Amps to consider for Nautilus 802s

I am running a Jeff Rowland Concentra integrated amp, a pair of B&W Nautilus 802s, a Music Hall turntable, and a Meridian CD player. When i play CDs there is plenty of power and fidelity. However, most vinyl still sounds weak and the amp needs to be cranked up to get any decent volume. (The same problem happens if i play music from an ipod or macbook).

I am guessing that my solution is to purchase a stereo amplifier. The concentra does have a port to add an amp. Does anyone have a range of brands they recommend? Rowland offers various amplifier options but they exceed my budget at this time.

Thank you,
David