Class G Arcams, have taken what Arcam do well - and added a drive and liveliness that removed the "pipe and slippers" sound signature that some models are accociated with. The A39 has enough output in Class A to make it both lively and musically engaging (imo).
I was going to suggest Hegel - but wasn't sure if it was a direction you wanted to go in....but it would be a good choice and is often paired with Harbeth. Other brands that might be of interest would be Creek, Rega, Pathos and Electrcompaniet.