The intention was to have a driver tube optimised for driving the 845 and to enable a two stage 845 amp which only uses direct heated tubes.
One of the customers who commissioned a set of these with all silver transformers ordered a life time supply of the tubes along with it.
Of course I am also making amps with other tubes this is the first one with an especially developed new tube type and it was triggered by another customer who was interested in having something unique like this.
I am not intending to stop producing Elrog tubes any time soon. And I will produce quite a few ER887 to have stock for customers with these amps for years to come even in case I need to wind down tube production for some reason.
It is a similar situation for another product of mine, the EC8020 phono stage. The EC8020 is probably one of the rarest tubes on the planet and I believe I am the only one offering a product with this tube. Here I also keep stock of tubes for each such phono stage sold.
Best regards