I see any tube as a gamble to a certain extent. Much like all the rest, just somewhat higher risk I would say.
If you must drop a lot of $$$s on tubes, buy only from reputable sources with a rep for good customer service. Or else go cheaper when possible and risks not so great.
In recent years I’ve only bought tubes from two sources: 1) Audio Research or 2) Guitar Center to play with cheaper options where practical. Sometimes it is practical, sometimes not. For example, tubes used in a phono section probably need to meet higher tolerance standards than those in the line stage. In my Audio Research sp16, 1 of three phono section tubes must meet higher tolerance. Only pricey tube from ARC will do for no audible background noise. All others (5), not nearly so much. If you buy all six, that one costs more and is marked for use in the proper place.
I do not do tube power amps to-date so no recent experience there.
If you must drop a lot of $$$s on tubes, buy only from reputable sources with a rep for good customer service. Or else go cheaper when possible and risks not so great.
In recent years I’ve only bought tubes from two sources: 1) Audio Research or 2) Guitar Center to play with cheaper options where practical. Sometimes it is practical, sometimes not. For example, tubes used in a phono section probably need to meet higher tolerance standards than those in the line stage. In my Audio Research sp16, 1 of three phono section tubes must meet higher tolerance. Only pricey tube from ARC will do for no audible background noise. All others (5), not nearly so much. If you buy all six, that one costs more and is marked for use in the proper place.
I do not do tube power amps to-date so no recent experience there.