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Electronics Designer Roundtable

Electronics Designer Roundtable

Kazutoshi Yamada Zanden Audio System Company, Limited

Electronics Designer Roundtable

I studied electrical and electronic engineering at Osaka Prefecture University to understand the finest nuances of amplifier operation. Since founding Zanden Audio in 1980, I have devoted more than thirty years to perfecting amplifier design. During this time, I have not only worked on the technology but have also participated in live performances as an “audio coordinator.”

Through my involvement in over 500 concerts, I have observed first-hand the very wide gap between the sound of live music and its reproduction. This gap causes a disconcerting feeling of disconnection from the live event. Many listeners who love and enjoy music have experienced the same phenomenon, and shared their perceptions. This led me to realize that, as an audio engineer, I had a duty, even a sacred mission, to close the gap between the sound of a live performance and its reproduction.

What musical qualities were you striving for in the 8120 and 3100?
One of the areas where all of our amplifiers excel is the energy balance between the fundamental and overtones. Getting this balance correct is key to reproducing accurate low-level detail. The timbre is more realistic, allowing the listener to not only easily discern the type of instrument, but also to hear the subtle differences between instruments of the same type. Massed strings sound like individual instruments playing together (rather than a homogenous sound). Music is layered and textured with a lifelike, three-dimensional character.

The 8120 and 3100 are some of your most affordable products. How has your experience in designing flagship-level products informed your approach to creating the 8120 and 3100?
Our work designing such products informs everything we do. Although making our products more widely available is a primary goal, every product must uphold Zanden standards of quality and musicality. We know what sounds good and what does not. Where we can reduce material costs while maintaining Zanden performance, we do so. If we cannot, we will not.

Both the model 3100 and model 8120 are excellent examples of this product philosophy. They share the same basic architecture as their more illustrious siblings. The primary differences with our flagship-level offerings are the cost of materials. Although the cost of the model 3100 and 8120 is significantly less than our flagship models, the effect on performance is minute.

You’ve chosen to work with tubed circuits. What do you see as the advantages of tubes?
By their very nature tubes are more linear than solid-state devices and allow for relatively simple circuits. Solid-state amplifiers, on the other hand, require greater complexity. As a general rule, the more complex a circuit becomes, the more difficult it is to achieve ideal results. Additionally, tube circuits can be constructed without using any negative feedback at all, or in the case of our model 8120 with minimal amounts.

This is not to say that I will never design solid-state components, and it would be a mistake for people to regard Zanden simply as a tube equipment manufacturer. I have already designed a solid-state phonostage, our model 120. Our circuits contain few traditional elements, and many aspects of our tube designs are applicable to solid-state amplifiers. In addition, the judicious use of solid-state components allows us to reduce the cost of our equipment with minimal reductions in performance.

How much of the design process is based on measurement and how much on listening? Is there a correlation between an amplifier’s technical performance and its musical qualities?
Measurements are not central to my design process because they cannot account for the listening experience. Observation is our best tool for evaluating circuit designs. If I were to rely on theory alone, I would never have designed tube amplifiers, and especially not single-ended tube amplifiers. Yet many of my earliest amplifier designs were single-ended tube amplifiers. Neither measurements nor theory can explain why SET amplifiers often sound so much better than other designs. Experience contradicts theory and measurements. This gap between theory and observation was one of the primary inspirations for our push-pull amplifiers.

By technical performance I infer that you mean measured performance. Assuming that a product is generally well designed, there is very little correlation between measured performance and musical qualities. Measurements are counterproductive in that they create artificial goals with minimal correlation to observed performance. Measurements are useful for checking the technical soundness of a circuit. They can reveal problems that have been overlooked, mistakes, or unexpected behaviors. Measurements can tell you when something is wrong, but they cannot tell you when something is right.

How much better will amplifiers get over the next ten years? Are you still learning new things?
The pace of progress in the analog world is normally much slower than in the digital one. Our current knowledge base is quite limited and so many areas remain veiled by uncertainty and ignorance. In general, I see the influence of high-frequency noise to be one largely unknown factor that is detrimental to the performance of audio components and the musical experience associated with the playback of recorded music. Without the allocation of large financial resources to basic science and research, the chances of a technological revolution in audio are unlikely. I would expect improvements to continue at the current slow pace, which is characterized more by evolutionary advances rather than revolutionary ones.

