ARP Odyssey 2813 (1976–1978)

That snarling, searing lead on “Autobahn” didn’t come from a Minimoog - it was this black-and-gold beast with the buttons that never quite worked right.

Overview

The ARP Odyssey bites off its notes and snarls through guitar amps. The 2813 is the Mark II model, born in 1976, when synth design was shifting from lab-curious to stage-ready. It wore a black panel with gold lettering. It wasn't the flashiest synth, but it showed up to gigs, stayed in tune, and didn't apologize for its weight or its temperamental sliders.

The 2813 sits in the middle of the Odyssey’s second generation - not the earliest with the Moog-style filter, not the later orange-faced Mk IIIs with the steel chassis, but right in the transition. It kept the twin VCOs that made ARP famous, with full PWM, oscillator sync, and ring modulation. The duophonic keyboard scanning was ARP’s workaround for limited polyphony. It let you play two notes at once with independent oscillator assignment, which felt almost magical in 1976. The Minimoog was content being a soloist. The Odyssey worked as a lead, a bass, and a sound effects generator all at once.

Not all 2813s are created equal. This model shipped with the 4075 filter, a 4-pole low-pass design ARP developed after a quiet truce with Moog over filter patents. It was supposed to be a beefy, self-oscillating ladder filter, but a miscalculation in the component values capped its maximum cutoff frequency around 12kHz. That gives it a slightly veiled top end compared to the earlier 4035 “lawsuit” filter. Purists say the 4035 models (mostly 2810s) sound “open” and “alive,” while the 4075 sounds darker and more restrained. They're both right. The 4075 isn’t broken, just different. It's less “screaming eagle” and more “growling panther,” with a low-mid snarl that cuts through dense mixes without fizzing out. It's the filter behind Gary Numan’s icy leads and Herbie Hancock’s funkier excursions. It's not the most open-sounding analog filter ever made.

Then there's the PPC, the Proportional Pitch Controller. The 2813 came from the factory with three rubber pressure buttons on the left side, replacing the pitch-bend knob of the original Mk I. In theory, you press harder for more pitch bend and add vibrato with fingertip control. In practice it's awkward. The buttons wear out, the rubber cracks, and the response is inconsistent. Many players either mod it with a joystick or leave it be and use the modulation wheel, which the Odyssey doesn't even have.

Specifications

Manufacturer	ARP Instruments, Inc.
Production Years	1976–1978
Model Number	2813
Series	Mark II
Keyboard	37 keys, duophonic
Polyphony	Monophonic / Duophonic
Oscillators	2 VCOs with sawtooth, square, pulse, PWM, noise
Filter Type	4075 4-pole low-pass VCF (24dB/octave)
Filter Features	Resonance, self-oscillation, external audio input
LFO	Sine and square waveforms
Envelopes	Two ADSR envelopes
Modulation	Oscillator sync, ring modulator, sample & hold
Pitch Control	Proportional Pitch Controller (PPC) – three pressure-sensitive buttons
CV/Gate	CV In, Gate In, Trigger In, S&H Clock Out
Audio Input	Yes, via rear panel
Outputs	1/4" and RCA (originally low and high, often modified)
MIDI	No (pre-MIDI era)
Power Supply	Internal, 120V AC (60Hz)
Weight	25 lbs (11.3 kg)
Dimensions	35.5" x 12.5" x 4.5" (90 x 32 x 11 cm)
Color Scheme	Black panel with gold lettering, vinyl wrap-around case
Original Price	$1,595 (1976)

Key Features

The 4075 Filter: Flawed Genius

The 2813’s 4075 filter is a design born of compromise. After ARP’s earlier 4012 filter was found to infringe on Moog’s ladder patent, the company rushed to develop a non-infringing alternative. The 4075 was that answer, but a calculation error limited its high-frequency response, capping out around 12-14kHz. So when you crank the resonance or push it into self-oscillation, it doesn’t scream into the stratosphere like a Minimoog or a Prophet-5. It growls, with a focused midrange bite and a slightly rolled-off top end. Some call that a flaw. Others call it character. It won’t give you the crystalline highs of a clean oscillator sweep, but it will cut through a rock mix like a chainsaw. It made the Odyssey a favorite for aggressive leads, dubby basslines, and anything that needed to sound dangerous without turning into noise.

Duophony and the Odyssey’s Secret Weapon

Most synths of the era were strictly monophonic. The Odyssey’s duophonic mode was a clever hack. When you played two notes, the synth assigned one oscillator to the highest note and one to the lowest, so you could play intervals or simple chords with real voice independence. It wasn’t polyphony, but it was close enough to feel expressive. The 2813 inherited this from the original Odyssey. To play a fifth with a fat, detuned sound, just hold two keys. The oscillators split, and with a touch of PWM or filter modulation the sound gets richer than a single voice. It's not perfect. Tracking can be finicky, and fast runs sometimes stutter.

Build and Reliability: Tough, But Not Bulletproof

The 2813’s chassis is the same wrap-around vinyl-covered wood used in earlier models. It's sturdy but prone to dings and edge wear. The sliders, those vertical faders, are the weak spot. They crack, wear out, and develop scratchy contact. Original sliders are nearly impossible to find NOS, and replacements often feel clunky. Some owners swap in modern Bourns faders or LED-lit assemblies, which improve feel and reliability at the cost of originality. The keyboard is serviceable, with no velocity or aftertouch, but key bushings wear out and the contacts can get dirty. A full service usually includes recapping, IC replacement, and a keybed overhaul. Do it right, and the 2813 will run for decades. Skip it, and you'll spend more time troubleshooting than playing.

Historical Context

The 2813 arrived in 1976, right when the synth market was exploding. Moog had the Minimoog, Yamaha was pushing the CS series, and Roland was about to drop the Jupiter-4. ARP needed to keep the Odyssey competitive, and the Mark II series was their answer. It was a refinement, not a radical redesign. The black-and-gold panel replaced the early white-faced models, the circuitry was updated for better stability, and the PPC replaced the pitch knob. Behind the scenes, ARP was fighting for survival. Competition was fierce, costs were high, and the company was burning cash. The 2813 was a workhorse, built to last on the road and deliver consistent performance. You can hear it on records by Ultravox, Kraftwerk, and Chick Corea. ARP folded in 1981.

Collectibility & Value

Today, the 2813 trades in a sweet spot between rarity and usability. It's not as rare as the white-faced Mk Is or the Moog-filtered 2810s, but it's not as common as the orange-faced Mk IIIs. Expect to pay $2,500 - $3,500 for a clean, fully serviced unit. Unserviced models can be found for $1,800 - $2,200, but add $500 - $800 for a professional recap and slider replacement, and the math changes fast. Condition drives the price: look for strong silkscreening (the gold lettering wears off easily), intact sliders, and a responsive keyboard. Avoid units with cracked panels or heavily modded insides unless the work was done by a reputable tech.

Common failures: tantalum capacitors in the power supply and filter board are notorious for leaking and failing, so replace them all. The PPC buttons crack and lose sensitivity. The original ICs (especially the CMOS chips) degrade over time, causing glitches or no sound. The sliders are the biggest headache. Many 2813s have been retrofitted with LED sliders or Bourns faders, which improves playability but lowers collector value. For a museum piece, stick to stock. For a gigging synth, the mods are fine.

Before buying, test every slider, check for filter self-oscillation, verify oscillator tracking across the keyboard, and inspect the PPC response. Power it on and let it warm up for 15 minutes, since ARP synths need time to stabilize. If it drifts more than a quarter tone, it needs service. If the noise floor is high or the output is weak, suspect failing op-amps or caps.