Tubed Monos for Focal Aria 948s

+2 for Quicksilver Mono 120s. Got some too. Love them :)

Also, I helped my sister to acquire Focal 948s and for her we chose a simple 100w Peachtree integrated (with tube input) for her family room. Goes plenty loud, and I’m certain QS Mono 120s would be plenty, I’ve heard them with large 7 foot tall IN-effcient electrostatic and large multi-driver speakers. Mono 60s could work too, with a bit less grunt than Mono 120s. 948s are known to be bass heavy so pick your poison with QS Mono amps.

Mono 120s are what I use for my own multi-driver electrostatics in my main system now. Takes a while for tubes and caps to burn in. Once that happens, they really take on a nice smooth sound.

Mono 120s have the finesse of lower power amps with large transformers and proper circuit and plate voltage to drive the KT150s.
I’m a 40-year mosfet solid state amp guy and love these amps. Mike did a really nice job on them, switch on the front and AC/speaker on the back, with KT150s and quality build and I’ll say it again, large-quality transformers in a well known proven circuit design. They run 12AU7 input and 12AT7 drivers, so tubes are not crazy expensive if you want NOS or boutique tubes. I’m running NOS 1960s Mullard input/drivers elevating the sound to true high-end, totally 3-dimensional, nice midpoint sound stage, dead quiet. Again, need to burn them in 200+hrs.

Mike’s standard Linestage preamp (non-remote) version is a nice preamp for them, great value too. However, I run a different 6SN7 based preamp (already had it), and it pairs sooooo nicely with these Mono 120s. Comparable CJ KT150 based amps are $19k, over 4x the price. I’d put these up against it all day long. Value$ !!!

Keep the bias at 40ma and they run COOL! Any of my former Class-A, or better Class A/B solid state amps ran warmer than my Mono 120s. The more I listen to the KT150s, the more I really like them, more than I thought I would and I tend to generally like EL34 sound. The KT150s have more top-air, more bottom end, and the right amount of midrange without being syrupy in these amps. Mike nailed it with Mono 120s for my custom speakers.

...my thinking is that the warmth of the tubes may help the tonal balance. Is this is incorrect?

No, not incorrect but I will say there may be other areas to mess with before jumping to tube mono amps to remedy the leanness. Sure a pair of tube mono amps with smooth sounding EL34 tubes can "round off" the highs a tad to accentuate the bass some but you may have other options to try before you try other amps... tape a paper towel over your tweeter on your speakers as a cheater simulation test...: heheh.

I took a look at your amps, torroid transformer, notable power quad caps and while don’t know much about your amps sonically - but know a few locals with them that did go to tube amps later but for sonic reasons OTHER than adding the weight and fullness you seem to be looking for (below 200hz) with your Focals. With that said, I think you might look at some other areas if you want to keep your Odyssey amps. They are kinda nice. Perhaps restarting with 1) your preamp/upgrades, preamp tubes, preamp caps and 2) maybe even some softer and more rolled off interconnect cables next to cheat some...a tradeoff some times (chat via private message), gotta few ideas there too from my own hybrid tube preamp / ss combos. And, if you have not already done so. 3) maybe look at adding a little REL subwoofer is a nice cheater fix to fill in that dip. They can sound nice. I build my main speakers and custom subs and a good sub can help fill that void particularly for low volume level listening and permit your mains (to work less hard) to resolve better too in a large room. Look at what some of the more expensive Wilson Audio speakers are doing the past decade, see the lower half of he speaker :) Just a few other thoughts, feel free to send a private message. Gotta a few other questions for ya. Your preamp has the triple 12AU7s per side, correct - or older version. The new PL labeled input tubes in those preamps look like rebranded PSVANE tubes, sort of. Also noting the Mundorf caps in the newer version pre - I run those same caps in a tube DAC, but there are other caps that are warmer, less tinny, the EVO supremes are fuller, IMO. You may have other areas to work on IF you keep those amps you have now.