Amplifier recommendations for 86 dB Sensitivity Speakers

Sensitivity is usually specified as SPL at 2.83 volts.  I guess to be precise it is at 2*sqrt(2) = sqrt(8).  From ohms law (etc.) (V^2)/R yields 1 watt into 8 ohms, 2 watts into 4 ohms.

If you get 86 dB at 2 watts, then 4 watts => 89dB, 8 watts=> 92 dB, 16 watts => 95dB, 32 watts => 98 dB, 64 watts=>101dB.

101db=> deafness.  Indeed prolonged exposure at or above 85dB is dangerous.

IMHO 70 watts is ample for your proposed speakers.  The most I have had in my current system is the 50 watts from a Pass Labs XA25 into my 87 dB spec Rockport Atrias, good solid state DOES double into 4 ohms as transistors are current sources.

Currently I have single ended 2A3s (perhaps 4 watts) driving those speakers, exquisitely!  My room is about 20x40, I listen at something over 12 ft. from the speakers.

It might depend on your chosen music genres.  Slam, impact, crushing crescendos are not relevant to my listening, I value timbre, clarity, details - the shape of the notes, and emotional content.

Having owned the Cayin A88T, the close cousin to your A100T, I can tell you the amp will drive them fine at moderate levels. However, dynamic peaks will become a bit flat sounding above 80dB average (measured at your listening position). It won’t harm the speakers because tube amps clip softly. You’ll just notice that at some point the amp quits making the speakers any louder and the dynamics suffer. 

Some potential good news is that the circuitry of these Cayins is perfectly capable of handling KT-120 tubes, and the amps sound more powerful fitted with those. The  bad news is that apparently all the more recently, post-Ukraine war manufactured KT-120s cannot keep a steady bias according to the guys at Rogue Audio. I don’t know how much stock to put into that claim but it makes me wary of buying any 120s without knowing their manufacture date. 

I would probably go with a solid state amp for those speakers. But perhaps you would be best off auditioning a variety of speakers somewhere and choosing a pair based on listening rather than specs and reviews? I realize that can require a lot of leg work but it could end up saving you money and hassle in the long run. 

FWIW, one SS amp that I find is very musical and way underrated is the original THX-certified Parasound Halo A21 (not the 21+). It can drive any speaker, is musically engaging, and similar to tube amps, its distortion is second order dominant. I have owned several amps that should be better according to price and reputation but in practice are inferior. The key to getting the most of this amp is to pair it with an ultra transparent preamp and source. A preamp like the Topping A70 Pro (headphone amp/preamp) or the Benchmark LA4 (if you simply want to spend more), and say, a DAC like the Topping D90 Discrete. Otherwise, with lesser preamps (most), the A21 sounds a bit too warm and homogeneous. 
 

Technics has gone from mass-market to high-end, keeping its toes still wet as an iconic turntable maker as well. I would think you would want to look at their amplifiers, which I imagine would work well with their speakers. The SU-G700M2 looks very suitable and well-equipped, with a DAC for its digital source inputs. Alternatively, you could consider the Yamaha A-S2200 (or the A-S1200 and A-S3200). No DAC, but excellent and capable with classic design and  traditional preamp controls. 

Quicksilvers 120s with kt150s 

Importantly and often overlooked is the profile of the impedance curve. These curves can vary typically from 2 to 25 ohms across the entire frequency range.
It would be  nice to get a measurement of the actual impedance curve to see if indeed it does dip down to 2 ohms .
Seems like the more exotic the design, the more varied the impedance curves are.
Check out the specs for the Nilai 500 monoblocks and you will see why the finest class D Amplifiers are acclaimed for their bass control and musicality.

Nilai 500 Specifications

• THD+N:  0.00015% (-116 dB) @ 100W / 4Ω / 20 – 20.000 Hz
• 260W  @ 8Ω, 1 kHz, THD < 1%
• 525W  @ 4Ω, 1 kHz, THD < 1%
• 500W @ 2Ω, 1 kHz, THD < 1%
• Frequency response:  0-70 kHz
• Output noise:  9.5µV @ 11.8 dB gain
• Gain adjust in three steps:  11.8 dB, 21.8 dB and 27.8 dB
• Signal to Noise:  134 dB
• Input Impedance: 47 kΩ
• Idle power:  14 W typical