That’s the right ratio ... tube amps due to producing even order harmonics when clipping still sound great. So halve the solid state wattage to get an equivalent output level provided the impedance of the speaker isn’t atypical. The first time I checked out the RAAL website, it stated a 150 watt/ch amp was required. When I visited the site earlier today, I noted the wattage figure was down to 100/ch. That’s why I asked @RAAL requisite Alex if they had any experience using a lower powered tube amp. I love ribbon drivers. I owned Apogees in the 90s and loved its sound. I now have Raidhos which use a proprietary ribbon tweeter, the best high frequency transducer I’ve ever heard. I believe my Luxman can use KT90s with little bother since it’s a manual bias design with a meter. Your monoblocks should do the job. Please post your findings after you get the SR1a, I’ll be very interested in your thoughts ... Last thing, I love well designed audio product, and the SR1a has a killer look to it—I love the carbon fiber build. This hobby is so crazily addictive. I just bought a final D8000, its new top end planar, a month ago and they are fantastic sounding; now a month later I’m already fantasizing about a new TOTL headphone.