What's the best 6NS7 tube you have tried in your Atma-Sphere MP-3 preamp?

When I had an mp-3, I thought the best sounding 6SN7 variant was the

Shuguang Treasure CV181Z from Grant Fidelity

@marco1

No, the cv181z were always real stable. That being said, the tube pins and socket connections are sensitve - you just couldn't push a tube in and let it roll. Sometime it's needed a VERY MINOR tweek of the tube - adding a little twist, little bit of lean, or just a reseat is all it would bring it in  Don't discount the signal tubes either