300B SET or EL34 SET

i honest think it’s more of the designer; how it was built and not the tubes itself.   Comparing apples to apples; 300b will for sure sound better in triode compare to el34 but if you are looking for power and low efficiency speakers than el34 would be a better chose.   Both are great tubes; it has it’s own strengths  and weakness.  

I agree with many comments here but I will say after running 300b's for a few years and having to retubing my amp I wish I gone el84 lol.  

I have very good transformers in my amp hashimoto's and do not feel I'm missing anything( over other tube verities) in the bottom end or top end, I have efficient speakers though 94db and 99db.

 I ran the 300b's on those 94db speakers for a couple years made great music but they were limited to lower listening levels so IMO your 89db speaker wont be a great match, doable but not satisfying IMO. 

also 300b's are getting very pricy compared to el34's I spent $800 this summer on 2 new gold lions, and another $700 on small signal tubes (2x12ax's and 2x6sn's). keep that in mind every couple years buying 300b's gets expensive fast, specially if your pushing them with low efficiency speaker they will go faster. 

@glennewdick  The 300B tube was designed for extremely low maintenance and a very long life.  As an example, WE300B are spec'd for 35-40K hours, therefore, making their cost of ownership quite inexpensive when you amortize the initial cost over its expected lifespan.  I know many individuals who have ran the same 300B for years, and the tubes still sound and test like new. 

Hmm... After reading your posts maybe I'll should give up the thoughts of a SET amp for the Tannoys and be happy with my EL34 push-pull and my EL84 push-pull.
But I really want that EL34 SET and I really like my 89dB Tannoys. It took me long time to find a speaker that I was satisfied with. Sigh!

@verdantaudio
Thank you very much for the enlightning post. I've been wondering what I need all these "extra" watts for. Now I know:)

Another thing hit me. What about impedance throughout the whole frequency span? Does a speakers sensitivity tell the whole story?
I mean my ATC SCM 19v2 at 85dB is OK with 35w, but the impedance never falls under 6dB.
Problem is; I don't know how flat my Tannoys impedance is. I got some measurements, but I don't know how to read them.