Simaudio W7 amp sounds not quite expected


I currently have the Simaudio Moon W3 and like the sound a lot.  So I thought getting the W7 would be an upgrade but having bought online it's a bit of taking a chance.
Last night having heard the amp in my system for the first time, the sound is not quite what I expected.  Reading some of the review, I thought it would be a bit forward, neutral.  But what I heard was the complete opposite.  It's somewhat recess and a bit warm.  There is not enough mid range present (like the W3) and the sound is somewhat withdraw and lacking involvement.  The vocal is a bit recess than I would like.  For me the first thing any component needs to do is to effectively communicate the music, but the W7 at least in my system does not do that.  I have to say I am a bit disappointed. 

May be it's my preamp.  I am using single ended.  Anyway, I am getting a Pass Labs XP-10 soon so maybe hopefully it will work with the W7 better than my current preamp which is a Conrad Johnson 17LS.
andy2
@ andy2,

have read time and again that you need to let Sim equipment run for two to three days to warm up from their cold, then they start adjusting. So if you turn them off for a few days, then they still need two or three days to warm up and settle down...
try that before you do other things...
My point was that They apparently take that much time to warm up and settle down after being turned off for sometime.
so even if it's a used unit, and you turn it off then when you turn it back on you'd need to give it two or three days to warm up...
I feel stupid because the problem is traced back to a faulty speaker connectors - for whatever reason it slightly short.  Now the sound is a lot more like it.  It's like the W3 but a lot better in every way.
But anyway, will wait for the Pass Labs XP10 to see how it will turn out.