Amps for B&W 805 Diamond: Rogue Audio or Krell, Pass labs, ML, Accuphase

@truongv0ky I ran B&W N803 with Pass XA250.5 and Audio Research LS-25 preamp. Great combo. The XA series would work well with the 805s.
I think the sound you’re looking for you’ll find with Pass XA-30.8. 
I had Rogue separates (ST-100 and RP-5) and while very good the Rogue stuff tends to lean slightly towards dry sound in my opinion. 
Also, your Chord Qutest will be a good match with Pass Labs gear.
The Qutest has great tone and it won’t be masked or veiled by the Pass amp.

Well, I’d rule out the Medusa for previously mentioned reasons, and I’d rule out McIntosh because the treble will likely be too reserved for your tastes.  I’m not familiar enough with Krell as they seem to have shifted back to their more classic sound, which is a good thing so worth exploring.  If looking at Pass I think the X150 would be the one to focus on as the XA series might be a little too soft in the treble for your tastes.  The one that intrigues me is the Plinius P10 that is considerably cheaper than the others but seems to exhibit sound characteristics that are close inline with what you’re looking for.  This review may be of interest to you…

https://www.whathifi.com/plinius/p10/review

Thats all I got for now, and I’d encourage you to read as many reviews as you can on these three amps to see if one seems better suited to what you’re looking for than the others. 

McIntosh pairs excellently with the B&W diamonds.  The newer Macs are not reserved or rolled off but smooth enough to give your speakers the ultimate in resolution with none of the excessive artificial brightness.  Heard this pairing many times and also Mac with even brighter speakers like Klipsch Heritage and they sounded like a winner every time.  Mac and Harbeth? Not so much but with the diamonds the system shines.  

Thx @soix ​​​​@audphile1. I’m doing the research for those.

Thx @avanti1960, what model of McIntosh will be suitable for 805 Diamond?? I am also looking for the hybrid ones such as MA252 or the solid ones such as 6600, 6800, 6900, 7000, but do we need to stay away from the ones that are too old (more than 30 years old)

@truongv0ky 

Buy as new as possible- 10 years old max.  The hybrid amps (252, 352) sound excellent and do work well with the 805d.  I would avoid their entry level amplifier.