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 will have anther go at swapping the input tubes, they solid though. Apparently the was ex display and never used, it certainly looked untouched out of the box. Just answer an earlier question, the Robsons sounded great through a PL Prologue Pre amp with Cyrus X Power amp. In hind sight, maybe I should have gone for that combo and it may have been a whole different story."

golfnut2, Ask Upscale to replace the input and output tubes, both. See what they say. Who knows what this demo was before you got it, could have been a return from someone else who did not like the sound. EL34s can sound great with the right efficiency speakers.  Maybe not so much with lower efficiency veiled over speakers. And, you may not be an EL34 type of listener and closer to liking the sound of KT88+ output tube sound as many have already suggested. If they don't want to help you on tubes, just return it. I bet the right small signal/input tubes paired with good KT88 output tubes would be more to your liking.   Best of luck.   
I have an Primaluna EVO 100 intgrated with Bluesound node 2i, innuos mini Mk III. The sound is breathtaking on my 8"   5 cu ft DYI 3 way towers. All with the stock tubes.  Not sure what to say other than you have a mismatch somewhere. My speakers are rated for 70w RMS. The bass is solid, low, slams. Highs are velvet voices and dynamic. I listen to Rock, Jazz, movie sound tracks, country, Christian, oldies from 60s, 60s, 70s, 80s. Bad recordings are noticeable.  Good ones , oh my gosh. 
I saw a post here stating that the 7581 tube was a direct sub for the el34. I don't believe that is correct. The 7581 replaces a 6L6/KT66, etc. 
What does a red LED to the right indicate?(Their manual download from PL/HQ only has up to page 10)