Senstivity of Spendor SP1 and SA2 speakers?

[greatbridge]

While considering a suitable power amp to complement my AudioLab 8000Q I need to understand what approximate power I need to drive these speakers. I can't tell if they are super sensitive or moderately so. I don't think they can be super in-efficient because I note they can be driven to a loud enough state in my average size living room using an old NAD 3020e - which I think is rated at 40w/channel - with the NAD volume control at no more than 25% to 30% of its total rotation.

I suppose I'm trying to decide if an affordable SE vacuum tube amplifier would be power enough. Any comments?

 

[Arkless Electronics]

They are of average efficiency. They really need something much better than a 3020 (20WPC) as they are superb speakers IMHO. SE valve amps are not suitable...

 

[TheDecameron]

I've not had much success with SP1s and a reasonably powerful 75wpc pp valve amp. Had similar poor results with their S8s and said amp. Sound had what someone else called a "papery colouration". They did sound good with a powerful ss amp though.