I owned Avantgarde Duos for three years and have owned Avantgarde Meta Primos for the past 15 months. I owned and demoed many of highly touted tube amplifers (Audiopax, Art Audio, BAT, Cary, Wyetech, Audionote and etc.)that are known to sound good with Avantgarde loudspeakers. I recently purchased Avantgarde's new Model 5+ integrated which sounds very good with the Meta Primos. I demoed the older version of the Model 5 that was introduced a couple of years ago and absolutely hated the way it sounded. The new Model 5+ version uses Black Gate Capacitors and surprisingly sounds very good. I demoed First Watt's F-1, F-2, and the Aleph J with my Duos and then with the Meta Primos. The Aleph J sounde the best but still had a little bit of that solid-state forward edge that I did not like. Both the F-3 and Red Wine Signature 30 are on my list to demo, but I'm pretty happy with the sound I'm getting with the Model 5+. Who would have figured?