ARP Explorer I (1974–1978)

Name: ARP Explorer I
Brand: ARP

Monophonic analog synthesizer with programmable presets and a classic ARP filter, made in the USA.

Overview

The ARP Explorer I (Model 2900) is a programmable preset analog synthesizer produced by ARP from 1974 to 1978. It was ARP’s first non-preset single oscillator synthesizer and marked a transition from fixed presets to user-programmable sounds in ARP’s compact synth line. The Explorer I is monophonic, making it ideal for basslines and lead melodies, and features a 37-key full-size synth-action keyboard. Known for its rich, resonant analog tone, it has been used by notable musicians including Philip Glass and Herbie Hancock.

Specifications

Model Number	2900
Polyphony	Monophonic
Oscillators	1 VCO with sawtooth, square, narrow pulse, modulated-width pulse waveforms and Pink Noise generator
Filter	4-pole (24dB/oct) low pass filter with cutoff and resonance controls
LFO	1 LFO with adjustable speed, depth and delay controls
Envelope	1 ADSR envelope (VCA)
Keyboard	37 keys, Synth Action, Full Size
Effects	Repeat, delayed vibrato, bender, portamento, pitchbend
Finish	Black / Gold
Manufacturing Origin	United States

Design

The ARP Explorer I uses the same 4027-1 Voltage Controlled Oscillator module as the ARP 2600 and the 4034 Moog Ladder Filter Voltage Controlled Filter module found in the ARP Pro Soloist. Its analog architecture provides a characterful, expressive sound, with a waveform section that allows mixing of various waveforms at different pitch ranges. The VCF/VCA section includes basic ADSR and filter controls, while the effects section features dedicated controls for repeat, vibrato, pitch bend, and portamento.

Context

The Explorer I was very similar to ARP's Pro-Soloist and Pro-DGX preset synths and pre-dated the Axxe and Solus. It represented ARP’s shift from preset-based compact synths to programmable models, offering greater user control over sound creation.

Market

The ARP Explorer I is a rare and unique piece of equipment, with a current market price of $1,520.27 for used units as of April 1, 2026. Aftermarket slider kits and parts are available from retailers such as Synth Patchers.

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