How Much Power Do Vandersteen 5a's Really Need?

I've driven mine first with mono DR8s, then with a Luxman 110W integrated, and now with Music Reference RM9SE, 100 W/side.  All worked fine.  

I had the 5a for years before the 7’s. I used a variety of amplifier: Ayre , McIntosh, an ARC Ref 75 se was lovely....

how big is the room ? How loud do you listen ? Hint to set the EQ and set them up properly you need an analog SPL meter from RS.

congrats on what is still a world class speaker !!! Enjoy the music

yell if you need setup help

Thanks for all of the input. And thanks very much for the offer of help Tomic, I may reach out for setup assistance if needed. I do understand that the manual has a lot of setup information per a discussion I had with Richard Vandersteen, about these, yesterday. Hopefully that is of significant assistance. 

The room they will be in is very large, The listening area is about twenty feet wide by 15 deep. However, this is only 40% of the "great room" that the listening space is located in. Behind it, is the fireplace area, the dining room, and the kitchen. The ceiling are also vaulted.

I'm hoping to power these with my wonderful Conrad Johnson ARTse tube amp, with 140wpc per side, and a ton of gain. 

Listening volume will range from relatively quiet acoustic and singer songwriter selections, to now and then, loud, live rock concerts at something like at least semi-realistic volume. 

people generally seem to be throwing a LOT of power at them. Am I missing something? 

Yes: the logarithmic nature of power. 10 dB doesn't sound like much but its TEN TIMES the power. 

Look at the spec- they are 87dB. You can let these guys blow smoke up your a$$ or you can save a ton of time trouble and $$ and cross them off your list.

Never buy speakers under 92dB. Just don't.

Although I am firmly entrenched in the "more efficiency, the better" camp, 140 tube watts should be fine to drive these speakers.

Oz