Finally.......Pleasant sounding strings on a modest system

Hi, I'm new to posting here, I guess there's more free time these days. My ultimate test for a stereo system is how well solo piano and symphonic strings are reproduced. I figure if a system gets these right, everything else will sound good too. (to test bass, I throw on some Marcus Miller) For years, and with many different speakers/amps, I've been frustrated with the sound of the violin section of symphonic recordings, even when it seemed to be a good recording. I made some changes to my system in the last few months and I finally have enjoyable sounding symphonic strings and solo piano from my CD's. My only source these days is CD's, having sold off all my LP's in the 1990's and not up to speed yet on streaming. The first change I made was switching the power tubes in my Prima Luna Prologue from Gold Lion kt 88 to Tung-Sol 7581A . I always heard a hard, glassy edge in the treble with kt 88's even though I liked the muscular bass. This new tube reproduces the treble more smoothly, with good clarity and articulation and also has strong bass. The next change was lining a portion of my speaker cabinets with sonic barrier, the one with the copolymer layer, which tamed an annoying hot spot in the midrange. Then the final change was the addition of an R2R DAC which created a more smooth, organic sound to my ears. Now considering a dedicated cd transport. But so far, these 3 changes have made me a much happier listener.

My system:
Prima luna Prologue
Tannoy Revolution xt 8f
Denefrips Ares II DAC
Marantz CD 6006 as transport
non-exotic cables (Blue-Jeans)
Nice job of assessing the issues and tackling them in a very practical manner. Well done. 

Streaming is great. 
Definitely worth similar time  and effort to get a handle on it.
Good work. For strings, try fo.Q tape. Remove speaker gaskets (if any) and put thick fo.Q tape in place. Then cut pieces of fo.Q tape and stick them on the speaker basket (frame). 

fo.Q is a special piezoelectric vibration damping tape. Unlike most vibration dampers it does not suck out the life and dynamics. Instead it eliminates only the smallest micro-vibrations. The result is even more presence and detail is revealed. Instead of massed strings sounding like massed strings it sounds more like what it is, a lot of individual violins. Instead of one violin playing one note it sounds more like what it is, the multiple strings of cat gut being drug across the violin string creating a whole series of tones with just the right attack and bite to let you know its really a violin. 

Piano is tough because even just one note is three wires tuned just different enough to never be a pure tone, and in a frame so big the whole thing is made to resonate. Just looking at a piano you can see its the biggest instrument in the symphony, and sound being a physical phenomenon with the lowest most powerful sounds being physically longer wavelength its easy to see why the piano is such a challenge. Its this combination of detail with mega resonance that makes it so darn hard to reproduce. 

This tape won't add anything, but it removes so much crud you had no idea was there you won't believe the improvement. 

Does the tape leave any residue? Concerned about that for future sale of speakers
No residue! Its fantastic stuff. Pliable and stretchy, sticks with almost no pressure. Yet even after clamping for a long time it can be peeled away with no residue. There's a carbon fiber washer around the spindle of my turntable, the record clamp squeezes the record down onto that hard enough to bend the record down onto the platter. Its a fair amount of force, and clamped down like that a lot. But when I wanted to peel it off to replace it came right off.

Not that you would ever want to remove it. Only if you wanted to keep the tape when you sell the speakers. Which you probably could do. I've peeled some off, stuck it back on the non-stick backing paper it comes on, and then used it again later. Whatever adhesive they use is darn near magic. But two sheets is only about $40, expensive in the world of tape but a bargain in the world of audio tweaks. One inch on a tone arm and you will hear it. One sheet on your speakers and you will swear you have a new pair of speakers!

The only real drawbacks are it doesn't do much if anything to improve bass response, and it comes out of one small company in Japan and takes a couple weeks. But it removes so much detail smearing grunge you won't believe it.
I agree that orchestra string sections can be a real bee-otch when it comes to reproduction at home.  I admit to having a Prima Luna Prologue as well, and it's gotten me closer to anything I ever got from trannies.  My modestly priced NOLA Boxers also go a long way in providing convincing string tone. 

Then again, the original recording is absolutely crucial.  Oddly, I've largely gotten better string tone from my domestic Angel Records than I get from German or British HMVs.  I enjoy Philips orchestral recordings more than I should, as well.  Some of the Academy of St. Martin-in-the-Fields recordings are outstanding.  I love my London/Decca records, too.  DGG  recordings are more miss than hit but the performances are often too superlative to pass up.  Then there's Bruno Walter's Columbia Symphony Orchestra recordings.