presenting an amplifier for all seasons...

KE ENGINEERING/ deHavilland Model 50A Mono Amplifier


"...The sound was perfectly beautiful. An Esoteric CD player into the deHavilland Mercury III linestage was providing the signal to a pair of the deHavilland 50A  Signature mono amplifiers which was powering a pair of Wilson Benesch's Curves, all the cables were Kubala-Sosna.

This was a room that I found myself returning to more than once, when I was tired of all the noise. Most importantly, it was a system that allowed you to really enjoy music."

                                      --Jack Roberts , DAGOGO , 2009 RMAF Report.


Engineer's notebook about the 50A 

       Design Highlights: 

 * Unique Interstage Transformer Drive. Full Triode mode and 45 watts. 

 * Twin Tube Rectifiers. Sweetness of tube rectification,  and very soft start. 

 * Choke Input Power Supply . Old School voltage regulation without fragile transistors.

 * Paper and Oil Signal Capacitors.

 * Tube Regulated Bias Voltage Supply.  Easy and stable bias setting with onboard meter.

 * Point-to-Point Wiring . Old School hardwired audio circuitry.

 *Heavy Duty Chassis .Fabricated from CNC machined parts-- from solid billet aluminum.

 *Conservative Operation of Power Tubes. KT88/6550 tubes operate well below 

                                                                maximum ratings. Easy on the tubes.

 * Cardas Speaker Binding Posts





Design Summary

*40 Watts RMS Output, 4, 8 ohms .

*Dual tube rectifier, high current power supply, very soft starting

*Choke Input power supply

*Interstage transformer final signal drive

*Triode wired KT88 output stage

*Tube regulated bias power supply

*Onboard bias meter

 *Dimensions 17-1/4"L x 9-3/8" W x 9-1/2" H, Weight 42 lbs.

Tube Complement:

2x KT88 (6550, 6L6GC, 1614, Kt90 are direct substitutes in the 50A )


2x 6CG7

2x 6CL6 

2x 6CK3 (9-HP pin basing)

50A Model and Pricing 

 US Retail per pair, (effective May 22, 2011  $10,800.

50A Show Reports  & Reviews

"though I've heard the Wilson Benesch Curve floorstanders ($9950/pr) many times before, I found

 that they sounded spectacularly good as driven by Kara Chaffee's amazing deHavilland [KE-50A]

 tube electronics. Nothing I heard at RMAF, save perhaps for the far more expensive Vandersteen/ARC system, could touch this rig for sheer midrange purity, detail, and three-dimensionality."                                        

                                                               Chris Martens, Feb 2010 The Absolute Sound


"deHavilland/ Kubala-Sosna/ Esoteric/SoundsReal Audio room. I have my reasons for voting this room "the best" and here they are. It played music for me. Its presentation was very big and wide and spacious , yet intimate. It was as if the music was being played just for me..."

                                                               Thad Aerts , The Hi-Fi Reader Magazine #11


"If your speakers can get by with relatively moderate should strongly consider auditioning the 50A monoblocks. Their combination of top-to-bottom balance , clean and resolving highs, magnificent bass and slam, articulate speed and PRAT, and gorgeous brocade of sound , seems to me very hard to beat. In fact, I couldn't beat them. I gave into the music, sold the Air Tight ATM-2 , and bought the review pair of 50A. They took me back to the future and I've never been happier with my system's sound."  

                                  Garrett Hongo, UltraAudio Magazine / Soundstage Network Apr 2009