Hi Art,
Now you've got me interested! I have always wanted to know about the Mk II and what it sounded like relative to the Mk I. Since I have a Mk I, your experience might differ somewhat, but I love the Telefunken 6922's in the V6 and V7 position, Telefunken 12AX7 in the V8 and V9 position and a Telefunken 6DJ8 in V10. If you don't use phono and your unit has a phono section, you can economize with the tubes in V1-V5. Otherwise, use the same tubes in V1-V5. If the cost of this tube substitution is too expensive, you can either leave or acquire the stock EI Yugo 12AX7's. They are not bad at all. But do replace the stock Sovtek 6922's. With Telefunken, you will get deeper bass, better dynamics, and better extension in the high frequencies. As far as the Mark I is concerned, I have tried many tubes in the CAT Ultimate, particularly in the V6 and V7 position, and I doubt that you will find better than the Telefunken 6922. With other NOS tubes that I have tried, you are bound to lose something
Now you've got me interested! I have always wanted to know about the Mk II and what it sounded like relative to the Mk I. Since I have a Mk I, your experience might differ somewhat, but I love the Telefunken 6922's in the V6 and V7 position, Telefunken 12AX7 in the V8 and V9 position and a Telefunken 6DJ8 in V10. If you don't use phono and your unit has a phono section, you can economize with the tubes in V1-V5. Otherwise, use the same tubes in V1-V5. If the cost of this tube substitution is too expensive, you can either leave or acquire the stock EI Yugo 12AX7's. They are not bad at all. But do replace the stock Sovtek 6922's. With Telefunken, you will get deeper bass, better dynamics, and better extension in the high frequencies. As far as the Mark I is concerned, I have tried many tubes in the CAT Ultimate, particularly in the V6 and V7 position, and I doubt that you will find better than the Telefunken 6922. With other NOS tubes that I have tried, you are bound to lose something