Has the New Pre Amp' been supplied with a stock 6922?
Have you tried your still used Telefunken tubes in the New Pre Amp' ?
My experience with swapping out ECC88 and 6922, is that a Valve Brand and Period of Production can vary quite noticeably in their sonic when used on a particular device and the demonstrations I have been present at, has shown the findings of Tube Rolling will vary across devices. Hence I use Two Different Brands from early 60's production on a DAC and Phonostage.
Either of Interest or not, I recently learned a adaptor socket can be used to allow for a 6SN7 to be used as an alternative Tube.
When my system is once more fully assembled, I intend on trying this out as I have access to many versions of these tubes.