Origins and Development
The Waldorf Microwave emerged from the ashes of Palm Products Germany (PPG), the pioneering synthesizer company founded by Wolfgang Palm that had created the legendary PPG Wave series. When PPG ceased operations in 1987, Waldorf Electronics GmbH was founded in 1988 in Waldorf, Germany by Wolfgang Düren, who had been the German distributor for PPG. The company's mission was clear: to continue the development of wavetable synthesis that PPG had pioneered.
The Microwave was Waldorf's first product, released in 1989. It represented a unique hybrid approach to synthesizer design, combining digital wavetable oscillators with analog filters—a sonic architecture that would become Waldorf's signature. At the heart of the Microwave was a custom-designed Application-Specific Integrated Circuit (ASIC) developed in collaboration with none other than Wolfgang Palm himself, the inventor of wavetable synthesis. This chip, combined with a Motorola MC68000 microprocessor running at 250 kHz internal sampling rate, formed the digital backbone of the instrument.
Design Philosophy and Architecture
The Microwave's design philosophy centered on what Waldorf called "Dynamic Spectral Wavetable Synthesis" (DSWS). Unlike traditional subtractive synthesis that uses static waveforms, wavetable synthesis allows for real-time scanning through series of related waveforms, creating evolving timbres that could shift dramatically over time. The Microwave contained 32 wavetables, each with 64 waves, most derived from the original PPG Wave 2.2 and 2.3 synthesizers but reorganized and expanded with additional wavetables.
Each voice featured two digital oscillators that could access these wavetables, with the crucial addition of analog filters to warm the digital sound. Early Microwave units (Revision A) used Curtis CEM 3389 low-pass filter chips, while later units (Revision B) used CEM 3387 chips. This analog filter stage was critical to the Microwave's character, providing the warmth and punch that pure digital synthesizers of the era often lacked.
The instrument offered 8-voice polyphony, expandable to 16 voices with the optional Microwave Waveslave expansion module. It featured four envelopes (amplitude, filter, 8-stage wavetable with looping capabilities, and LFO), two LFOs with multiple waveforms and "humanize" parameters, and a 24-source modulation matrix that allowed for complex sound design. The Microwave was also 7-part multitimbral, making it suitable for complex studio arrangements.
Hardware Revisions and Variants
The original Microwave underwent several hardware revisions during its production run. The most significant difference was in the display: early models featured a backlit LCD, while later models used a lit character display. The filter chips also changed between revisions, with the CEM 3389 in early units giving way to the CEM 3387 in later production.
In 1994, Waldorf released the "Mean Green Machine"—a limited edition Microwave with a distinctive green "Nextel" rubberized finish, certificate of authenticity, special cone-shaped metal feet, and playful silkscreening (the power switch was labeled "Life" and the card slot "Food"). This was released alongside the Version 2.0 operating system upgrade, which added significant features including additional wavetables, algorithmic wavetable creation tools, and a speech synthesizer. Following this limited edition, standard Microwave units adopted the Nextel finish in the classic blue color that would become a Waldorf trademark.
Impact and Notable Users
The Microwave quickly found favor among professional musicians and producers, becoming a staple sound source for electronic music throughout the 1990s. Its unique character—capable of everything from silky smooth pads to brutally aggressive basses—made it particularly popular in dance music, industrial, and film scoring.
Notable users included Depeche Mode, who employed the Microwave extensively alongside its bigger sibling, the Waldorf Wave. Hans Zimmer used the instrument for film scoring, appreciating its ability to create evolving textures. The Orb incorporated Microwave sounds into their ambient house productions. Other prominent users included Jean-Michel Jarre, Vangelis, Enya, A-ha, Nine Inch Nails, and Björk.
The Microwave's sound became particularly associated with the rising electronic dance music scene of the early 1990s. Its ability to produce massive, punchy bass lines and evolving, enigmatic wavetable modulations made it ideal for techno, trance, and ambient productions. The instrument's "brutal attacks, snappy decays, and plethora of wonderful transients" (as described in Waldorf's own marketing) gave it a sonic presence that cut through mixes with authority.
Production History and Legacy
The original Microwave remained in production from 1989 until 1997, when it was superseded by the Microwave II. The Microwave II represented a significant architectural shift, replacing the analog filters and custom ASIC with a Motorola DSP-driven design, resulting in a different sonic character. The original Microwave (retroactively designated Microwave I) maintained a devoted following among purists who prized its unique analog filter sound.
Approximately 4,000 units of the original Microwave were produced during its eight-year production run. The instrument's influence extended far beyond its sales numbers, establishing Waldorf as a serious synthesizer manufacturer and proving that hybrid digital/analog architectures could offer the best of both worlds: the complex evolving timbres of digital wavetable synthesis combined with the warmth and character of analog filters.
Today, the original Microwave is highly sought after on the used market, commanding premium prices due to its unique sound and relative scarcity. In 2026, Waldorf released the Microwave 1 Plugin—a software recreation that painstakingly models the original hardware, including the custom ASIC, Curtis filter chips, and even the non-linearities of the original digital-to-analog converters. This plugin can even control original hardware units, serving as both a software instrument and a sophisticated editor for those lucky enough to own the vintage hardware.
The Microwave's legacy lives on in Waldorf's current product line, with the 2022 Waldorf M synthesizer explicitly designed to recreate both the Classic Microwave I and Modern Microwave II/XT sound characters. The wavetable synthesis concept pioneered in the Microwave and PPG Wave remains a cornerstone of modern synthesizer design, influencing instruments from Native Instruments' Massive to Ableton's Wavetable and countless hardware and software synthesizers. The Microwave stands as a testament to the vision of its creators and the enduring appeal of hybrid synthesis architectures.