It is a common misperception that a standard IC opamp is a single active device. In fact we sometimes get comments such as “less is more!, so why not just use an IC opamp on your circuitry, just like so many other audio companies?”
We agree that less is more, it is precisely why we can never accept IC opamps. Each IC opamp is densely packed with over 50 micro components and audio signals travelling through them. These micro components are chemically formed and inferior in every way to even the cheapest of discrete components. (see below for more) Furthermore, even Wikipedia knows that IC opamps were created for the PC industry, and were designed to work in a vast range of equipment and temperatures. To achieve such versatility, the tiny circuitry inside the opamp contains many components and corrective networks that are useless to audio amplification. As a result, audio signals travelling through them are tainted beyond repair.
We sit squarely in the less is more camp. In the first generation HA-160 input stage we were able to achieve ideal operational levels with 32 carefully selected and matched discrete components. By reducing the number of components on the signal path, more micro details were able to get through. The result is a higher definition and more organic sound compared to any IC chip based design.
During the development of the Soloist, one of our theories was confirmed. That even the best discrete and most matched components introduce distortion when used on the signal path. But, every time a component is removed from the signal path, a veil is lifted between us and the music. The design objective therefore was to remove as many components from the signal path as possible while still maintaining ideal operational levels.
At the end, we developed a brand new Field Effect Transistor (EFT) circuit for the Soloist. It has only 21 components on the signal path. It was an absolute breakthrough for us, and the result was breathtaking.
There is a common misconception among audiophiles: That is an Integrated Operational Amplifier (IC Opamp) is equivalent or even superior to a discrete design. Nothing can be further from the truth! Restricted by the fabrication process and technological limitation an IC Opamp is an inferior substitute for a proper discrete design. An IC Opamp is entirely constructed on a single dice of silicon waver, which is smaller than a grain of rice. Limited by its size and heat dispersion, it is impossible to incorporate a top quality audio transistor like the A970, or K170 which feature in the Burson Audio discrete design. During the construction of a discrete transistor a chemical optimisation process take place for each pieces of silicon according to there application (NPN or PNP). This optimisation process is critical to the performance of the final product. Some of the benefit included:
optimized for breakdown voltage and performance
optimized for near-true complementary
But this process can not take place on an intergraded circuit since all transistors is fabricated on the same piece of silicon. This is one of the major drawn back of an intergraded circuit compare to a discrete circuit.
All components on the silicone dice are formed by droplet of chemical (very much like inkjet printer printing on paper). This fabrication process can not create parts like the 1% tolerant metal film resistor, or the super stable silver mica capacitor (please see table above to compare how discrete parts are different to their intergraded substitute) Since they are all connected (hence integrated) they can not be individually tested and matched.
In an IC opamp the conductor layer that connects all the parts is formed by a layer of aluminium vapour that is thinner than the water vapour left on foggy windscreen. This poor conductor is the silent killer to musical texture.
The close proximity of components also poses a problem for audio signals, where that delicate signal that music lovers pursue, will be masked by EMI noise.
In the end, the consumer is getting an opamp that is built with a bunch of second grade parts that is unable to yield the best results, connected via a thin layer of aluminium foil.
An IC opamp is nothing more than a cost cutting substitute in audio application which we hate with a passion!
To learn more about the fabrication process of Intergraded Circuits please visit the following links:
“How Can We Create an Integrated Circuit from Sand?” Exploration 1B: Comparing Macroscopic and Microscopic Circuit Components by Melonie A. Teichert, Angelica M. Stacy, Alice C. Rico, Susan E. Kegley, Jennifer G. Loeser, Marco Molinaro, and Susan E. Walden. Applets programming by Cora Estrada and Toshiro Horie.Circuit images by Marco Molinaro, Susan Walden and Sue Whitmore.
(http://chemistry.beloit.edu/Chip/pages/macromic.html) “The History of the Integrated Circuit”
by Nobelprize .org (http://nobelprize.org/educational_games/physics/integrated_circuit/history/)
Reference: “Plasmas and Plasma-Surface Interactions” by Dr Paul May , University of
Bristol, Bristol BS8 1TS, UK “Integrated circuits” by Integrated Publishing, USA “Integrated circuit” Wikipedia, The free encyclopedia