Do NOS Mullard EL34 tubes last much longer than NOS SED (Svetlana) EL34 ?

I have four SED "winged C" EL34's that came with my purchase of a Dynaco ST70. I doubt that original made-in-Britain Mullards will last any longer. Don't forget that the so-called NOS Mullards are actually present-day production from Russia.

forget life, either should last a long long time.

which sounds best to you? do you want to listen to the less preferred sound for a long long long time?

You could buy from a source that lets you return them, try the least expensive compared to your existing.

sound great, keep em. if not as good as your existing, return, get .......

forget life, either should last a long long time.

which sounds best to you? do you want to listen to the less preferred sound for a long long long time?

You could buy from a source that lets you return them, try the least expensive compared to your existing.

sound great, keep em. if not as good as your existing, return, get .......

This is the right advice. And don't buy tubes from anyone that won't let you return them for any reason within the first thirty days.

 I doubt that original made-in-Britain Mullards will last any longer. Don't forget that the so-called NOS Mullards are actually present-day production from Russia.

I find that true NOS tubes often test far stronger than their reissued counterparts. Certainly not a rule of thumb by any means, but I see it on a daily basis. As an example, just this morning I was courtesy testing a client's brand new, never before opened, straight from the factory Russian made Genalex Gold Lion KT88s to ensure they were properly matched and they each tested at 57- 58 on my TV-7 tester, where 44 is the threshold for good.

By way of comparison, I have a number of different quads of NOS GEC and NOS Genalex/GEC KT88s with production dates spanning across multiple decades and they consistently test in the mid-to-high 70s, with one quad in the mid 80s. I don't see that at all with the reissues...don't see them reaching much past the mid-60s even.

It can be a much different story when you get into the smaller tubes (e.g. 12AX7), where in my experience the Chinese tubes often test freakishly high. 

NOS Mullard tubes are relatively easy to identify / authenticate. A simple google search will give you a reasonably well informed primer.

@inna 

Good to hear from you!