DR. Harvey "Gizmo" Rosenberg

PhG, PhD, PrfC, PhC, ROW

His Wholey Dudeness
The Guru of Gizmos
Thermionic Techno-shaman
Guildmeister, The Triode Guild
Grand Master of Camouflage
Exalted Punjab of Wrenchers
Grand Wazir of Speakermaniacs

PO Box 4476, Stamford, Ct. 06907

203 358-8142 fax 203 359-8198, E Mail: drgizmo3@earthlink.net

 

My fellow thermionic artists,

Because I am a subscriber to Glass Audio I discovered the work of Nobu Shishido. I was so impressed by his ideas that I started to correspond and talk regularly to this grand master of the triode. As a result of this dialog I was privileged to be the only man in America who had a long term listening experience to all three of his WAVAC SEDHT amplifiers, the 4033, 300B and 805. I listened to them on my ultra-hot rodded Tannoy Westminster Royals which are made for the Japanese market and use a fourteen foot folded horn and are 100 db efficient. Because I use a tube crossover I used various combinations of Nobu’s amplifiers on the tweeters and woofers.

Let me explain the difficulty of describing this experience. Clearly Nobu’s artistic intent is to take us to a musical territory that is so refined that there is no conventional language that can describe it....this is the job of the audio artisan...to inspire us to explore the ineffable.

The meaning of his unique transformer coupled circuit is NOT the elegance of the circuit but the completely unique way music emerges from this circuit. As he claims there is no way to measure or explain why his interstage transformer creates a unique form of musical beauty.....but let me stumble at that effort.

The word I have created to express the emotional and physical joy of design is "whole-osity"...there is a physically tangible sense of harmonic completeness that makes other circuits sound ragged. And that includes my own very sophisticated SEDHT 300B. The unique qualities of single ended amplifiers (which you know and love) are amplified with his design. For example: the musical wave front of music from top to bottom octaves moves through the room with an organic integrity that is absent in almost every other tube amplifier I have experienced...over thirty years. Perhaps I should say there is a dynamic proportionality that is so spooky that your goose bumps will get goose bumps. When listening to voice through his circuit and then switching back to a conventional SET it is as if you went from a SET to a PP design. The Achilles heel of all SET designs is below 200 Hz, but in the case of Nobu’s circuit from 400 Hz down there is a tight voluptuousness that RC coupled circuits don’t have.

For my personal triode agenda, there is an artful wall at about ten watts. After that you get more power, but not more refinement. Nobu’s 300B amplifier was my favorite both on the tweeters and woofers, but the combination of the 4033 amplifier, which I consider the most beautiful tube amplifier in the world, on the tweeter and the 300B on the woofer got the most standing ovations from my friends. The combination of the 300B on the tweeter and 805 on the woofers made my friends in the rock and roll business go unstable. The 805 is a completely challenging experience because after you have heard a fifty watt single ended amplifier of this refinement you wonder where push pull fits into the thermionic cosmos...especially if you are a triode rock and roller, dudes!

I am also suggesting that if you want to experience the concresence of directly heated triode harmonic whole-osity you must remove your speaker’s crossovers from between your output transformer and driver. Your SET amplifiers will leap to life...be more dynamic and lucid...which is why a tube crossover is an essential tool for exploring triode mystery.

And it is unfortunate that you can’t see the physical beauty of these amplifiers. They are sculptured out of solid billets of aluminum to be literally "gems of the audio arts". I and my friends were thrilled just to star at them glowing in the darkness. Most commented that they looked like religious shrines, and they are.

Nobu has done the American audio artists a great service by sharing his spirit. When the history of the modern audio arts is written he will be assigned the role of a great explorers.

My advice: if you want to travel to an exotic place of musical splendor, don’t call American Express, try Nobu’s circuit...and send me a postcard and some fruit.

Dr. Harvey "Gizmo" Rosenberg

Guildmeister, The Triode Guild

Thermionic Techno-shaman

 

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