Yamaha AN1x, produced by Yamaha Corporation in 1997, is an analog physical modeling synthesizer, digitally modeling analog sound. It is part of the wave of analog-digital synths using DSP modeling of analog waveforms to recreate the sounds of an analog synthesizer with modern digital specifications. The AN1x employs a mathematical model of how analogue synthesis works to produce sounds. Such digital analog synths do not however reproduce some of the analog synth quirks, such as going out of tune at the top of the keyboard, losing one voice from the polyphony occasionally, and staying on pitch only while the external temperature is constant.

Although the AN1x is not a follow-up to the Yamaha CS1x, it has borrowed an almost identical case with the same layout of buttons and knobs as the CS1x, which is often compared to the Clavia Nord Lead. The AN1x also has a better developed, full 61-note pressure sensitive keyboard.

The AN1x has 10-note polyphony, a twin oscillator, multi-mode filter design with separate pitch, filter and amplitude envelopes, as well as two LFOs. It has an authentic warmth, smooth Pulse Width Modulation (PWM), as well as filters that whistle if the resonance is set too high, and go into oscillation smoothly and predictably, just as with an analog synthesizer.

The AN1x has been used by several artists, including Felix da Housecat, Nitin Sawnhey and Phish.