Tube guy gets a B&K: tubes vs solid state

You folks probably already know all this, but maybe these observations will be helpful for some newbie... (tubey newbie?).

I've been looking to understand how to improve the sound of my tube system and decided to try a SS amp as a point of reference, and potentially as a permanent switch. Thanks to many here, the desirable choice seemed to be a McCormack DNA. But being unsure I decided to take a cheaper approach and bought a B&K ST-140 ($202 on ebay + $27 shipping), version 2, toroidal transformer. It is like new. After swapping back and forth with my Marantz 8B I have the following observations. Rest of system is stock CJ PV-5, ProAc One SCs, ordinary car audio speaker cable (next upgrade), all Kimber PBJ interconnects.

The issues I have with my system are a desire for tighter bass, more openness, less of a congested presentation. I got my system in 95 or so, and did some comparisons to SS then, but sometimes you have to relearn old lessons.

1) I am amazed at how pretty and smooth a sound the B&K has. It is a "lighter" sound, more even and polite or reserved, and the various instruments don't seem to be congesting together. For a $200, 20 year old amp, it is quite amazing.

2) The sound of tubes is different from the sound of solid state. It's difficult to overstate the significance of this. The tube sound is palpable and dimensional. I knew this before, and these have to be the most commonly used terms but it's true. But it's a bit stunning to hear it again.

3) I would never be happy with solid state because no matter how pretty, it does not have this tangible substance, palbability, or dimensionality. It is key to enjoyment of the sound. It is sonic sculpture versus sonic painting.

4) I expected the bass to be deeper, larger, and tighter with the B&K. At first blush I thought it was. But after several comparisons, it is none of these. It is stronger and...tighter doesn't seem like the right word but it is as tight with the 8B. More importantly it is more real, because of the palpability, and that makes it sound more accurate or defined. On recordings with fuzzy bass, though, I think the even, clear, laid-back presentation of the B&K renders the bass with more seeming definition whereas the 8B seems to be trying to make it full and tangible but having nothing to work with, it just puts forth a kinda warm and soft bassiness.

5) I now believe the comment I read here, that a SS amp with a tube preamp will not give the dimensionality and palpability of tubes. One needs a tube amp for this.

I no longer feel I need tighter bass; I see it differently and very much like the bass I have with the 8B. I do think I could use more openness, a bit better high end (PV-5s, I'm told here, have rolled-off highs), and a less congested sound when the band gets busy, which somehow seems to be linked to the palpability or substance of the sound. It's like the thick palpability is a bit too thick and things get congested together.

I'm not sure whether changes to the amp or preamp will solve those, but the experience with the B&K suggests the next move is the preamp. I'm trying to decide whether to pick up something less romantic/lush like an ARC or VTL, or to send my PV-5 off for upgrades, or buy a newer CJ. At this point not knowing which will be the more effective it's a coin toss unless a killer deal comes along. I'm getting more reluctant though to alter the nature of my PV-5. Since getting back into hifi I have never seen one for sale.

Any suggestions or thoughts on my next move would be most welcome.

Jim