What's the weak link in my system?


     I've pieced together the best budget system I could afford over the years but I'm just not thrilled with the sound I'm getting. Can anyone help me identify the weakest link (s) in my system so I can upgrade? I only have the budget to upgrade one piece at this time. I'm most interested in listening to vinyl.
Currently Configured:

Pro-ject Genie 1.3 Turntable w/ Sumiko Pearl Cartridge
Bellari VP 130 Phono Pre w/ Tung-Sol Tube & Replaced Power Supply  
Marantz CD 6006 CD Player
Parasound P3 Stereo Preamp
Parasound A23 Power Amp
PSB T6 Platinum Speakers
Bluesound Node
AKG K702 Headphones
Audioquest Daimondback Interconnects
Audioquest Rocket 33 Speaker Wire

Also Have:
NAD C235BEE Integrated AMP
Monitor Silver RS6 Speakers
Marantz SA8260 SACD Player (Used to sound great but doesn't work consistently - not sure if worth having repaired)
Musical Fidelity V Can Headphone Amp


So.... I think I have put together the best possible system configuration using what I have. What would be the weakest link / first to upgrade? Turntable? Phono Pre? Pre-Amp? Suggestions of products to upgrade to without breaking the bank? I've accumulated a bunch of stuff but I'm really a novice so any and all feedback would be greatly appreciated!   

jdm11
Thank you loomisjohnson - I've been reading up on DACs - so many brands and reviews and opinions out there though it's a lot to sort through.
 
Thank you cd318  - that was an interesting read particularly in relation to recommended proper speaker placement on for the PSBs. I can make some adjustments there. 
Thank you willemj. As I said I'm a novice and don't want to throw good money after bad so I appreciate the information you've imparted. 
jdm11,

Be careful not to swallow every pill crammed in your face. Your preamp/amp/speaker combo looks pretty solid. In that case, sources are your best bang for SQ improvement, excepting the one thing I do no see discussed:

Have you experimented with speaker placement? Are your speakers spaced a good way from the rear wall? What are the dimensions of your room and what types of acoustical treatment have you installed?

Dave
+1 for Dave ...

The room should come first. Get it dialed in. A good place to start is with a ten-pack of SR's HFT's and install as directed. 

Frank
Thank you Dave. I don't; my disposition is naturally diplomatic. Listening room is 18 x 22 with hardwood flooring and one door. I haven't installed any acoustical treatment so the walls and ceiling are sheetrock. I also have experimented some with speaker placement but the link posted by cd318 above is an article suggesting specific spacing / placement for the PSBs which I'll try. Good to hear the feedback on the preamp / amp speaker from you and loomisjohnson and by inference from inna as well as the vote of confidence in the Marantz from willemj. That helps narrow it down to take a harder look at turntable, phono pre, speaker placement and acoustical treatments. Any suggestions?