Slipknot1
With my Chenin, the tube rolling has been pretty limited. I tried swapping out the stock 6922's with Amperex NOS only to be disappointed with the results. I was very pleased however, with replacing the stock 6SN7's with NOS RCA Grey Glass 6SN7. Overall, I have to agree with Slowhand. I think Mick knows what he is doing in his choice of tubes when he ships a preamp. Who am I to argue?
I too enjoy my Chenin with the RCA VT-231 Grey glass. The Raytheons VT-231 was also superb in my application. In fact, I now have 3 pairs of Raytheons in my stash so as not to missed the ride if you know what I mean. As for the phono, as I posted a long long time ago and repeatedly, the 6C4 is the money tube for me. If you have not tried it already, I recommend the Tungsol 6C4 and the Raytheon 6C4. The Tungsol have warmer mids (like the RCA's which I know you are using), a very balance top and solid bottom. The Raytheons have a better top end but less "warmer" on the mids and it also has a little more "kick" on the bass than the Tungsols. After trying these tubes, I can now say, that the Mullard M8080(which I thought the best tubes for me in this position) was inferior to both.
Lisbon,
List your tubes on the Chardonnay if you have not change them already. Also, what about replacing the input cables from preamp to amp? Have you tried having the pre and the amp plug into a common outlet(local ground)? Just a thought!
greetings