OHM Walshes almost always sound fuller with dedicated amps that generally deliver more current, but I would have to think 80w/ch in general should do a decent job.
I've run larger OHM Walshes off an 80w/ch Tandberg receiver in the past in a much larger room with very good (but still not optimal) results.
I've run larger OHM Walshes off an 80w/ch Tandberg receiver in the past in a much larger room with very good (but still not optimal) results.