Best significant upgrade? Dac? Preamp?


Hi guys!

Im hoping some of you with knowledge of my system can help me make a good decision about my next upgrade.
I would like a surprising and obvious difference not hard to spot subtle change.
From my research i think the next move should be the Dac.
I would like to explore DSD,i have some SACDs now.
my system:
Mark Levinson 320s preamp
(Would i see a difference with a ML no.52?) I am also looking at the no.52 ,would i see a big difference compared to the 320s? Worth the extra $$ ?
interconnects: Acoustic Research master series silver high definition RG6
ML 431 amp
XLR: +bo ? +ba ? Only info on them

Wilson Audio Watt Puppy 5.1 speakers (serie 7 tweeters) +transparent music wave plus cables
Arcam rdac (wifi) with Teddy Pardo power supply.
Running on mac air (usb) ,Tidal HIFI
(i currently listen most of the time to this vs rarely SACD).
Thanks!



128x128nicsaudio
Concerning DACs inhave seen good reviews on Lampi and Chord but they are really expensive !
I'm Cleary biased since I now sell PS audio gear, but the new torreys operating system that is in beta right now takes the DS dac to another new even higher level.  The direct stream Jr is lower cost and uses the same OS.    
I also agree power conditioning makes a huge difference.    I'll make a post about the new one from audioquest I just got in. 
 The previous incarnation of the PS audio top-of-the-line DAC doesn't do DSD, but it is an amazing performer. And it is in your price range. I recommend looking at the perfect wave DAC Mark two, wIth bridge Mark two if you can find it. If not you can always  upgrade the bridge directly through PS audio.   Best of all, with this type of investment which is already greatly depreciated, you can sell it for nearly what you paid for it if you decide to move on. The other option for you in the future is to upgrade this unit for the newer DSD model by replacing the internals which are available  from PS audio. 
I would say room treatment. 50% of the sound is room acoustics. GIK polyfusors are very effective at absorbing some bass and also diffusing mids and highs. 4 of those in a room can do wonders.