Custom-ordered this amp from Blair Lamphear, designer/builder of Niteshade Audio.  Features sub-chassis mounted Edcor 8 ohm output transformers, variable feedback, 5U4G rectifier, 6SN7 splitter/predriver tubes, and the ability to use all types of 6L6 tubes, except the metal 6L6.  Power rating is a modest 15 wpc.  However, the amp showed absolutely no signs of trouble driving my 85 dB Harbeths to quite loud levels in my 12’ x 25’ room.  A very versatile amp.  Extremely quiet design, no hum or hiss at idle through 85 & 90 dB speakers.  The variable feedback changes the presentation from dark and warm to bright and forward, allowing it to adapt to your speakers and room acoustics.  Also, the bass presentation is dependent upon which output tubes are used.  Included are new Chinese coke bottle GCs, which provide slightly dry, tight bass, along with old Sylvania GAs, which provide a slightly fuller bass.  This flexibility enables the amp to be used successfully with speakers ranging from mini-monitors up to large horns.  A new 5U4, vintage 6SN7s, and IEC cord are included.  Asking $580.  I have 5 years of feedback on A-gon, and 11 years of feedback on ebay.

Not at all an unreasonable request, I should have mentioned it in my description.  When I purchased this amp, my intention was to slowly build a high-efficiency system, in addition to my main sys/HT McIntosh rig.  All of the usual detractors have since conspired to squash this from becoming a reality.  With so many other needs, if I were to commit more funds to another system, domestic tranquility will be severely compromised (diplomatic translation). Also, we're moving soon, and we won't have two rooms available for proper hi-fi rigs.  So, before I get too far into building the HE system,  I've decided I'll cut bait.

Thanks for the well wishes, Guy.  It took a bit of pride swallowing to finally act on the realization that I won't be able to do this amp justice any time soon.  I was considering pairing it with K-horns or Tylers, or even some fullrangers with sensitivity in the mid-90s.  What speakers are you driving with your NS-15?

Seeing your new gen NS-15 reminds me of a recent inquirer who was baffled that my NS-15 didn't look like the one on the Niteshade site, which happens to be the same version as yours.  Blair originally called the push-pull version like mine the 15, but he told me it actually put out 20 watts.  My understanding of how mine differs from their similar-looking NS-30 is that my amp was designed to operate with either the vintage lower voltage G/GA/GB tubes, as well as the higher voltage GCs.  Therefore, with either tube, it's rating is 20, rather than the typical 6L6GC's circuit design of 30 watts in PP.  That brings us to your new version of the NS-15, which is single-ended, and 15 SS-rectified watts or 10 5U4-rectified watts you mentioned.  Most of us realize a manufacturer reserves the right the modify their product at any time, but this inquirer just couldn't seem to get over that.