Moving away from inefficient/low impedance speaker in order to move to a Tube Amp

 I have Harbeth C7's, which are a very nice speaker....but I'm not willing to spend the money on a high quality 100 watt tube amp. 

How much do you want to spend? What preamp are you using?

I had a 35 wpc Primaluna amp.  Got the low watt bug and bought a Decware Mini Torii 4wpc amp.  Kept my Ref 3A speakers ( rated at 92db eff.)

Other than not being able to bother the neighbors I got plenty of sound in a 12x20ft room open on the long sides.

Wouldn't mind a more efficient speaker but haven't seen one the trips my ticket.

Have a Grommes PHI-26 6 wpc speaker in a second system with 97db Klipsch Quartets  both sound great just different

We had some monitors like that here, they were a similar 87dB and with my 20W Raven Blackhawk had no problem driving them satisfyingly loud in my 17x24x9 room. The guy who brought them had also brought his 100+ watt SS amp. We were all surprised how those inefficient power hogs came alive with the Blackhawk.

It is good you are figuring out something I have used as a speaker buying guide all my life- avoid low sensitivity speakers, they limit you on amps. But unless your room is huge or you rock out a lot (not likely, Harbeth after all) then you will be fine with any tube amp 20W or more.

As a general rule of thumb all amplifiers regardless of their technology make higher distortion into lower impedances.

       Agreed!

Have not done it but done a lot of research investigating the possibilities. Class D amps have kept me from having to go there (tube amps) to-date.

Not in general interested in large bulky speakers required for best performance in general with low watt tube amps.

However, to test the waters on a limited budget, I would likely go with Klipsch Heritage line and pick a tube amp from there. Could be Heresy, Forte, or Cornwall depending on specific room and what would provide the most flexibility there. Would also consider Spatial Audio in the right room or Fritz speakers (easy load to drive) for something more compact. I would also probably at first be inclined to give it a go with my existing Ohm Walsh speakers, but would expect to need at least 20 watts or so or more.

With a limited budget, practically, it would be hard to talk myself out of trying this

Amazon.com: Willsenton R8 KT88/EL34 x4 Tube Integrated AMP Power Amplifier Headphone (Silver) : Electronics

as a first stab. Lots of good reviews, good build quality, flexible, value.

Beyond that, if needed, on a grander budget, amps I have heard that I would strongly consider come from companies like Audio Research, Rogue, Jolida/Black Ice, Conrad Johnson, Linear Tube Audio, Audio Note and I’m sure several others.