Origins and Development
The Waldorf Microwave XTk emerged from a lineage of wavetable synthesis that began with PPG (Palm Products Germany) in the early 1980s. After PPG ceased operations in 1987, Waldorf Electronics GmbH—founded in 1988 by Wolfgang Düren, the former German distributor for PPG—carried forward the legacy of wavetable synthesis. The company name references Waldorf, a town near Bonn, Germany, where the company was established.
Waldorf's first major release was the Microwave I in 1989, which brought wavetable synthesis to a wider audience at a more accessible price point than the legendary PPG Wave. However, the original Microwave's minimal interface—a single-knob design with extensive menu diving—frustrated many users who wanted more immediate control over the powerful synthesis engine.
The XT Revolution
The Microwave II followed in 1997, featuring a DSP-driven architecture and an improved user interface. But it was the Microwave XT, released in 1998, that truly addressed user demands for hands-on control. With its striking bright orange panel and 44 dedicated rotary knobs, the XT transformed the synthesizer from a studio rack unit into a performer's instrument.
In 1999, Waldorf released the XTk—the keyboard version that combined the XT's synthesis engine with a four-octave keyboard. The XTk retained all the XT's capabilities while adding 49 full-size velocity-sensitive keys with channel aftertouch, pitch and modulation wheels, and the same knob-laden interface that made the XT so popular. The Sound On Sound review from March 2000 praised it as "the first affordable wavetable synth with a built-in keyboard."
Design Philosophy
The XTk embodied Waldorf's commitment to powerful digital synthesis with analog-style control. The 44 rotaries controlled nearly every immediate function, making real-time sound manipulation intuitive and immediate. The distinctive orange finish and wooden end cheeks gave it a unique visual presence that stood out in any studio or stage setup.
Under the hood, the XTk was a fully digital synthesizer using Motorola DSP technology. It combined wavetable synthesis—scanning through series of digitally stored waveforms—with FM synthesis, ring modulation, and noise generation. Unlike the original Microwave I, which used analog Curtis filters, the XTk employed sophisticated digital filters with 13 different modes including 24dB and 12dB low-pass, waveshaper, FM filter, and dual parallel configurations.
Notable Users and Legacy
The Microwave series, including the XTk, found favor with electronic musicians seeking distinctive digital textures. While specific XTk users are less documented than those of the flagship Wave synthesizer, the Microwave line in general was embraced by artists exploring the intersection of digital precision and analog-like warmth.
Waldorf's instruments were favored by prominent electronic artists including Jean-Michel Jarre, Depeche Mode, Hans Zimmer, The Orb, and Nine Inch Nails. The XTk's combination of wavetable synthesis and hands-on control made it particularly appealing for live performance and sound design applications.
Production History and Demise
The XTk was manufactured from 1999 until Waldorf's bankruptcy in February 2004. When the original Waldorf AG declared insolvency, production of the Microwave II, XT, and XTk models ceased. A new company, Waldorf Music GmbH, was established in 2006 but chose not to resume Microwave production, instead focusing on the Blofeld synthesizer as their flagship wavetable instrument.
The XTk's legacy lives on in software emulations and the continued popularity of the Microwave XT among vintage synthesizer enthusiasts. The instrument's distinctive orange color and knob-heavy interface have made it a sought-after collector's item, with prices on the used market often exceeding original retail values. The design philosophy of powerful digital synthesis with extensive hands-on control continues to influence Waldorf's current product line, including the Quantum and Iridium synthesizers.