Cary slp-05 tubes rumor or fact?

Has2be has a point BUT I'm betting you will know if the tubes are better or not even with the extra connection.
Tyi them with the sockets. If it indeed sounds better, you could consider something more drastic as Has2be suggests also.
If they don't sound better, don't even think about if it's JUST because of the sockets (it won't be), sell the tubes and move on.

I'm curious as to why you are so anxious to try new production 6SN7's given that the 6SN7 is one of the few tubes for which there are still tons and tons of excellent new-old-stock available at reasonable prices. The better production out of Shuguang is indeed good stuff - I'm not trying to diss the Black Treasure tubes - but it hardly seems necessary.

What type of sound are you looking for John?

I have tried quite a few different 6SN7 tubes in my SLP-05 (but admittedly not the Black Treasures). While changing the tone and character of the music the different tubes almost without fail saw a loss in dynamics and air and sometimes resolution too.

I spent considerable time and dollars experimenting with NOS 6SN7's in my Cary SLP05 preamp. I found that the Pope 6SN7GT,s were far and above the best sounding tubes in this preamp.

Psvane 6sn7 will fit.I'm using them in my Cary 05.They sound much better than the stock tubes.