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
Many here are not as students but as colleagues. I trust that you do not treat your colleagues as students, at least not with any success.

We have one thing in common: not proned to the upgrade virus, at least not for me in what I call the "Foundation System" (downstream of source).

Your sources and cables preclude confidence in your recommendations. Low resolution from the former leads to false perception regarding the latter.

Placing a big flat piece of glass between your speakers is a sure-fire way to kill imaging and soundstage, but perhaps your (now) unique and excellent speakers minimize that in your main system.

As long as you are happy, that’s what counts.

Dave
Geoff, sorry about the spelling mistake - English is not my native language.

Dave, you made a philosophical mistake that is taught in undergraduate class. That is all I said.
Beyond that, I knew you would play the heads I win, tails you loose game. Still, that does not mean you are right. I know I will never convince you because science and the scientific method are irrelevant in your phantasy world, but here is a proper test of the Chromecast Audio: http://archimago.blogspot.nl/2016/02/measurements-google-chromecast-audio_27.html
As it so happens, I also listen to real live (acoustical) music, and I must say that on the main system the recorded version (if recorded well) comes pretty close, apart from the inevitably more limited dynamic range compared to a live symphony orchestra or choir. But then, we don't live in concert halls or churches.
Not sure what you mean by the piece of glass, but go and listen to a live classical concert, and you will discover that there is not that much soundstage and imaging going on either when you close your eyes.
It is good that you listen to a lot of live music and especially that you enjoy your system. My point is only that you have little to no evident experience with any of the recent digital gear, nor cabling, so it is not helpful to post your opinions on those things. Looks like you could contribute quite a lot of good advice on the music threads...

As for turntables, I doubt that you will be effective at changing anyone's mind on that one way or the other, so why not give it a rest. 

The big flat piece of glass is the plasma TV you listed as part of your system.

Dave
OP, a good example of a turntable to consider would be Rega or VPI

but if the room is taken care of as per the post above, I’d rip the CDs onto a mac mini or purpose designed storage system and get a good DAC, while paying attention to galvanic isolation - Schiit makes one called Eitr and it can be returned if there is no improvement

you have the best or one of the best $500 CD players from a few years ago, but that does not mean it is the best possible way to get digital sound from a CD to your pre-amp

also be sure you have the best recording/mastering of any music you care about

you have a very good system already so improvements in SQ will not be inexpensive