6SN7 tube question

Thanks everyone. I'm a bit frustrated as I've had to replace the tubes just about once a year even though I listen on the weekends only, and my understanding is that the 6SN7 is one of the most reliable tubes and should last longer than that.
Sounds like I should give Andy a call.

Thank you, Al and Ralph. I was actually looking at the Sylvania tubes, but this particular era looks a little bit out of my budget. Circa 1970s is very reasonably priced, on the other hand, and I'd think probably better than any new stuff on the market.

Cdrc,

I always contact Mark and Nick at Rogue first if I have any questions regarding their product. I did so in this case as well. Rogue always offers one of the best customer service experiences in the industry. Nick informed me they no longer us the EH 6SN7 tubes because they found them to be too unreliable, and use Tung-Sol now. I wouldn't expect them to say much more since they probably use new stock tubes for new products to offer the best value to the consumer. I bought a set of 6SN7s from Rogue a few years ago that looked like NOS, but they also lasted about a year with moderate use so I thought why not try something different this time. Perhaps Lewm's suggestion is worth looking into as well.

Thank you all for your responses; I've learned something, as always on here.

John Tracy,

How do you check the filament voltage?

Thank you all for your responses. I don't even own an multimeter, but as Al advised I'd leave the job to someone who knows what they are doing. Sounds dangerous for an amateur...