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A Trip Down Memory Lane – The Master Amplifier Builder
If there ever was a genius in home audio it would be David Berning. Fortunately I met David years ago and heard his original prototype power amplifiers. Some of my technical friends said it did not measure very well. To me it sounded better than any other amplifier on the market, and today’s Berning amplifier is no exception. That is to say that it is exceptional, and unlike any other amplifier manufactured today or that has ever been manufactured!
Do amplifiers really sound all that different. Yes, and the best ones sound significantly better than the competition. When I bought my Magneplanar’s I soon realized that great speakers reveal flaws in amplifiers. I heard about David Berning having a pair of Magneplanar’s like mine and that he was driving them with his own hand-built custom amplifier. Luckily, I was invited over to his home to hear his system. The Maggies sounded far better than I had ever heard them. There was just no question about that. David was a gentle, modest genius who worked for the US Patent Office at the time. Fortunately he was able to get his own patent for what has become the world’s best home audio amplifier.
Why haven’t you heard of the Berning amplifier? Perhaps you have. The amplifier does not have wide distribution because few people are able to really appreciate such quality today. Today’s source material is not that good, and frankly, not very many people are looking for natural, transparent sound. The amplifier is expensive, but it can justify its cost for the well-heeled audiophile far better than today’s overpriced and under performing amplifiers.
Established in 1974, The David Berning Company manufactures vacuum tube hybrid audio amplifiers based on an unique Impedance Converter that replaces the traditional audio power output transformer and greatly extends and improves amplifier performance. His technology is called “ZOTL” for Zero-Hysteresis Output Transformerless.
Berning amplifiers using the ZOTL technology exceed the performance of traditional OTL tube amplifiers by properly matching the tube impedance to that of the speaker. They convey the musical transparency of tubes without the limitations imposed at the frequency extremes by audio output transformers. This limitation at the frequency extremes is a major contributing factor to what some negatively call “tube sound”. ZOTL extends the desirable musical transparency of tubes to the frequency extremes and provides the quickness of the high and low frequencies that are cherished by those who prefer solid-state amplifiers.
Why are the Berning Amplifiers state of the art? First they sound better than anything else. Secondly, they spec out as state of the art. His latest amplifier is the 211 / 845 Monoblock Amplifiers (named for the choice of output tubes that may be used). If offers:
Fully automatic biasing for either tube.
Output Transformerless 60 watts Class A.
Constant output impedance over entire audio spectrum.
Mono Block format. Low noise floor for high-efficiency speakers.
Both balanced and single-ended input.
Zero feedback.
Proprietary switch-mode power supplies with high energy storage
Full Power-Factor Correction for global plug n’ play operation.
No adjustment is ever required.
What do they sound like? It is hard to describe. Let me quote Dick Olsher of The Absolute Sound:
The other attribute that set the Berning apart from the crowd was its immediacy—a lack of veiling that created a strong sensation of being able to reach out and touch image outlines. This combination of speed, control, and immediacy resulted in a level of clarity only a handful of tube amps could match. It was able to generate a cohesive, spacious, fully 3-D soundstage with excellent transparency and fabulous image palpability.
The amp has incredible speed and dynamics. It makes other amplifiers sound compressed. So much more could be said. If you are seeking the very best and have the money, then the money would be well spent, provided you have the best source material and speakers like the best Magnepan’s (or maybe Quad’s, B&W’s, KEF’s, or Spendor’s.)
AUDIOGRAM II 
Berning’s ZOTL technology is available for musicians in the Milbert GAGA guitar, bass and instrument amplifier ( http://milbert.com/gaga ), and it is also available in a reintroduced (version 2.0) headphone amplifier called the microZOTL ( http://davidberning.com/products/microzotl )
Thanks for the info Michael. Can you share how his technology may have made some sonic impacts with musicians?
I can. I am a violinist. And I listen to Berning. Egidius Streiff, violinist / artistic director streiffzug.com
Great to hear it!
Which is Mr Berning’s choice with Soundlab A-1 or 845’s?
As much as i like the ZotL amps , if you have electrostatics please use direct drive OTL amps.
Nothing beats ESL’s with direct drive amps in dynamics together with realism and microdynamics !
I use them with my Acoustats and Beveridges.
If correctly designed they will last “forever” including the tubes (i have build the amps 12 years ago and the original tubes are working fine) .
Hard core, Frank! I remember the Beveridges. I think the Berning amps excel on Magnepans. Matching amps with speakers is the key, as you have said.
Matching is key (also between amps and sources, mostly forgotten).
I also have built many Futterman based OTL amps in the past and these work fine on Tannoys etc. But now i prefer the Zotl amps as these surpass any other OTL design, period.
At this time i also use a Siegfried clone on Tannoys, a very nice match indeed.
Now i am working on a Quadrature Z clone but i have not yet decided on the tubes i will use for this one.
I will keep you posted if you’re interested.
Thanks for the info Frank. You might find this interesting. We once compared an REL Precedent tuner with a Marantz 10B. Futterman had installed a FM multiplex in the REL because the original tuner was mono. This modified Precedent tuner was the only one that ever gave the 10B any competition sonically.
If it wasn’t for Harvey “Gizmo” Rosenberg, i would have never heard of Julius Futterman.
I am glad i read his blogs as he also introduced David Berning as the new “King” of OTL designers.
Unfortunately other great designers are totally forgotten or never even mentioned.
We all know of Nelson Pass or Tim de Paravicini but who has heard of Jim Strickland?
Hello Frank. I’m also using a ZOTL (Berning) amp with Tannoy speakers. My Berning amp is similar to the Siegfried amp (it uses 811-10 power tubes). Paired with my Tannoy Churchill speakers, it makes beautiful music indeed.
As you may know, Linear Tube Audio is also making equipment using David Berning designs, at more affordable prices (for a larger market) than the products David makes himself.
Would love to hear your system.
Yes, i know of LTA. The difference is the use of the output tubes (G2 driven in David’s amps in case pentodes are used and the dc coupling of the tubes to the speakers) as far as i can see. Also David uses now his Quadrature Z update that will increase the duty cycle of the square wave on the tubes (doubling the frequency). In this way he also can connect the speakers between 2 impedance converters ( not to ground increasing the voltage as current is sufficiant). Unfortunately i have not yet started on my own implementation of the Quadrature Z amp as i mentioned earlier.