6SN7 Tube Voltages


I’m not a tube expert but have a new (newly built) preamp that takes 6SN7 tubes. Basic research finds that newer versions of this tube have a higher voltage rating than early versions. Meaning that if the preamp voltage supply exceeds the tube rating the tube might not last long. The tubes in question are these, from newer to older:

6SN7GTA/GTB - 450 volt maximum and 5.0 watts per section
6SN7GT/WGT/WGTA - 300 volt maximum and 3.5 watts per section
5692/6SN7 - 275 volt maximum and 1.75 watts per section.

I asked the preamp manufacturer if the tube supply voltage would cause problems with any of the above tubes. They responded that all should work except the 5692 because "the plate dissipation is too low". They did not state the actual tube supply voltage.

Does this answer my question? I only see references to voltages online, not dissipation.

Of course my fear is that I might buy a lower rated NOS tube set for big money, only to find it’s not compatible with the preamp.

Can one of the tube experts here please weigh in on this? Thanks.

jaybe

@jaybe No-one makes a 6SN7 (no suffix) these days so if you’re buying new tubes its no worries. If you buy NOS make sure you specify the suffix and you’ll be fine. 

@atmasphere Thanks. I should have specified NOS/used, but all the above tubes are that anyway.

I do have some new 6SN7 by Linlai, Psvane, Shuguang, and Cryotone. It's the older ones I'm asking about. Still not sure I understand the answers.

@jaybe 'NOS' stands for New Old Stock so I was referring to older tubes. If you're buying from a reputable tube dealer they will pay attention to the suffix of the tube type you specify. 

@atmasphere Got it.

My point is did the preamp maker correctly answer my question about voltages, which he answered with a plate dissipation comment. How do I know what the tube supply voltage is if the builder isn’t saying. His answer does not give me the confidence to go out and spend $500 on old tubes that might not work in my preamp.