Who's using Harbeth with tubes, what speaker model and how many watts per channel?

@atmasphere 

Does the zero add-on to an OTL amp basically then function as a Berning type ZOTL amp which provides that properly impedance-matched tube output stage to the loudspeaker? 

@aj523
In terms of getting a match to a low impedance load, yes.

I've heard my 40.1's and now 40.2A's with Primaluna and Cary tube amps and thought they made lovely music, but once I switched to solid state amps (LFD NCSE and now Hegel H590) I am much happier with the sound.  The 40 series speakers are hungry for power, and the two tube amps I mentioned did not provide this as well as the Hegel or the LFD.  

@atmasphere 

thanks ralph your perspective is very helpful!

My favorite Harbeth/Amp combo was SHL5+ being driven by an Air Tight ATM-2 amp. 

The Air Tight makes approx. 80W, I used a Lampizator Big 7 as a preamp and DAC. 

The most enjoyable sound I've had in my home.