tube amp for b&w signature 805

In general, B&W speakers require high current solid state amps to really make them sing. I would do with a SS amp and tube preamp or CDP.

Look into a plinius 8200, although this is a solid state integrated, it has a "tubey" sound. While I had the N805s, I deffinately felt that the Plinius was the best especially when wanting a more tubelike sound out of the speakers. Also, I would suggest a used Musical Fidelity Nu Vista M3, this is a hybrid integrated which is superb, but might be overkill for the speakers, although the 805s are great, they just might not be refined enough for the MF amp. Good luck

The opinion of Bigkidz regarding B&W and SS is a common one. However, I had success with several tube amps with even more expensive B&W designs like Silver Signature, Signature 30, and even Nautilus 802 and 801. What you need is a powerfull tube amp with good speed and bass control. I've had good results with Aronov LS-9100 monos (I just sold my pair, but there is another one on gon right now , upgraded version, priced quite low). Also, Air Tight ATM-2 is a great for B&Ws, they pop up sometimes at under $3000. Audio research VT-100 MkII might work too, In fact, I am using one right now with my Sig 30. Might be selling it soon to go for CAT JL-2.
Just avoid single ended low powered amps, they don't have enough juice for B&W. If you go for solid state, there is only few which would satisfy you as a tube lover. The best for your speakers would be any Symphonic Line design. RG-1, RG-4, RG-7, if you can find it.

Good luck

Good luck

The Airtight ATM-2 should sound awesome with the B&W.