Amplifier recommendations for 86 dB Sensitivity Speakers

I have Janszen speakers 86db at 6 ohms. I use a single LTA ZOTL40 to great effect. The current this amp outputs has more than enough power to make these speakers sing. You could of course use two of them as mono blocks.

You have a nice system. The decision will be made by room size. A larger room will take more power for the same experience as a small room. I run 30wpc from EL 34s into 89db sensitive speakers. I am using the system in a 12 ftx15 ft area. I'm only 10ft from the speakers. There is windows with cutains in back of where I listen and a 25ft ceiling. The is open space leading to a dining room on one side. This is not an ideal space, but it's still sounds great. The room is very important, distance from the system and how far the sound needs to travel with impact realism of the experience. Sometimes experimentation, moving things around will greatly improve the sound.

I'm running a system at the moment in a 13' by 16' room, with Dynaudio Heritage Specials (4 ohm, 85dB/1watt) and a Conrad Johnson Classic 62 SE power amp. I don't listen louder than 80-85 dB peaks as a rule, hoping for long term hearing preservation and all that. So in essence I'm using that first watt to good advantage, with the other 60-70 watts as headroom. This room has a door, and it can be closed to shut out flow to the rest of the house. It's a sublime combo, and exceeds the systems that I've run in this room over the last few years. I can't support the ideas that tube amps are automatically going to fall short in a case like the OP presents to us. 

I've tried the CJ tube amp downstairs with the 2ceSigs as well, and it's more than fine. The presentation is great and that room is a little larger at 14' x 18'  with significant connecting doors and openings to other rooms in the rest of the downstairs. Here I do prefer the 200 plus wpc into 4 ohms of the available solid state amps. 

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.