new to tubes

i have never had any tube equipment and am thinking about trying it out. i am learning slowly about it and thinking about taking a leap with a lower priced piece. i currently have a Cambridge Audio 840v2 integrated amp and a pair of Fritz Grove monitors. my only source is a Squeezebox Touch. i already plan to get an Eastern Electric Dac. my only concern is how much power is enough to drive the groves as they are only 86db efficient. my room is only 13'x 11' treated,and i dont listen past 92 db. i'm thinking on the lines of a Jolida 502b to start. trying to stay under $1000 used. any thoughts?