I also have the Duo (225 era) supplemented by a pair of 15 inch subwoofers that are DSP’d. The speakers mesh wonderfully with SET amplification and require a little fiddling to get them to play well without being too reticent in the bass or lacking in cohesion between the integrated woofers and the midrange horn. Due to their efficiency, you can hear gremlins in grounding and power that may be masked in other systems. These speakers made me work to get a very low ’noise floor’ but it was worth it. Differences in recordings, cartridges, VTA settings, etc. are pretty obvious. Get them set up just so and they can be marvelous. My system page here has some pics of the set up installed in Austin, TX.
PS: on this era of Duo, there is no crossover on the midrange horn which lends it an immediacy that can be quite lifelike with the right amp. You connect the amp output directly to the midhorn, and then run jumpers to the tweeter and woofer module. I've been using Lamm ML2 for a dozen years and they are very synergistic. I came from electrostatics and have always been about the midrange first. Though I keep a restored pair of old Quad ESLs in a vintage system (a pair that I have owned since 1973!), I don't feel like the midrange in the Duo is compromised by comparison.
PS: on this era of Duo, there is no crossover on the midrange horn which lends it an immediacy that can be quite lifelike with the right amp. You connect the amp output directly to the midhorn, and then run jumpers to the tweeter and woofer module. I've been using Lamm ML2 for a dozen years and they are very synergistic. I came from electrostatics and have always been about the midrange first. Though I keep a restored pair of old Quad ESLs in a vintage system (a pair that I have owned since 1973!), I don't feel like the midrange in the Duo is compromised by comparison.