sfcd 1 best tubes

just purchased a used sfcd1 and am interested in changeing stock sovtek 6922 and recomendation i like a tube sound quiet background not that important thanx
Sonus...I've owned the SFCD-1 for several years and have tried many different tubes in it. My two favorites are as follows. A pair of Siemens E188CC / 7308's do a good job of delivering more detail and tighter, well defined bass. They do a pretty decent job of delivering the 'tube sound' you are looking for. My favorite is the Amperex JAN 7308 Orange. They take all of the fine attributes of the Siemens tubes to the next level. I would have to say that Amperex tubes made a 20 - 25% overall improvement over the stock Sovteks. These tubes are somewhat hard to find though and I have heard that this tube is commonly 'faked'. Good luck in your search. I hope you enjoy the SFCD-1 as much as I do.
While I have not had a SFCD, I do own an SFP-1 signature. I have used the Siemens (70s vintage) gold pin and they have been the best I've tried--clear well defined and very open soundstage. I have not had the opportunity to use the Amperex, but given Jaguar's comments--I'd like to.
I've had a lot of listening hours in front of a buddy's SFCD-1 and tried more than a few tubes from my personal stash, but he was using some mid '60s US Amperex white label 6922 PQs to good effect. I sold a pair of my later production Siemens 7308s to another buddy and he's quite happy with these, although the presentation might be a bit more extended at the extremes vs. the more midrange pronounced Amperex tubes.