I would stick with what you know well works in your system for a preamp. I happen to be a big fan of the 6SN7 based preamps but don't know the TAD sound. In sum don't fix what ain't broke.
So looking at your other ideas-
The Dynavector cartridge is very detailed and I think sounds great.
Cables too many variables but the signal cable ICs I own are not in use . You can do lot better but I have no idea what you hope to acheive.
The EH6CA7 is one of the biggest sounding of the EL 34s if you put aside the KT77s for a minute. I like JJ E34ls but they don't synergize with my monoblock tube amps which came stock with the EH 6CA7, not EH EL34. I hope in you mean 6CA7 specifically as well.
The only thing I was thinking of changing to was the GL reissue KT-77s. The JJ KT-77 sound great but one blowing after 10 minutes scared me off. The buzz on them has been notoriously unreliable.
The GLs supposedly sound even better but they haven't been out long enough to comment on reliability. They also cost far too much for current production. They cost $20 more a piece than the GL KT-88s, themseles high priced already. I use the GL KT-88s in a different system. I must say they use they are fantastic tubes. I guess given the cost of NOS the nearly $50/tube I paid is OK.
So looking at your other ideas-
The Dynavector cartridge is very detailed and I think sounds great.
Cables too many variables but the signal cable ICs I own are not in use . You can do lot better but I have no idea what you hope to acheive.
The EH6CA7 is one of the biggest sounding of the EL 34s if you put aside the KT77s for a minute. I like JJ E34ls but they don't synergize with my monoblock tube amps which came stock with the EH 6CA7, not EH EL34. I hope in you mean 6CA7 specifically as well.
The only thing I was thinking of changing to was the GL reissue KT-77s. The JJ KT-77 sound great but one blowing after 10 minutes scared me off. The buzz on them has been notoriously unreliable.
The GLs supposedly sound even better but they haven't been out long enough to comment on reliability. They also cost far too much for current production. They cost $20 more a piece than the GL KT-88s, themseles high priced already. I use the GL KT-88s in a different system. I must say they use they are fantastic tubes. I guess given the cost of NOS the nearly $50/tube I paid is OK.