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TRUTH IN AUDIO PAGES

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Development of Improved Amplifiers

I began designing and constructing vacuum tube and solid state amplifiers starting back in the 1960's. By the mid-80's, this was a serious hobby, getting most of my spare time. Upon returning to Canada from a trip to the South Pacific in 1991, I decided to devote more of my time to the creation of amplifiers and loudspeakers of higher performance. This quest spawned, and was spawned by, creativity and serendipity.

The Non-existence of the Theoretically Ideal Amplifier

The theoretically ideal amplifier is an amplifier which, connected to a theoretically ideal speaker and fed with an undistorted signal representing the musical acoustic pressure, creates an exact reproduction of the original musical acoustic pressure from the speaker. As simple as this sounds, neither the required information transfer functions nor the configuration of the ideal amplifier, nor the definition of an ideal speaker can be found in any existing literature on the subject of audio reproduction. Audio practitioners do not agree whether planar electrostatic speakers or cone speakers are better. They have not been able to correctly formulate the theoretical requirements of an ideal amplifier, which would be intrinsically connected with the physical characteristics of the driven loudspeaker.

The 1895 Flying Machine Business

The Wright brothers, in 1903, achieved the world's first successful powered heavier-than-air flight. At the time of this flight, and for a couple of decades prior, there existed a thriving world-wide business in the creation of so-called flying machines. None of these flying machines could actually remain aloft for more than brief periods. Lots of money was spent building flying machines and there were lots of experts and there were books of expertise on the subject. For example, there was a book on airfoils by a German experimenter who had died in a glider crash. This book was considered the bible of airfoil design, just as the Radiotron Designer's Handbook is today considered a bible of tube amplifier design. One reason none of the flying machines flew was that the bible was wrong. The Wright brothers had a good grasp of the essential skills: physics, and the ability and confidence to experiment with innovation. They invented the wind tunnel to assess airfoil designs and quickly discovered that the bible had been wrong; they discovered an efficient airfoil. My point here is that the Wright brothers were the first to apply physics and innovation to a problem that had hitherto been the subject of blind tradition. The result was success.

The Present-day High-End Audio Business

Almost any blindfolded lay person can readily, and accurately, tell the difference between the sound of an acoustic guitar played six feet in front of them and the sound of the same guitar, recorded with the best recording equipment, and played back through the most expensive, or even the "best sounding" high-end audio system. The truth is, after hundreds of thousands of man-years had been spent on the development of audio systems, there was not one audio system on earth that sounded anything like the original performance. The state of high-end audio today is just like the state of the flying machine business in 1902: none of the flying machines could actually fly and none of the audio systems sound like reality. That fateful day in 1903 when the first flying machine flew was yet to arrive for high-end audio.

How to Solve the Problem of Real-Sounding HIFI

People have consistently made the error of considering audio to be essentially an electronics problem when it is in fact a physics problem. Not only is it a physics problem, but it is a cultural problem in that everybody is chasing short-term profit, whilst development of the ideal audio system is not a short term project. What was required to create the world's first real-sounding hifi system was the rigorous application of knowledge of physics to a problem that needs physics in order to be solved, and inspired innovation to develop the practical techniques to implement the theoretical findings.

A lengthy study of books from the original era of vacuum tube amplification produced no useful results, as the COMBINATION of amplifier and speaker was consistently ignored. The design of an amplifier and the design of loudspeakers are consistently treated as separate problems, and the individial treatments, regardless of depth, are simply wrong. In reality, the problem is to convert an electrical signal into a sound wave where a physical characteristic of the sound wave, either pressure or velocity, is an undistorted image of the information signal. This simple truth has never been carried through to the logical design implications.

To conclude, it seems a reasonable statement that in the entire history of radio, hifi and electronics, there is no evidence of serious consideration of what amplifier and speaker designs, IN COMBINATION, would be ideal, and therefore eternal, beautiful, and most importantly, capable of reproducing sonic reality. There has been no evidence of the creation of an amplifier/speaker combination that is based on the needed fundamental truth.

After twenty-five years of constant work, both design and experimental, I have been able to more clearly define a higher performance amplifier. This effort is based on faith that the universe is creating beauty, and that those who use their native creative skills will come into resonance with the infinite creative energy of the universe.

