Threshold Audio

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Threshold Audio is a high-end audio equipment manufacturer originally established in California in 1974 by audio engineer Nelson Pass and graphic designer Rene Besne. The company, today based in Houston Texas, manufactures mono-block and stereo power amplifiers, multi-channel power amplifiers and stereo control amplifiers.

California State of the United States of America

California is a state in the Pacific Region of the United States. With 39.6 million residents, California is the most populous U.S. state and the third-largest by area. The state capital is Sacramento. The Greater Los Angeles Area and the San Francisco Bay Area are the nation's second- and fifth-most populous urban regions, with 18.7 million and 9.7 million residents respectively. Los Angeles is California's most populous city, and the country's second-most populous, after New York City. California also has the nation's most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The City and County of San Francisco is both the country's second-most densely populated major city after New York City and the fifth-most densely populated county, behind only four of the five New York City boroughs.

Nelson Pass is a designer of audio amplifiers. Pass is vocal that listening tests remain valuable and that electrical measurements alone do not fully characterize the sound of an amplifier. Pass holds at least seven U.S. patents related to audio circuits.

Houston City in Texas, United States

Houston is the most populous city in the U.S. state of Texas, fourth most populous city in the United States, as well as the sixth most populous in North America, with an estimated 2018 population of 2,325,502. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the seat of Harris County and the principal city of the Greater Houston metropolitan area, which is the fifth most populous metropolitan statistical area in the United States and the second most populous in Texas after the Dallas-Fort Worth metroplex, with a population of 6,997,384 in 2018.


Nelson Pass and the founding of Threshold

In the early 1970s, Nelson Pass was studying Physics at the University of California-Davis. While a student, he founded PMA to design and manufacture speakers. In 1972, he joined ESS speakers in Sacramento just prior to the arrival of Oscar Heil, who would design the Heil Air Motion Transformer which was a key component of the ESS AMT series of speakers. Pass worked at ESS designing crossovers and enclosures through 1973. He also was a service manager for Sun Stereo performing repairs on McIntosh Laboratory, Phase Linear, Pioneer Corporation and other brands of amplifiers, and began formulating his own amplifier designs in 1974. [1] Pass received his Bachelor of Science in Physics and with an ESS associate René Besne they together began development of a new amplifier in 1974. Besne worked on the industrial design of the amplifier while Pass worked on the circuit topology and component selection. When they were confident the amplifier was ready to market, Pass and Besne incorporated Threshold as co-founders in Sacramento, California on December 5, 1974. [2]

Physics Study of the fundamental properties of matter and energy

Physics is the natural science that studies matter, its motion and behavior through space and time, and that studies the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

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Phase Linear was an audio equipment manufacturer founded by Bob Carver and Steve Johnston in 1970. While primarily known as a power amplifier company it also produced several innovative preamplifiers, tuners and the Andromeda loudspeaker.

Early Threshold Amplifier Designs

The first amplifier sold by Threshold was the model 800A, introduced in early 1975. This was a Class A 200 watt per channel five-stage amplifier with triple series/triple parallel/triple Darlington output stage with a dynamic bias circuit. [3] During development of the 800A, Pass and Besne met Joe Sammut, who later became a business partner in Threshold. [4] The second amplifier offered some months later was the 400A which featured 100 watts per channel. Threshold also released the NS 10 pre-amplifier in 1977.

The Threshold amplifiers drew the attention of audiophiles and editors at audio equipment magazines. In the late 1970s, Pass further developed his amplifier technology and Threshold began to market the STASIS line of amplifiers. This served as the basis of Threshold’s amplifier line throughout the 1980s. Pass was quoted as saying, “The Stasis 1 was the statement product for what became the popular Stasis product line, which served Threshold for the life of the company.” [5] In another interview, he stated: “The Stasis amplifier certainly stands out as probably the premier example of a simple, creative topology that’s done a very good job and stood the test of time.” [6] Virtually all Threshold amplifiers and pre-amplifiers displayed a luxurious look of "sculptured" brushed aluminum faceplates that were Besne's hallmarks of the entire line in keeping with the components’ substantial price. Some of the equipment was offered in black or clear (silver) anodized finish as well. In 1985, Japanese audio company Nakamichi contacted Threshold to acquire a patent license for the Stasis technology in order to market their own high-end amplifier. Pass conducted the consulting work, and Nakamichi Stasis amplifier was sold successfully for several years. [7]

Nakamichi Corp., Ltd. is a Japanese consumer electronics brand that originated in Japan and gained a name from the 1970s onwards for innovative and high quality audio cassette decks. Nakamichi is a subsidiary of Chinese holding company Nimble Holdings.

The 1990s to the Present

Pass was still chairman of Threshold when the November 1991 issue of Stereophile published their extensive interview with him. In subsequent interviews he stated he left Threshold at the end of 1991 to establish Pass Labs and have more autonomy in his amplifier design. Besne also left the firm. [6] [7] During the early 1990s, new amplifier designs known as the T Series were produced by design engineers Mikael Bladilaius, Mike Jaynes and Wayne Coburn. [8] The company also introduced a small line of more affordable amplifiers marketed under the name Forte. With the advent of Home Theater in the late 1990s, high-end audio companies in general and Threshold in particular struggled to retain its audiophile base of customers. Despite its reputation for building an excellent range of audio equipment, Threshold ceased operations sometime during this period. However, by 2000 new buyers had been found for the rights to the designs, tooling, inventory and the Threshold name. An upgraded range of amplifiers based on the proven Stasis technology were brought to market and successfully reestablished the company, known today as Threshold Audio. [9]

Current Product Line

Today, Threshold Audio is located on Emmott Road in Houston, Texas. The current line of Control Preamplifiers includes the T/Pod with iPod input, the Stasis-R 3.0 Stereo Control Preamplifier, and the Stasis-R 5.0 Stereo Control Preamplifier. Current Power amplifiers include the Stasis 7.0 100w/ch Stereo Amplifier, the Stasis 8.0 200w/ch Stereo Amplifier, the S/3700e Multi-channel Power Amplifier, and the S/7000e MonoBlock Power Amplifier. [10]

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  1. Didden, Jeff. We Interview Nelson Pass. Multi Media Manufacturer, January–February 2010
  2. Norton, Thomas J. Nelson Pass: Simple Sounds Better. Stereophile, November 1991.
  3. Stone, Steven, Nelson Pass Interview. Audiophile Review, May 19, 2011.
  4. Stereophile, 1991
  5. ”Searching for the Extreme: Nelson Pass of Pass Labs.” Ultra Audio Archives, March 2008.
  6. 1 2 Stereophile, November 1991
  7. 1 2 Didden, Jan. “We Interview Nelson Pass.”
  8. Soderberg, Jon. “The Vintage Amplifier Museum.”
  9. Nack, Marshall. “Threshold STASIS 7.0 Amplifier,” The Stereo Times, September 20, 2002.
  10. Threshold Audio website