Recommendations for 5k upgrade


As winter approaches more time is spent listening so I have allocated this budget for system changes and/or improvement. Planned changes are marked between brackets.

Source:
PC based music server / SB Touch (ext. power supply upgrade, maybe Bolder?) fed into Eastern Electric MiniMax DAC with Dexa opamps. Alternative source: Sony DVP 9000ES CD/SACD via optical.

Amplification:
Conrad Johnson CT-5 with 6H30DR tubes, CJ LP140 mono blocks (tube rolling planned, which 6922?)

Speaker/sub:
Dunlavy SC-IV modded, Velodyne DD-12 or REL R305 (haven't decided which one to keep)

Power Conditioning:
Audience AdeptResponse 12 with e PowerChord (AU24e PC planned, dedicated 20A lines planned with the next room renovation)

Cabling:
IC: NordOst Valkyrja throughout (maybe Valhalla, looking for alternatives with better price/performance), NordOst Silver Shadow for S/PDIF
SC: NordOst Heimdall (probably the weakest link here, upgrade to Tyr2 ? Alternatives?)
PC: NordOst Vishnu to preamp and power amps, stock PCs on other devices (waiting for the final direction for PCs, not sure to stick to the loom theory, having all PCs of the same brand)

Isolation: mostly Black Diamond Racing cones/pucks and one BDR shelf under the preamp, some Stillpoints (planning to experiment with alternatives like Aurio, Symposium, etc, under the devices, maybe some for under the speakers)

Room treatment: just acoustic panels behind the speakers, need high WAF suggestions for my 21' x 30' room which has a half sloping cathedral ceiling and an open staircase. (looking for bass traps that can blend in with the interior for the corners)

I am not unhappy with the current setup but like to have more details without being too lean/bright.

What is my weakest link?

Of course YMMV but appreciate any suggestion to take this system to the next level without a second mortgage (or divorce) and/or improve the synergy between components. TIA!
polyglot
I suspect, given the quality of your gear, that the DAC and transport are the weakest links. You can get a used PSAudio MKII Perfect Wave DAC and Perfect Wave transport within your budget price. It's a very musical set up and was just reviewed in The Absolute Sound. I run mine through a CT5 and the sound is smooth but full of detail. Wish my speakers were compatible with those 140's!
Your system good as it is. The weakest component, for me, would be your sources. I have the same Sony you have. Its OK as a back up or to just try SACD but your other components are in another league. As far as your PC setup goes, I can't comment because the sound varies so much from system to system, I could only guess as to how good it sounds. My recommendation. Get a real CD player. That will be a huge improvement. If you need other formats besides Redbook, two players I would look at are the Ayre 5 series universal and the Cary 306 CD/SACD players. They both sound incredible. The reason I choose these 2 are for Redbook. With most multi-format players, CD quality is sacrificed. Not so with these two. They can easily hold their own against Redbook only players in the same price range. And since most people have a lot more CD's than other formats, it just makes sense to have a really good CD player. (CD needs all the help it can get).

I see that you are considering things like tube rolling and new cables. I won't tell you not to do that. Its your choice. I just don't think they will come anywhere near the improvements that a new source will bring.
I think you have a very nice, well thought out system and it's because of that I find your quest for more "detail" puzzling. Based upon my experience and what I've read of your components none of them would be described as highly detailed in their musical presentation. IMO trying to change a system's presentation with cabling is fundamentally wrong. It's also a poor value solution. I'm not saying that it can't work, but even if it does it will impede any further improvements in the future.

Before making any changes I would recommend you experiment with speaker placement and acoustic treatments. I believe that in a large room getting the bass right (which probably will sound a little light weight, at least initially) is essential to maximizing resolution and detail higher up the frequency spectrum.
I don't think that cabling is your primary priority. I mention the PC's because they DO make a BIG difference and can be upgraded relatively inexpensively. Improvements are not subtle.
Onhwy61, sorry if my quest misled you. In general, I wanted to take this already great sounding system to the next level -which is what I put on the last lines- w/o breaking the piggy bank. E.g. when I had, IMO, a good system a while back with the CJ PV12, MF2500 and Snell B Minors, I thought this ensemble is darn good...till I upgraded the components.

Placing speakers is a very well discussed and known fact (believe me I did that first) and acoustic treatment, or my specific limitation, has been mentioned already in my OP.