30 year old player, worth an upgrade?


Nothing wrong with my 30 year old Marantz CD40 player but is feeling an itch to upgrade.
My current amp is the Bada Purer 3.8Mk hybrid bought new 5 months ago.
Will any of these players provide a definite improvement in sound quality?
1) Nad C568
2) Bada HD23
3) Marantz CD6006 (used)
I do not have a chance to home audition any of these so would appreciate any inputs you may have.
The first two retails at about the same price while the third is about 40% lower.
Thanks!
ertorque
Get a pro grade CD player like a Tascam from Musicians Friend and run a digital line to the DAC of your choice.  There are some very good DACs on the used market that offer excellent value.
I think you should try to find a good vintage cd player prior to 2000 like an adcom gcd 750 or a wadia or an accuphase they will all sound better in many ways than what you are looking at right now.
I'm still using a 1986 Denon 1500 and still sounds great!  I have friends with newer CD players, only one can match the sound, most can't compare.  I attribute this to 1500's Brown and Burr DACs !! 
I’m still using a 1986 Denon 1500 and still sounds great! I have friends with newer CD players, only one can match the sound, most can’t compare. I attribute this to 1500’s Brown and Burr DACs !!
@dgb553
I am sure the Denon must be very good. I learnt something new about this player when I googled for this Denon 1500: https://forums.stevehoffman.tv/threads/a-legendary-classic-the-denon-dcd-1500.214154/

Looking at the pictures of its internal circuitries and parts , I don’t think the Marantz CD40 is as good, components wise.