The ideal amplifier can be seen as a form of time machine. There are two ways to effect travel in time. One is to move part of the present into the past, and the other is to move part of the past into the present. The ideal amplifier is capable of the latter form of time travel, as it enables the recreation of sonic reality from an earlier place in time. One of my criteria for evaluating system performance is the degree to which I can feel a connection with the musician playing the music. I feel that the original performance is affected by listening to it, both at the time the music was performed, and into the future from the actual performance. Thus, if the system performance is sufficiently high, a real connection with the performer may be felt by the listener, just as though the performance is live. This connection appears to be independent of the actual span of time between the recording and the playback/listening. This can modify the original performance, according to quantum physics theory.

The identification of the ideal amplifier transfer function posed the challenge to design and construct real amplifiers that would function closely to this ideal, and hopefully be capable of bringing joy and rapture to the music lover. The result was satisfying, and stimulated a desire to continue with further development.

Building the Real-World Ideal Amplifier

During the experimental process that supported the discovery of the ideal amplifier, various prototype circuits of very advanced innovative design were extensively listened to, using a speaker of unique advanced design. This work largely enabled the definition of the circuitry and components of a pair of monoblock amplifiers. Construction of those amplifiers began in October of 1998, and completion came in April of 1999, with about 1000 hours of highly skilled labour needed. This may be compared with much shorted build times for commercially available amplifiers. A high degree of success was obtained in getting the actual amplifiers to perform very closely to the theoretical ideal. This could only be made possible by drawing heavily upon a lifetime of experience in designing and building vacuum tube amplifiers, combined with a number of subtle serendipitous twists.

Tweaking the Amplifiers

During the final phases of construction of these amplifiers, numerous listening and reliability tests were performed and various components were individually adjusted within each amplifier to obtain the optimum in sound quality from that amplifier. About 50 hours working time went into the tweaking of each amplifier.

Evaluation of Sonic Performance

The sonic performance proved to be most satisfying, providing practical correlation with the theoretically ideal amplifier. The acoustic dynamic range is very satisfying, with lifelike impact, combined with superlative transparency found even in peaks in program material. Most of the listening tests were sourced by audiophile LP pressings of classical and jazz recordings of the highest quality. Transparency was superb in all frequency ranges from the lows to the highs. Transparency remains extremely good even in very soft passages in the music. The quality and timbre of acoustic instruments is exceptional, and remains constant over the range of dynamic levels. A number of experienced local audiophiles heard this system and the findings are that the sonic performance is satisfing, and that the dyanamic range suffers little compression.

True Works of Art

A true work of art has a number of qualities: it is unique, usually hand-made to the highest achievable quality, and most importantly, reflects some aspect of reality. If amplifiers are capable of closely reproducing musical reality, they qualify as true works of art, and are in a class that is beyond the scope of high-end audio.

Investing in Works of Art

It is almost universal in high-end audio that equipment values depreciate in time. However, the case is very different for works of art, which appreciate over time.

Transparency of Amplifiers

Diamonds are priced according to clarity and weight, these corresponding to quality and quantity. A close examination of the prices of the finest high-end audio amplifiers reveals a similar pricing scheme, where clarity becomes the naturalness of the sound and weight becomes the output power of the amplifier, at which the level of transparency is present.

The value of audio amplifiers depends on the build quality, the artistic merit of the physical unit as sculpture, and most importantly upon the sound quality.

Prototype Amplifiers

The amplifiers, pictured on this website, are advanced design amplifiers. These amplifiers were developed in accordance with the ideal output stage characteristic, as espoused in fundamental physics. They have been auditioned using a compatible speaker system of innovative design. The result of recognizing well-established rules of physics is that the listener experiences some of the beauty of music played live.

Invitation to experience a high performance amplifier

I live in Victoria, B.C., Canada, which is located at the southern tip of Vancouver Island, on the west coast of Canada. My telephone number is 1-250-386-1048. I may also be contacted via email at lankford at shaw dot ca.

Copyright 2011 Duncan Scobie. All rights reserved.

rainbowline

The Spiritual Path
& Reproduction of
Beautiful Music
Personal
History of
Duncan Scobie
Improved
Amplifiers
Technical Discussion
of Amplifier Design
Other Audio
Design Projects

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Truth in Audio
Duncan Scobie
1156 Union Road, Victoria, BC, V8P 2J3, Canada
E-Mail: lankford@shaw.ca
URL: www.crunchers.bc.ca/scobie

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