I always wanted to have a 6SN7 preamp. My last attempt was converting my 56 Pre to 6J5 Transformer couple line stage. It is being rebuild atm because of the hum issue. One of my buddy recently build an simple 6SN7 2 stage preamp. It is from the VTV valley issue 11. It sounded very nice but a bit forward. In this project I will be modify the power supply section adding a choke and 1 more stage RC filter. I happen to have some old stock of Holco and Caddock resistors that match the value require. It is a one gain stage with a Cathode follower design. Just finish drilling and sanding the chassis. Just put on first coat of primer.