A V V lTt15

7-i-0 GATE BUS


Arp 4023 Filter Schematic

y fil


The 4023 voltage controlled filter is no longer available from the Factory. Instead, the newer 4075 filter can be used to replace the 4023 with the following modification (see Field Change Notice 007):

The earlier model Odyssey-lls used a 4035 voltage controlled filter, which has since then been replaced by the 4075. No modifications are necessary when replacing a 4035 filter with a 4075.

4023 Vcf Schematic

Change T4

to 100 ohm trimmer

J^* Break connection

Change T4

to 100 ohm trimmer

J^* Break connection


The newer style Odysseys use a zener diode as a noise source instead of a noise transistor. Defective noise transistors can be replaced with a zener diode, provided the following circuit modification is performed:

Zener diodes tend to produce a greater spectrum of white noise with little or no noise break-up.

Arp Noise Generator

1.9 Specifications Noise Generator

Noise spectrum types: White and Pink

Voltage Controlled Oscillators

Waveforms: Sawtooth, Square, Pulse, Dynamic Pulse Frequency range: VCO 1 in low freq. mode, .2 Hz to 20 Hz; VCO 1 and VCO 2 (audio range), 20 Hz to 20 KHz Warm up drift: 1/30 semitone from turn on max. Pulse width: 50% to 5%

Pulse width modulation: ADSR, +45%; LFO, +15% Voltage controlled response: 1V/oct. Maximum frequency shifts: LFO sine wave, +1/2 oct.; LFO square wave, +1.5 oct.; ADSR +9oct.; S/H +2 oct.

Note: VCO 1 is a low note priority; VCO 2 is high no te priority


Positions: Down 2 octaves, normal, up 2 octaves

Pitch Bend

Frequency shift: About + 1 oct. (exactly 1 octave on Odyssey-2)

Frequency shift: About 5 semitones ±1 semitone.


Maximum speed: About .01 msec./oct. Minimum speed: About 1.5 seconds/oct.

Ring Modulator

Type: Digital

Input signals: VCO 1 and VCO 2 pulse waves

Voltage Controlled Filter

Type: Low pass

Frequency range: 16 Hz to 16 KHz Maximum usable O: 30 Resonance 1/a to self oscillate Voltage controlled response: 1V/oct.

Voltage Controlled Amplifier

Dynamic Range: 80dB

Sample and Hold

Command sources: Keyboard or LFO trigger Sampled signals: VCO 1 square wave and sawtooth wave, VCO 2 square wave and pink noise

ADSR Envelope Generator

Attack time: 5 msec, to 5 seconds Decay time: 10 msec, to 8 seconds Sustain level: 0 to 100% of peak Release time: 15 msec, to 10 seconds

AR Envelope Generator

Attack time: 5 msec, to 5 seconds Release time: 10 msec, to 8 seconds

Audio Outputs

High level: 2.5VPP max.; 100K impedance Low level: .25VPP max.; 10K impedance

I nterface Jacks

Keyboard CV IN/OUT: 1V/oct.

Gate OUT: +10V, key down; 0V all keys up

Gate IN: +8V minimum

Trigger OUT: +10V pulse on key depression, 10

microsec. duration Trigger IN: +8V pulse min., 10 microsec. duration minimum

External Audio Input: 500 millivolts for full output

+2 -1

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