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An 'analog synthesizer' is a synthesizer that uses analog circuits and analog computer techniques to generate sound electronically.

Contents

Analog synthesizer circuit composition

Pioneer synthesizers

First generation modular synthesizers

First generation all-in-one synthesizers

Second generation all-in-one synthesizers

Third generation all-in-one synthesizers

The fall and rebirth of analog synthesis

External links

Analog synthesizer circuit composition

A very common circuit component in analog synthesizers is the operational amplifier (op-amp), a kind of integrated circuit; most of analog synthesizers contain many of them; earlier models were built using transistors instead of microchips. Another common component is a potentiometer (pot, or variable resistor), which is used to adjust the traits of the sound that is produced.
Some common components that consist of multiple parts are low-pass filters and high-pass filters.

Pioneer synthesizers

The earliest synthesizers used a variety of valve and electro-mechanical technologies. While some electronic instruments were produced in bulk, such as the Ondioline, the Hammond organ, the Trautonium, many of these would not be considered synthesizers by the standards of later instruments. However, some individual studios and instruments certainly achieved a high level of sophistication and untapped promise, such as the Mixturtrautonium of Oskar Sala, the Electronium of Raymond Scott, and the ANS synthesizer of Evgeny Murzin.

First generation modular synthesizers

Early analog synthesizers used technology derived from electronic analog computers and laboratory test equipment. They were generally "modular" synthesizers, consisting of a number of independent electronic modules connected by patch cables.
Synthesizer modules found in early analog synthesizers included:

★ voltage-controlled oscillators

★ voltage-controlled filters

★ voltage-controlled amplifiers

★ envelope generators

★ low-frequency oscillators

★ ring modulators

★ reverb units

★ sequencers

★ sound mixers
Because many of these modules took input sound signals and processed them, an analog synthesizer could be used both as a sound-generating and sound-processing system.
Famous modular synthesizer manufacturers included Buchla & Associates,
Moog Music, ARP Instruments, Inc., and Electronic Music Studios.
Moog established world wide recognized standards for analog synthesizer control interfacing, using a logarithmic 1-volt-per-octave pitch control and a separate pulse triggering signal. These control signals were routed using the same types of connectors and cables that were used for routing the synthesized sound signals.
A very specialized form of analog synthesizer was the analog vocoder, based on equipment developed for speech synthesis. Vocoders could be used to make a sound that resembled a musical instrument talking or singing.

First generation all-in-one synthesizers

Later analog synthesizers used the same building blocks, but integrated them in a single unit, eliminating the patch cords in favour of an integrated signal routing system. The most popular of these was the Minimoog.
Famous makers of all-in-one analog synthesizers included Moog, Arp, Roland, Korg and Yamaha. Because of the complexity of generating even a single note using analog synthesis, most synthesizers remained monophonic.

Second generation all-in-one synthesizers

A second generation of analog synthesizers emerged later, with limited polyphony, typically supporting four voices. Oberheim was a notable manufacturer of analog polyphonic synthesizers.
The Polymoog was an attempt to create a truly polyphonic analog synthesizer, with sound generation circuitry for every key on the keyboard. However, its architecture resembled an electronic organ more than a traditional analog synthesizer, and the Polymoog was not widely imitated.

Third generation all-in-one synthesizers

In 1978, the first microprocessor-controlled analog synthesizers were created by Sequential Circuits. These used microprocessors for system control and control voltage generation, including envelope generation, but the main sound generating path remained analog. The MIDI interface standard was developed for these systems. This generation of synthesizers often featured six or eight voice polyphony. Also during this period, a number of analog/digital hybrid synthesizers were introduced, which replaced certain sound-producing functions with digital equivalents, for example the digital oscillators in synthesizers like the Korg DW-8000 (which played back PCM samples of various waveforms) and the Kawai K3 (waveforms constructed via additive synthesis).
With the falling cost of microprocessors, this architecture became the standard architecture for high-end analog synthesizers.

The fall and rebirth of analog synthesis

Analog synthesizers were mostly replaced by digital synthesizers and samplers over the early-mid 1980s. In the mid 1990s a fashion emerged for "retro" analog synthesizers with their proponents claiming that the "analog sound" of old analog synthesizers could not be accurately replicated using samplers or digital synthesizers. This led to increased demand for used analogs (such as the Roland TR-808 drum machine and Roland TB-303 bass synthesizer) the construction of a new generation of analog synthesizers (including modern-day modular synthesizers) and the development of a variety of analog modeling synthesizers which emulate analog VCOs and VCFs using samples, software, or specialized digital circuitry.
The lapse of patents in recent years, such as for the Moog synthesizer transistor ladder filter, has led to a small resurgence in DIY or kit synthesizer modules, as well as an increase in the number of commercial companies selling analog modules. Reverse engineering has also revealed the secrets of some synthesizer components, such as those from ARP Instruments, Inc, which were potted in epoxy cases to prevent inspections.

External links

★ ARP synthesizer patents

★ Modular Analog Synthesizers Return! - a discussion of modern modular equipment with links to major manufacturers.