You really just have to do your homework with vintage valves or NOS.
You need to know what labels, plates, and getter constructions look like, and be able to look up valid date codes.
The vacuum tube industry was just as incestuous and precarious as the record pressing industry. Many brand name tubes were assembled at other tube companies factories and the tooling changed hands as well. There’s a lot to know.
Often, someone like Andy at VTS is one who could tell you what’s what. Fore mentioned Kevin from Upscale and Brent Jessee are all good resources, but you pay for what you get. Many other folks are just talking out of their arses. Parroting what someone else has said on the internets. Crazy.
If high quality signal tubes last 5-10k hours, it’s not much of an argument that they are a value even at several hundred dollars apiece if you find the right tubes, in the right condition, for the right circuit! But now, or cry later.
You need to know what labels, plates, and getter constructions look like, and be able to look up valid date codes.
The vacuum tube industry was just as incestuous and precarious as the record pressing industry. Many brand name tubes were assembled at other tube companies factories and the tooling changed hands as well. There’s a lot to know.
Often, someone like Andy at VTS is one who could tell you what’s what. Fore mentioned Kevin from Upscale and Brent Jessee are all good resources, but you pay for what you get. Many other folks are just talking out of their arses. Parroting what someone else has said on the internets. Crazy.
If high quality signal tubes last 5-10k hours, it’s not much of an argument that they are a value even at several hundred dollars apiece if you find the right tubes, in the right condition, for the right circuit! But now, or cry later.