This is a complex question, which depends on many factors. The tubes we use are of very high quality and have been selected to be the optimum choice for our designs. There are many NOS (new old stock) tubes on the market that in some cases can change the tonal, noise and distortion characteristics of your microphone.
While you may be happy with the result, you may also be disappointed and find the tube that came with the microphone sounds better. To find out, you will need to experiment and that can be expensive but of course the choice is yours if you wish to experiment.
We choose our tube type carefully to allow us to have enough stock to manufacture in the quantites required to satisfy our customers whilst keeping the mic characteristics constant and to ensure support for the product for many years to come.