Supratek Tubes and Tube Swappin' for Everybody

Have been a very satisfied owner of a Chenin preamp - acquired (used) in 2014. Primarily playing vinyl (60s-70s rock plus some jazz, classical).Tube lineup consists of: Gold Lion KT-66 Electro-Harmonix 6SN7Sovtek/Electro-Harmonix 6922Mullard 6688Mullardd GZ37

I know this thread hasn't been super active recently but thought I'd drop my experiments in here. I got my Cabernet about a month ago. Mine has a twist though. I had Mick put in a switch so that I could use wither 6sn7 or 12sn7 tubes. I have accumulated a large number of 12sn7 tubes over the years and now I'll finally be able to try them out!bes. 

I started out with the 12sx7 tubes Mick sent with the preamp, think they are labeled GE. It was a good baseline to start with but their limitations were obvious when I started to listen to other tubes. 

The next ones were some odd tubes. The 14n7 is a 12sn7 with a Loktal base. All you need is some adapters and they will work in the octal sockets. It's my understanding that just about all 7n7 (the 6v version) tubes were made by sylvania and are exactly the same as the equivalent 6sn7. The 14n7 tubes are interesting because they have the additional support rods like the super expensive 6sn7wgt metal base tubes. None of the Sylvania 12sn7 tubes had those supports as far as I can tell. In addition to that, these particular 14n7 tubes have grey glass. To my knowledge Sylvania never made a grey glass 6sn7 let alone 12sn7. I might believe that these were some of the suer rare NU round plate tubes except they are actually labeled Sylvania... Anyway, I had to hear them. In comparison to the 12sx7, the grey glass 14n7 tubes were smoother and more lush. The bass is warmer and looser, the whole presentation became more "tubey" I suppose. 

Next up was the Sylvania "Bad boys." These are the bottom getter, three hole tall 12sn7. Gotta say, these are really good. I had a NIB sleeve of these I bought 15 years ago or so. Everything tightened up and became more vivid. I get why people have been praising these. 

I am currently listening to the Tungsol round plate 12sn7. They are living up to the hype. Very well balanced, spacious, sweet, controlled. Man, why do these have to cost so much? The 6sn7 versions are quickly becoming extinct. The 12v version are merely very expensive as opposed to exorbitantly expensive.  I am going to continuing scouring tube sellers to see if I can get another set. 

Coming up I will try a variety of RCA, Sylvania, and more 14n7 tubes. I also have a large number of 6sn7 and 7n7 tubes, mostly Sylvania. I do have a pair of Ken Rad round plate 6f8g tubes I'm curious about. Just waiting for the adapters to arrive...

This is really cool. Pray tell, what "baseline" Supratek model did you have him start with, upon which to apply this customization?

Does it have a phono stage? LCR or "standard"?

Markus