Amp match for B&W 685s

Current System:
Cambridge Azur 640C CD player
B&W 685's
B&W stands weighted with lead shot
Speaker wires (unsure of make....got from audiophile store). They are 3 cables weaved.
Onkyo TX-SR 507
Speakers are bi-wired.

I'm in the market for an integrated amp to improve the system. I'd like to go with tubes or hybrid. From what I've read, I'm thinking Jolida or Cayin. Any opinions? What sort of power do I need for the B&Ws? They're rated at 88db. I'm hoping to buy something used for under $1000. Could go up to $1500. Listen to variety of music. Looking for warmth and depth.

Thanks.