Given the sensitivity of your speakers, a definite yes in the bass department. You are working with over double the power out of the gate (18W/ch vs. 38W/ch). The power is immediately apparent with speakers that require it. The bottom end has more substance and authority. The massive Churchill's can handle 500W and although I never felt there was a significant depression in the bass, Roger owns a nice JL Audio F113 that he would turn on now and again for demanding classical pieces. It was more of an experiment with the Topaz or Sapphires and when comparing the Tannoys with the Zu's or Coincident speakers he once had, the latter two were simply much more nimble (particularly the Zu's) because of their sensitivity, but without the powered woofers on the Zu's or the addition of the sub with the Coincidents, there were times that one might argue the lack of sub was noticeable. For us, (Roger and I) mainly listening to jazz and blues records, we rarely had the sub on, even with the Tannoys (those things have large dual concentric drivers that can really push the air) being a bit tougher to drive. We simply never felt a driving need.
That is until the Rubies were introduced into the system. Again, my impressions are meant to be taken in the context of an intra-comparison vs. an inter-comparison of other products. I have felt for years that the Sapphires are already a pair of wonderful amps that give far more than the 18W rating might suggest. The bass has always been there, deep with authority. Tight and fast lacking what some have said is a tell tale bloating of 300b SET designs. Pair the good bottom-end with a smooth and linear mid-range all the way up through the treble to achieve wonderful air and space around each sparkling note as it trails off (I'm convinced SETs do this best) into the distance... Just wonderful! So that's the Sapphire, now, subtract any notion that the bottom end needs help. Relax as one hits the highs of a brash high C on a trumpet. No squinting. No curled shoulders. It sounds pure and right. Not recessed and not bumped. And the mids... oh the wonderful mids. You get that with the Sapphires already, but now the coherence is better because of the greater control. At least on the Churchills, the cones can start and stop on a dime while providing the power to get that air pounding into your chest on the other side of the room. I feel it in the floor, through it, when I listen to his system now. Before, I needed the sub on to get that. Again, this isn't overdone. It's just there as it should be, with those speakers. For speakers in your sensitivity range, I would predict a similar bump in performance. The power supplies on these monos are incredible and as per his usual kit, overbuilt. There are power reserves after the power reserves have kicked in. We couldn't drive them to half their capability without overpowering the room. That or having the neighbours call the cops :)
The cost differential is substantial going from the Sapphire to the Ruby. For that amount, if you can swing it, I would suggest flying into Ottawa and having a listen. Roger has a practically new set of Sapphires well burned in. They were traded for a Ruby :) He has the Ruby as well of course, and given the lead time to build if he doesn't have a new pair ready to go, you would have the luxury of hearing it all before you buy.
I have a decent amount of experience with various rigs of all price and performance ranges. For my tastes, I had long ago determined SETs were the shortest distance to audio euphoria. Having listened to a dozen offerings, Wyetech monos of any model were getting me closest to what I wanted with the greatest frequency. I circled in on the Sapphires and that will likely be my final decision. If I could swing it financially, I would race towards the Rubies and never look back. More time to investigate music. No more gear chasing after that. I already have the Ruby Pre, it should would be nice to have the Ruby Monos to mate with it.
