It depends what your application is. Some circuits require a 6922/E88CC, or even a 7308/E188CC, whereas others can accept a 6DJ8/ECC88. After that the fun starts.
That being said which Telefunken are you referring to, and in what circuit? Preamp, CD or amp?
That being said which Telefunken are you referring to, and in what circuit? Preamp, CD or amp?