Just a note - we've built a prototype Paramount using the 5670, and Ed is listening to them this week I think. It works exactly as outlined above, and incorporates the new dual C4S/shunt reg board (the one in the Eros). If it all works out there should eventually be a conversion for existing Paramounts to the new board, which will make it a little easier to use different tubes as drivers. Personally, I'm thinking of the 6SN7 - but them, I've always loved the classics!