Suppression Trigger

The Upper Voicing Board contains three 4' gate arrays and three 8' arrays the remaining arrays are on the Lower Voicing Board. All of the arrays have the base pin (7) grounded. Each of the sawtooth waveforms are supplied to an emitter through a 100Kohm resistor (e.g. Tone G 4 is supplied through resistor pack Z30 pins 5 and 6 to pin 12 of Z31.). Keying voltages (denoted by KV) are supplied to the emitters also through l50Kohm resistors (e.g. KV21). As long as the keying voltage is at or near 0...

323 Bass Keying Voltage

(Refer to Lower Voicing Schematic, sheet 3 of 3.) The T point of the Bass Keying Reference Generator supplies a voltage to the bass of Ql-20 of the Bass Low Note Priority Circuit which is at least three diode drops higher than the keying voltage supplied to the Lower keyboard bus rod (P1-14). The diode drops are created using CR114, Q30 and CR113. This insures that Q1-20 will be biased ON regardless of the bus voltage which decreases as more keys are depressed. (Refer to Lower Voicing...

326 Waveform Control

(Refer to Lower Voicing Schematic sheet 3 of 3.) The Waveform Control sets the bias point of the clipping diodes in the Wave Shaping circuits for each key. When the output of Z53 is 0 volts, sawtooth waveforms are produced. When the output of Z53 is +15 volts, the hollow sound is produced. J11 -6 is ground when the Waveform Enhancement switch is off, +15 volts when the switch is on. CR107 provides a little extra voltage to the output when the input is + 15 volts since the op amp cannot supply...

37 Bass Voice Circuit

This circuit contains a preset Bass Voltage Controlled Filter, Envelope Generator, String and Synthesizer VCA, and the Main Output Mix Amplifier. The Bass Voltage Controlled Filter, comprised of 24A, C6, Z4B, and C7, form a two pole low pass filter. The Bass Waveforms (8' and 16') are summed in on J15-2 and J15-3. 24A and B act as voltage controlled resistors, whose transconductance is controlled by the voltage at the gates. The initial conduction (or the initial cutoff frequency) is regulated...

Section 6 Parts List32

The ARP OMNI-2 offers the unique combination of polyphonic tone sources and the versatility of synthesizer sound modification. Separate string and synthesizer sections allow orchestral and symphonic sounds simultaneously. The total variability of the synthesizer section permits such sounds as brass, piano, and clavinet without single note limitations. The string, bass and synthesizer sections have separate outputs located on the rear panel. ARP's now-famous systems interface applies to this...