Each amplifier technology has weaknesses, and that is where we can find room for the greatest improvement. The filtering techniques used for reducing the audible effects of sampling noise in digital amplifiers are currently inadequate. Solid-state amplifiers require improvement in their power-rectification sections. In order to improve tube amplifiers further, we need a revolutionary advancement in output transformer manufacturing. Lastly, I believe that both solid-state and tube amplifiers would benefit from a review of feedback technology.

Of course I am still learning. Advances do not happen in a vacuum. If you had asked me ten years ago whether Zanden would have made the advances in amplifier technology that we have achieved, I would have said “no.” At the time, other challenges such as the unaccounted effects of digital low-pass filters on digital playback loomed large. In the process of solving one problem you learn new things, and sometimes they have applications in other areas. Also, advances by manufacturers in other fields, such as speaker and cartridge design, reveal new insights.

 

George Counnas Zesto Audio

Electronics Designer Roundtable

Started four years ago, Zesto Audio is a relatively new company. In reality it took the experience of forty years to become what seems like an overnight success. George feels lucky that as a young man in England, he first learned tube circuitry in college before the technology switched to transistors. He worked in R&D for Decca England (now Raytheon), which gave him the invaluable experience of designing, testing, and bringing a quality product through full production. George’s love of music and engineering skills led to a career as an audio engineer, where he spent tens of thousands of hours in the studio doing critical listening. Zesto Audio was born from a desire to bring that accuracy to high-end audio. George realized that the power amp was the key to achieving that level of accuracy, as it allows all the components in your system to live up to their potential.

What musical qualities were you striving for in the Bia 120?
It’s all about balance. It’s having all the sonic elements in the right proportion. I wanted the amp to sound alive, dynamic, and open, but at the same time non-fatiguing. As an audio engineer, I wanted to hear the instruments, not the equipment. For that to happen, the amp would need to reproduce music in the most transparent way possible, with fast attacks and neutral-sounding mids and highs. I wanted to be able to hear the subtle difference of a dry saxophone reed as opposed to a very wet one. The amp design should not only reproduce the instruments accurately, but also the space around them. I wanted to get a sense of the soundstage and the room the musician performed in—is it a concert hall or a vocal booth?

You launched Zesto Audio with a phonostage, and then introduced a linestage, and now a power amplifier. Did the phonostage and linestage design inform your approach to the power amplifier?
I’m glad I started upstream with the phonostage and linestage because it gave me a much better understanding of the job in store for the Bia 120. Power amps have a disproportional influence on the overall sound of your system because you are asking them to take in a very small signal and blast it out powerfully through the speakers, but with great detail and delicacy. Knowing intimately the full potential of my other products helped keep my design decisions on track.

It was important to maintain the Zesto philosophy of using the fewest number of components—not for cost savings, but because there’s less noise, less distortion, and fewer chances of interference in the signal path. Some of the design elements carried over from the first two products are the industrial design, the use of true transformer floating balanced inputs, the use of ground-loop switches to isolate noise from the other components, and all-tube circuitry with no solid-state anywhere in the signal path.

You’ve decided to work exclusively with tubed circuits. What do you see as the advantages of tubes?
Tubes create even-order harmonics, which produce a warmer, more pleasing sound. What most people don’t know is tubes can actually be faster than solid-state devices, and this is especially true in a Class A power amp. What I like most about tube circuits is that they are inherently simple but also precise, and therefore use the fewest number of parts. My experience at Decca trained me to deal with the high voltages in tube circuits, which was particularly helpful when designing the power amp. I start with tubes because in the end they always provide the sound I am striving for.

How much of the design process is based on measurement and how much on listening?
I think it’s equal. Every sonic adjustment I make is measured and listened to. Every decision can be a compromise; sometimes you compromise technical performance for sonic benefits and sometimes you make adjustments for technical benefits.

I start the design process with purely technical measurements. Of course, the product’s unlistenable at that point, but it must be a stable-performing unit before I can make any sonic adjustments. On the Bia 120, those adjustments included over 68 circuit revisions, hundreds of component changes, and daily listening. The final design has to meet basic technical specifications. At the same time the unit has to sound good. If there is a choice between a “perfect” tech spec and better sound, I would choose a better sound. In other words, I don’t listen to specs, sinewaves, or test tones—I listen to music.

Is there a correlation between an amplifier’s technical performance and its musical qualities?
I see no correlation. Line up ten power amps with the same specs and tell me how they will sound in your system?

