I have an early version Mr Nixie DIGNA Valve Hybrid MM/MC Phonostage that has undergone modification that enables the 6922/ECC88/E88CC Tubes to be used.
Even more recently I have been introduced to the use of Low Eddy RCA connections used on both Chassis and Cables. This is another adaption not carrying too much expense to achieve, that is very much worthwhile considering if one feels there is more desired to be extracted from signal path of a electrical device.
In a system I am very familiar with and one that has been used when I have been a participant in offering ears as part of development works for Audio products being produced. As part of R&D, I have been A/B compared a SS Phonostage and Interconnect Cables with original supplied RCA's and as the design with the RCA connectors swapped to Low Eddy models. The impression left on myself after experiencing the Low Eddy RCA's mounted onto the Chassis and Terminating the Cables, is that this is something I intend on adopting within my own system where it is possible to achieve. The veil/smearing that is removed, alone as a perceived improvement is quite something. The additional perceivable benefits where the shaping and envelope of the notes and vocal that manifested is totally wanted to be experienced again.
Any device out of Warranty could easily undergo such an alteration.