Building the Audio Note Kit 1 SET amp...

We think we are zeroing in on the problem! More to come!

The de Capo's are 92 dB, with a 6 ohm minimum impedance - - pretty friendly to tubes. My 35 watt EL34 pp integrated amp can barely crank up on the dial (I wish the speakers had a little less sensitivity!).

It has been pointed out earlier in this thread that the actual sensitivity of the speaker is in reality 86 to 87 db. Jbrrp1 in your case your may have surplus system gain.

Jbrrp1,
Yeah my Manley EL-84 push pulls in triode mode (20 watts) drove the De Capo's plenty loud with no trouble.

FWIW, regarding what can be expected from a SET architecure as opposed to other tube based designs, my understanding about SETs in general, based purely on what I read, which is consistent with what I have heard to-date, is that its their midrange that make them special. They can do well on the extremes as well but it takes a fairly specialized approach to component matching with high efficiency speakers in particular for them to be able to "do it all", especially in the bass. Of course a smaller room helps to enable doing all that is needed practically in many cases.

I hope it works out with the Decapos. I'm still thinking there is a good chance from what I hear once the technical issues with teh newborn amp are sorted out.