Sunday, May 21, 09:00 — 11:30
Jamie Angus (Chair)
P10-01 Supply Voltage Scaling Technique of Triode Tube Based on Harmonic Distortion Characteristics
Kanako Takemoto (Presenting Author), Toshihiko Hamasaki (Author), Shiori Oshimo (Author)
In recent years, applying a triode tube to the guitar pedal as a signal modulator has been attracting considerable attention. The miniature tube 12AX7/ECC83 is still the key component for creating main sound properties of a guitar amplifier owing to its specific non-linear characteristics. Therefore, the attempts to incorporate the tube harmonic distortion sound to the pedal instead of solid-state circuit came out in the market. This paper describes a technique to generate the same harmonic spectrum focusing tube Crunch sound at 150V power supply voltage, which is half of conventional 300V. This voltage scaling contributes to reducing the battery power consumption of the tube guitar pedal to prolong the playing time.
Convention Paper 9733
P10-02 Linear Phase Crosstalk Cancellation Filters
Arnaud Reymond (Presenting Author), Christof Faller (Author), Daniel Weiss (Author)
The filter design approach presented here manages an attractive compromise that produces filters with good crosstalk cancellation, short impulse responses, and a linear phase. As a starting point, basic cancellation filters are considered, i.e., ideal pulses with delay and inversion. These are modified in the frequency domain with a gain applied so as to obtain a nearly spectrally flat total power at the ears. This modification allows to substantially reduce the coloration of the basic cancellation filters at the price of a small decrease of cancellation performance.
Convention Paper 9734
P10-03 GaN FETs Drive Fidelity and Efficiency in Class-D Audio Amplifiers
Stephen Colino (Presenting Author), Skip Taylor (Author)
With the current maturity of Class-D audio amplifier architectures, amplifier fidelity and efficiency limitations are primarily at the device level. Silicon MOSFETs have been evolving for almost forty years, and their progress towards a perfect switch has slowed dramatically. There are some fundamental characteristics of MOSFETs that degrade sound quality and efficiency. In 2010, the enhancement mode Gallium nitride (GaN) power FET was introduced by Efficient Power Conversion (EPC), providing a large step towards the perfect switch.
Convention Paper 9735
P10-04 Ultra Efficient Linear Amplifiers
Jamie Angus (Presenting Author)
“Class-D” switching amplifiers are considered to be the most efficient amplifiers. However, designers must deal with supply rail, and radio frequency interference, and the need to switch power devices at high frequencies. Because of these, and other problems, not everyone wishes to use switching based technologies amplifiers. Unfortunately, linear amplifiers are significantly more inefficient than switching amplifiers under sine wave testing. However real audio signals spend much more time at low amplitudes than a sine wave. By changing the switch point for “Class-G” or “Class-H” they can have efficiencies that rival “Class-D” amplifiers producing the same output. The paper develops optimum switch points for both single and multiple switching points, with respect to the expected amplitude distribution of the audio.
Convention Paper 9736
P10-05 Evaluation of Audio Performance over Product Life
Wolfgang Klippel (Presenting Author)
Most measurements are performed on audio products during the development of the first prototype and at the end of the production line. Physical measurements and perceptional evaluation in the target application (e.g., car interior) are also required to define the target performance, to finish successfully the development and to evaluate the reliability and robustness of the product under the influence of climate, aging, and other external factors. This paper discusses evaluation techniques that are useful in the different phases of the product life cycle to generate a successful product that provides the maximum benefit to the end user.
Convention Paper 9737