Hi Bob,I have the Chenin and use a select pair of E.H. gold pin 6SN7s to very good results,I think the pair were $25.00.Listening to well recorded Jazz L.P.s through my overhauled vintage Quad electrostats,vocals along with acoustic instruments are truly shocking at times.Truth in timbre is what I hear and what I value highly.There are boat loads of vintage 6SN7s in the World,finding a silent operating vintage pair like the Tungsols,you will $PAY$.I had a pair of silent round plate Tungsols which I sold last year on Audiogon.It was pure fluke I ended up with such a quiet pair.Vintage R.C.A. 1940s are also a great 6SN7.Also if you can find a nice "quiet" pair of Sylvania metal base 6SN7A or 6SN7W metal and or the black base type.These are also a great! 6SN7 and a very handsome looking vacuum tube at that.Right now my Chenin is tubed up with a Bendix 6106 in the power supply...$20.00,I see the price has gone far beyond that now.The regulator's are apair of 6F6G Sylvania 1930s vintage clear glass,etched base with old round logo on bottle...$8.00 for the pair at a antique radio show.I bought many more 6F6gs new in the box for very little.With this combination of rectifier and regulators listening to Big Band,Hard Bop,Jazz and heavy Rock through my Dynaudio Special 25s,there is added weight,bite and slam from the lower midrange on down that is very well defined over the stock tubes.Horn sections are particularly good.Vocals and music heard through my Quads with these tubes installed are in the room with me I find more so then with stock tubes.The stock tubes are very good in the Chenin and shoulded be dismissed because most are Russian made. My phono section has a pair of Telefunken PCC88 at $40.00 apair new in the box and finally apair of R.C.A. 6C4 also an inexpensive vintage vacuum tube.I have on hand afew select line stage and phono grade tubes from Sylvania,Western Electric, Philips,Telefunken and Siemens that I have collected over the years that would have a dramatic effect in other brands of preamps and phono stages that will respond to $expensive$ vintage tubes other then SupraTek,the Chenin model in my experience anyway.