ARP Explorer I (1974–1978)

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. ARP built it from 1974 to 1978. It was ARP's first non-preset single oscillator synth, and it marked the move from fixed presets to user-programmable sounds in the compact line. It is monophonic, so it suits basslines and lead melodies. The keyboard is 37 full-size synth-action keys. The tone is resonant and analog, and Philip Glass and Herbie Hancock are among the musicians who used it.

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 Explorer I uses the same 4027-1 Voltage Controlled Oscillator module as the ARP 2600. The filter is the 4034 Moog Ladder Filter Voltage Controlled Filter module, the same one found in the ARP Pro Soloist. The waveform section lets you mix several waveforms at different pitch ranges. The VCF/VCA section has basic ADSR and filter controls. The effects section has 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 it pre-dated the Axxe and Solus. It was ARP's shift from preset-based compact synths to programmable ones, with more user control over the sound.

Market

Used units currently go for about $1,520.27 as of April 1, 2026. Aftermarket slider kits and parts are available from retailers such as Synth Patchers.

Similar items on eBay

No exact ARP Explorer I listings are live right now — these searches show current ARP and similar vintage synth gear on eBay:

Search ARP Explorer I on eBay Browse ARP synth gear on eBay

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.