LINN: Power amp for Isobariks?

I use an LK280+spark and an LK275 to power my Isobariks (bi-amped), but I find the sound a little bit 'dry' and harsh at the top end. I'd like something with more 'boogey' factor and rythm. I'm thinking of selling these and buying either another power amp or an integrated amp. I'm thinking a budget of £600 - £700, and am quite happy to consider pre-owned and expect that is where the true vfm is to be found. I also currently use a Beresford Caiman as a DAC/volume control and would expect better results when using the fixed line outs rather than the variable ones if the amp was to be integrated with its own volume control. Any recommendations?