Airtight writes: "Our project started from a simple question. "How can we enjoy a beautiful sound of triode tube with modern speaker?" We started by revisiting characteristics of 211 based amplifier as well as modern loudspeakers. A rediscovery of "Local Negative Feedback (LNFB)" which we adopted on our latest 300B based amplifier has led us to realization. This LNFB utilizes feedback signal from a plate of 211 tube back to first stage. This LNFB technique were used in genesis era of tube amplifiers such as WE91, however it has been long forgotten." 

"AirTight matched this technique with modern high quality output transformer. This configuration offers vividness and thrill of the 211 tube in broad sound stage with depth. The LNFB also offers appropriate damping factor to 211 tube which can only provide damping factor of approx. 2 when used without NFB. 

To preserve pureness of 211 sound, we avoided use of Transformer Drive or Output Tube as a driver for the tube. 12BH7 in cathode follower configuration has been adopted for drive stage."

• Single-Ended Triode Tube Amplifier 
• Class A 32W Output 
• Local negative feedback loop for a good damping factor as well as vast soundstage and vididness & thrills in sound. 
• Selectable RCA/XLR input (both unbalanced) 
• 4.0.180, Speaker Out (Can be configure to have 16.0, at factory) 

Allowing wider selection of matching speakers while preserving pureness of SET 211 tube sound.