Burning question

Is my digital playback up to modern standards?
I currently have a Mark Levinson 31.5 and 30.6 digital playback system that has served me well for over 15 years. Two years ago I had it gone through with new power supply caps, diodes, rectifiers etc. that brought it up to new and maybe a little better. I am wondering how it fares against modern designs, and if I should replace it to get most out of my system. I exclusively listen to red book CS's. My replacement budget is 20K new or used. I would appreciate your feedback and suggestions for replacement if deemed necessary. The closest dealer to me is 100 plus miles away making in home auditions impractical.
My system:
Wilson MAXX 3
Pass SP30
Pass XA160.8
Transparent Reference MM2 cables.
Appreciate your input,
Ag insider logo xs@2xsigmund

I think Teajay offers some astute comments. Specifically, of the two components you have, I would also opine that the DAC is the weak link, as there has been significantly more improvement in DACs over the last 10 years or so. (Admittedly, though, it has been a couple years since I heard the ML combo). By contrast, in my experience, a number of the best transports today are still those that were exceptional back in the day, e.g., Esoteric P-0, Jadis JD-1, CEC TL-0, etc. As another example, I used to own an Altis Centauri transport a number of years ago that I would love to get back. Again, based on my experience, these units, especially with some minor mods, can stand up to most of what is available today (with the caveat that I have not heard the truly expensive state of the art stuff, such as the Metronome Kallista Signature or Esoteric P-01, which I believe are out of your proposed price range)

Indeed, as you can tell through some simple searches on the topic, other than the Esoteric VRDS transport mechanism, there has not been much improvement in (and perhaps even a decline in) the quality of transport mechanisms currently available.

With that said, I do not have any opinion on the Concert Fidelity DAC to which Teajay refers. However, there are a number of DACS under 10-15k that I think will really give you a notable improvement. Of those, my favorite is the Stahl Tek Vekian Opus, but the MBL 1611 and Esoteric D-02 are also good choices. Based on my recollection, I would also suggest the EMM Labs DACs as far superior to the ML 30.6

If you were to go the single box route, the Playback Designs MPS-05, Esoteric K-01, and EMM Labs XDS-1 are all excellent choices, depending upon your particular tastes. I have also heard a number of comments about the Soulution 540 as well, but have never heard it in person.

Best of luck.
Thanks Rzado,
Those are basically all the units that I have been considering. Any ideas as to where the PS Audio Direct Stream fits in this mix?
I feel the transports built in the '90's were better built than what's manufactured today. I have a Spectral SDR-3000SL and its arguably one of the best transports ever built. Paired with my MSB Analog dac, it produces magic with redbook discs. 

I would love to compare the Spectral to the Levinson 31.5. That was another transport I was looking at the time I purchased my Spectral a year ago. The 31.5 is a beast of a unit. They certainly don't make them like they used to!