicker it will normally die; and
(ii) in order to avoid the sudden, deleterious application of voltage to tubes upon start up, some tube equipment - including your products, I am now learning - features a "soft-start" function that brings up power gradually.
Since we're on the topic and your Rex preamp features tube rectification, I should mention that tube rectification functions like a variac to bring up power gradually.
Not to belabor the point, but based upon the evidence I have seen, GENERALLY speaking, if the small-signal tubes in a given circuit are run at reasonable voltages (i.e., well below their maximum rating and they thus run cool) and the piece uses solid-state rectification without a soft-start or standby feature, which is the case, in my experience, with most tube preamps, 24/7 operation yields better tube life (and better sound). I again quote from the owner's manual of my VAC Renaissance tube amp:
"How long should tubes last? It has long been known in professional circles (and probably now forgotten) that a tube such as the 12AX7 will display BETTER performance characteristics after TWO YEARS of CONTINUAL operation than when it was new. In normal use it is not unusual for a low level [small-signal] tube to last 5 years or longer. Output tubes [i.e., power tubes used in tube power amps] are another story, as they are continuously providing significant amounts of current." (Emphasis original).
Incidentally, if, because of work demands, I know that I'm not going to be listening to my system during a period of a month or more (a common scenario for me at year-end), I will indeed t