How much better will amplifiers get over the next ten years? Are you still learning new things?
I’m still learning and perfecting 1930s technology, but I get to do it with computer-aided design.

Unless there is a new amplification technology on the horizon, I think engineers will continue to find better ways to refine the current technologies.

 

Paul Jayson Viola Audio Laboratories

Electronics Designer Roundtable

Paul’s enthusiasm for music began naturally as a teenager. He simply loved music. Paul became a Pro Audio Sound engineer for area bands. When he invested in the Mark Levinson JC2 preamplifier for his home, his world changed forever: he was so enamored with the performance and design of the JC2 that any other career options were dashed. He had to design high-end audio.

Paul joined Mark Levinson’s Chief Engineer Tom Colangelo in 1980. Paul earned his BSEE from the University of Hartford during this period. In 1984 Mark Levinson formed Cello, and Tom Colangelo and Paul Jayson joined him. For more than 30 years, Tom Colangelo and Paul Jayson perfected their craftsman approach to the design of high-end amplifiers and preamplifiers. When Cello ceased operations in 2000, Tom and Paul formed Viola Audio Laboratories. The result? A high-performance audiophile product line based on years of design that has become one of the most respected in the industry.

What musical qualities were you striving for in the Crescendo and Concerto?
For all products in our line we strive for simplicity—simplicity in musical reproduction as well as in function. Of course, when all is said and done, it’s the music that matters. Magic happens when a recording is reproduced with all of the nuance of the original recording session. My passion is music created as an art form by an artist, and the art of live music performance. I want to be as close to the moment it was created as possible. The path of delivery should be a direct one. Nothing added in between. Just a simple, clean, honest conveyance of the music within the soundstage as it was meant to be heard.

A lot of people tell me the sound of Viola Audio Laboratories is musical. Now, what that means is as varied as the individual listening; for me, it’s achieving a sense of belonging, if you will. It’s a connection between my senses and what I’m hearing, an emotional, engaging experience. It’s that experience we strive for in all product development.

The Crescendo and Concerto are some of your most affordable products. How has your experience in designing flagship-level products informed your approach to creating the Crescendo and Concerto?
I must say simplicity was the design foundation for the Crescendo preamplifier and the Concerto power amplifier. Flagship products always provide a point of reference for new product design. All Viola Audio Laboratories products come from this same design philosophy and share much of the same technology as our flagships. For example, the Concerto power amplifier incorporates a choke input power supply. While the Crescendo and Concerto owe much of the design philosophy to the flagship products, the inspiration to develop them came from our desire to create new products utilizing new circuit topologies. They also incorporate present technology for the user interface using Wi-Fi applications for devices such as the Apple iPad or iPhone.

You’ve decided to work exclusively with solid-state circuits. What do you see as the advantages of transistors over tubes?
I’ve been working in the solid-state domain since 1980. I understand the appreciation for both the tube and solid-state approach, but I believe it’s important to do what you do best. I’ve found great success with solid-state design over the years, and our product line reflects the best of what can be achieved.

How much of the design process is based on measurement and how much on listening? Is there a correlation between an amplifier’s technical performance and its musical qualities?
No question about it, my approach is based on measurement. If I had to quantify it, I’d say about 90% measurement. It is an electronic piece of equipment, and therefore must adhere to the laws of physics and sound electrical-engineering design principles. There are so many parameters to consider when designing power amplifiers. Whether I’m designing for damping factors, feedback margins, etc., measurement must be considered.

However, listening is critical, too, because the most honest musical reproduction is what I want to achieve. My thirty-plus years of experience certainly has provided me with a sense of which parameters work well together as far as sound goes. That’s really what’s most important. But how you get there must be based on the performance of each component and their relationship as a whole. It’s a complex process, and I consider the realities of physics as well as how each parameter works with each other.

How much better will amplifiers get over the next ten years? Are you still learning new things?
No doubt progress will continue far into the future for electronic reproduction systems in general. As a designer, I depend on the devices that are available. Capacitors, output transistors, and everything in between have evolved over the years to one degree or another. A good example of this is found in the Concerto power amplifier where I use ThermalTrak transistors, which were only introduced a few years ago.

This is a passion of mine and I have fun doing it. My goal is to design the best possible components for the most discriminating lover of music, and I’m always learning through experimentation. My philosophies haven’t changed. But as new tools become available, it is exciting to see how they will improve our product line.

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