What's the rest of your system, especially speakers?
Bidkidz, you actually aren't satisfied with your Pass X250? I know how highly you've praised it in the past. I own VT-100 Mk II with B&W 802 Matrix III. It is a great combination with plenty of power for me. The bass will not be what the X250 gives you, but it is very good for tubes. I wouldn't recommend the VK60. It will not be enough power for your 803's.
I 2nd the no vk 60 recommendation. And I'm a big bat fan. With yoiu being used to a big solid state amp, and those b&w's, not likely a good match. If you can you with 2 vk60's in mono...I bet that will work great. If you want better bass extension and control, a VK75se will give it to you in spades. You might be able to get by with a single 75se...it matches all the characteristics your asking for....I've owned both.