ARP Rhodes Chroma (1981)

Name: ARP Rhodes Chroma
Brand: ARP

Analog/digital hybrid polyphonic synthesizer developed by ARP and marketed by Rhodes, introduced in 1981.

Overview

The Rhodes Chroma is an analog/digital hybrid polyphonic synthesizer developed by ARP in 1981 and sold under the Rhodes brand due to ARP's financial difficulties. It features a 64-note, velocity-sensitive, piano-touch keyboard and supports optional polyphonic aftertouch. The instrument is highly regarded for its rich, creamy, and fat sound, expressive playability, and innovative architecture, offering extensive modulation and sound design capabilities. It entered a market dominated by the Sequential Prophet-5, Minimoog, Jupiter-8, and OB-X, and remains a favorite among players despite its challenging user interface.

Specifications

Year	1981
Made in	United States
Polyphony	Configurable for 16-voice (1 oscillator) or 8-voice (2 oscillators)
Memory	50 user memories

Design

The Rhodes Chroma uses full analog audio generation with XR4151 VCOs, Curtis filters, and VCAs, combined with digital control for envelopes, routing, and modulation. It features two oscillators per voice, a multi-mode filter with digitally controlled resonance (7 steps), two ADSRs, and a VCA, with signal routing options including parallel or series filters and pre- or post-filter VCA placement. The internal computer enables 16 virtual patch configurations, allowing deep reconfiguration of VCOs, VCFs, and VCAs. Digitally generated ADSR envelopes and 16 LFOs with multiple waveforms provide advanced modulation. The user interface consists of a membrane panel, often criticized for usability and reliability. Sound data is stored on cassette tape, and the original system used a specialized Apple ][ interface.

Context

Developed by ARP and marketed by Rhodes, the Chroma was introduced in 1981 into a competitive market led by the Sequential Prophet-5, Minimoog, Jupiter-8, and OB-X. It is considered relatively rare and was influential on later synthesizers. Notable users include Herbie Hancock. The Chroma Polaris and Chroma Expander are related models, with the Expander capable of increasing voice count to 32/16. The instrument is multitimbral, supports voice layering and keyboard splitting, and can be upgraded with modern solutions like the CC+ MIDI retrofit and StereoPing controller.

Market

The Rhodes Chroma is a vintage, discontinued instrument with current used market prices in the $8,000 - $9,000 range. Common issues include flaky power supplies, failing membrane panels, leaking batteries, keyboard action problems, voice failures, and uneven keyboard response, making it a maintenance challenge. It is large and heavy, with a 25-pin Chroma interface for connecting to the Chroma Polaris. Modern control options include iPad/Lemur, Behringer BCR2000 sysex templates, and custom controllers from StereoPing and Red Shift.