I've had some bad luck with the JJ 2A3 - 40 tubes in my Stereomour. One tube went bad within 6 months. The replacement lasted 2 weeks and the 3rd lasted about one year before it started getting noisy. With the hum pot I could only get it to about 10 mV.
So, I started looking for a replacement that would offer similar sonic benefits to the JJs. I still like very much how that tube sounds. The tubes I considered included Shuguang 2A3 c-t, Psvane t2, Sophia Princess and NOS RCA dual black plates. They are all very pricey.
I finally decided on the EML solid plate. Feedback on the internet is very good and they come with an extended warranty (18 months).
They arrived today safely packed. The size is about the same as the JJs. The EMLs are beautifully built and have some heft. The hum balance adjusted to about 0.6 - 0.7 mV. This is the quietest of any 2A3 I have tried so far (though my experience is only with the Sovteks and the JJs). How does it sound? My first impression without any burn in is very favorable. They sound clean and rich at the same time.
So, hopefully I'll have more luck with the EMLs.