Elrog 300B vs Takatsuki 300B tubes

I'm not a technical person and don't claim to be. Everything I've read up to this point has stated the Elrog is a direct replacement for the 300b as they matched the filament current and voltage requirements. I accepted this as fact and had no logical reason to doubt it. If there are certain amplifiers(for what ever reason) that can't use the Elrog this should be made known(thanks Dmarkov). I suspect they may be a minority. Based on a goggle search I did to read other Elrog user's experiences, it seems the vast majority have had positive outcomes.

At this point with this relatively new tube, more information will be gathered and some level of compatibility will be known over time. I would never expect that everyone will always prefer the Elrog over other worthy 300b competitors. There are simply too many different ears and amplifiers/systems for that to be the case.
Charles,

The Elrog has a different internal impedance, gain and filament type to a conventional 300B. Internal impedance (resistance) is approx 900R vs 700R, gain is higher than a standard 300B and the filament is thoriated tungsten type vs oxide type. It will give less power than a standard 300B under the same conditions.
Elrog recommends to use the tube into higher impedance output transformer loads than a conventional 300B because of the higher internal impedance.
It can have a problem in an amplifier that was designed around 300B specs as it did in the case I mentioned. Problem = mismatch and sound compromise.
Voicing/sound of the tube is different from "standard" 300B but this could be either good or bad, users can decide for themselves.
In absence of proof that it works in a particular amp, like with Franks as we have here, or when one has no possibility to just get a bunch of tubes and hear them in his own amp, it could be wise to contact the amp designer for advise. More experiences similar to the one with Franks will tell the story eventually.

The longer I've live with and listen to the Elrog ER 300b the more I recognize how wonderful this tube is. The past few weeks I've been able to listen to quite a bit of music and it has been a truly enjoyable time. The sole purpose of Elrog it seems is superior emotive provocation. They simply connect me thoroughly and deeply into the musical soul. I've sat at home and played CDs all the way through and then replay them. I listen to songs three times in a row, it's that pleasurable. These tubes offer such a natural, fully developed and realistic tone/overtones that I'm just completely pulled into the listening experience. They really do everything in an excellent manner across the musical board.

I was at such an exalted level of contentment with my EML and Takatsuki, I'm actually surprised the Elrogs have taken my music listening to a higher plane( to this degree). As these tubes accumulate playing hours they just continue to improve. This is so satisfying because straight from the box they sound exceptional. I truly hope that the Elrogs will work in the vast majority of 300b amps as well as they do in my amplifier. This has been a sublime experience for me.

Interesting read regarding the Elrog ER 300b.
Where does one order a pair?
How much is a pair?
I recall reading a while ago they were on back order (but I forget from where) is that still the case?
Thanks for any assistance.

Lak,
They're 1099.00 USD pair. I bought mine at tubesusa.com. Demand seems greater than the current supply at this time.
Charles,