change amps or speakers

Hello majorc,

     Your description of your current system's shortcomings are remarkably similar to the perceived shortcomings I had with my system as formerly constituted, although I used more powerful ss amplification with my Magnepan 2.7QR planar-dynamic speakers. 
      I believe your  ET LFT8bs are also planar-dynamic type speakers that have the 2.7QRs similar strengths of having fast and detailed midrange and treble performance along with very good, palpable and natural stereo imaging qualities.  But I also believe they share similar weaknesses of having restricted rated bass extension, mine are only rated down to 35 Hz, and having rather poor bass dynamics. 
      About 5 years  ago, I bought and installed an excellent solution that  dramatically transformed my system by providing the solid,powerful, rhythmic, fast, detailed and smooth bass impact and dynamics, with a rated bass extension down to a flat 20 Hz, that I perceived as being absent from my speakers sound qualities.  The system is the Audio Kinesis Swarm system.  Here's an Absolute Sound review that provides a very accurate description of what to expect:

https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

     I'm fairly certain this system will perform equally well as a supplement to your speakers and dramatically transform the rhythm, impact and dynamics of your system.

Best wishes,
   Tim  

I have those same amps and they have much more power than you think. If you'd like to message me, I can tell you what I've used them to drive.  I've paired them with a couple of preamps and my main preamp is a Quickslilver linestage. But their wattage should not throw you; they are much more powerful than you might think.

I ask Richard Vandersteen that same question I owned 2ce SigII
He said you will get your biggest improvement  so now I have Quatros 
But I think you need to demo a preamp you are just not driving your amps enough 

Enjoy the Music
Tom

I'm re-thinking my comment after looking at the specs on that speaker. How low do they dip, impedance-wise?

@majorc
By chance are you in Sac? Familiar combo here locally. I’ve heard the LFT8bs on the larger 100w QS Mono 120s, and the smaller LFT16s on amps as low as 10w. In either case, neither were super loud but sure are musical. Neat speakers.

It depends on how loud you want to play them, and those speakers can be tricky if they are not placed out from the wall, very room sensitive.

The older 2014 review by AS indicated they preferred the 8bs with at least 100wpc. https://www.theabsolutesound.com/articles/eminent-technology-lft-8b-loudspeaker/?page=4

However, I’m also wondering if your DAC direct to the Mono 60s is not giving you sufficient output voltage/gain to drive the Mono 60s properly. I’ve tried a former DAC direct to my own QS amps and it did not drive them properly. Do you have access to someone you could borrow an active preamp from to test it out before bailing on speakers or amps?