@atmasphere - actually I did measure the dBA with a sound level app. The measurements between the two amps were essentially equal at the same volume setting. However, I also understand what you are saying because the SET amp "sounds" louder at the same setting. Interesting. Thanks.
300B SET Amp driving Wilson Sabrinas
Interesting experience to share.
In my home system I have a pair of Wilson Sabrina speakers normally driven by a Modwright KWA 150SE (Special Edition). On a lark, I replaced the Modwright with an Elekit 8600S 300B amp (Lundahl output transformers and Mundorf Supreme output capacitors) I had in another system.
The surprise, not only did the Elekit drive the Sabrinas very well (improved clarity and tonality), but at the same volume with the same input level as the Modwright! Using a passive preamp, when I set the volume knob on the preamp to the same point for both the Modwright and the Elekit it results in essentially the same volume from the speakers.
Admittedly I listen at moderate levels (SPL rarely exceeds 70dBA), but the sensitivity of the Sabrinas is only 88 dB. Who would have thought!!