The linestage Paul Birkeland built for me is a version of the Soul Sister/Kugelis project that appeared in VALVE some years ago. Up front are IAG TVC volume controls, and it uses the 6C45Pi tubes your post was inquiring about, driving MQ cobalt B7's powered by dual shunt-regulated power supplies and EL84 current sources. There is plenty of power for driving just about any headphone loads and my Senn 600's sing sweetly. The coupling caps were upgraded to TF V-caps. Paul designed some pretty casework for the piece as well. Cheers, Hank in Eugene
Here are two pics, the linestage sitting on a separate phonostage both PB's work, and under the hood of the linestage.