My 6 month evaluation of the Cabernet is that I love it. Took me a while to sort things out but now my old preamp sounds downright harsh. I have found that tube selection makes a huge difference. I’ve also found that when I change tubes in the Cabernet I have to change tubes downstream too.
For example, the TS round plate 12sn7 sounds amazing as long as I use a tall 7n7 input tube in my amp (Inspire KT88 Firebottle) and use 6v6 outputs. If I just pop some 807 tubes into the amp it doesn’t sound very good until I change the input tube. If I use Raytheon 6f8g tubes in the Cabernet I can’t get sound I really like unless I put in e3375 tubes in the output. 12sx7 tubes in the Cabernet I really like an RCA 6sn7 in the input tube of the amp and 6ar6 tubes in the output. And on and on. Once I dial in the system it sounds amazing but every change requires changes elsewhere to get sound I like.
The switch that allows me to use both 6v and 12v tubes cost an extra $500. That gave me pause but I think it was worth it in the end. I have been able to get several pairs of TS round plate 12sn7 at reasonable prices. That probably evened out the price right there. On top of that I was able to get the so-called “bad boy” Sylvania tubes with little trouble. I can also use tubes that aren’t available as 6sn7 like the 12sx7 and the 14n7. The latter have extra support rods as compared tp the 7n7 and 6sn7. If you already have a good collection of 6sn7 tubes maybe the 12v switch won’t make sense for you but if you are starting out I recommend it.

