PrimaLuna Evo 200 underwhelming


Hi all, I wonder if someone can help or advise. I bought an ex. Display Primaluna Evo 200 a couple of weeks ago, mainly based on all the rave reviews and excellent comments on various forums. I must say, that vocals are terrific but overall, the sound seems muffled. There seems to be a hole where the mid range detail should be. I have tried the 4 and 8 ohm settings and there doesn’t seem a great deal of difference. I am using it with a Linn Genki CD player and Robson Acoustics Opulus speakers, also Vintage Tannoy Mercury speakers. I haven’t messed with the tubes because I have no idea how to do that. I so want this amplifier to sound beautiful but there is something missing. Can anyone help please?
golfnut2
I must that things do sound a whole lot different through the Tannoy’s. Maybe keep the Evo 200 and sell the Robson speakers. Thanks for all your replies, much appreciated.
Thanks again all, sorry if I have not responded directly to any of your responses, I am new to this forum and not quite sure how it works, needless to say, I have appreciated all the responses and advice. To be honest, I think the Robson speakers are the problem, it sounds like the detail is in there somewhere but can’t get out, if that makes sense. There is so much more going on through the Tannoy’s, which are of course easier to drive. Somebody said it’s about synergy and think that is the key. I am in the UK, so find it difficult to get help from distributors here, even the one I bought it from.
@golfnut2  

the sound seems muffled. There seems to be a hole where the mid range detail should be.

I assumed you have tried your Robson speakers with other amps and they didn't have these negative characteristics?  If so, what amps have sounded good when paired with your Robsons?  Just trying to see if it's a topology synergy thing in play here.
I'm going to suggest maybe some bigger Tannoy speakers. Maybe with some Kimber PBJ or Timbre interconnects. It's not the amp, that amp can sound magical but not so great with small speakers. My little LS50s worked best with lots of solid state power. 
Thanks. I have tried Naim XS3, Rega Elicit-r, Roksan K3 and my own Naim Unity Atom. All drive the speaker well, except the Atom, which actually sounds nice but lacks power and mid range detail. I didn’t like the hard sterile, almost unrelenting sound of the others. The best I heard was a PL Prolougue pre-amp with a Cyrus power amp. The sound was amazing but out of my budget, hence I saw the Evo 200 and thought it might sound as good. It nearly does but the lack of mid detail is just so obvious. The Evo 200 has a 30 day return policy, so I have the option to return it, or try and sell the Robson’s and start again.