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
Thanks so much everyone I really appreciate the time and thoughtfulness that went into these responses. I'm getting a ton of great information. 
As others have said, focus on speaker placement, listening position, and possibly placing equipment stand to one side of listening position as opposed to between speakers. Treat the room using acoustic panels behind speakers, at primary reflection points on sidewalls, and behind listening position. Use bass traps in corners. GIK and ATS Acoustics are two companies that can help with this. They offer much information/products online.

After addressing the above, then consider upgrading your components. I agree with those that consider your preamp/amp/speaker combination to be fine and feel they would support improvements on both your digital and analog sources. Once you have optimized your room/system placement start another thread regarding each source.That said, my thoughts are to consider using a separate DAC to support the CD player as a transport as well as the Bluesound Node. With vinyl, given that we are talking table/arm/cartridge/phonostage the upgrade path becomes more complicated, and can be more expensive. I think I would start with the cartridge, then look at the phonostage.

Good luck with whatever avenue you choose. 
As for speaker placement and room modes, the simplest way to procede is to use REW (room equalization wizard, a free software package, see here: https://www.roomeqwizard.com/) and a cheap calibrated microphone to measure in room response. I am sure you will be horrified. Next, move the speakers around and add some rugs etc, as per advice here, to see if you can improve the response. If you want to improve the response more, you will need to use a parametric equalizer, either in software or in hardware. See here for a software one: https://sourceforge.net/projects/equalizerapo/

Great advice on the digital equalization. Then you can just throw your turntable and LP collection away. lol

Dave