Marmon Company

Hammond Incorporated

Wilford R Schreier

Horace E Taylor

An improved envelope generator circuit for an electronic organ provides a musically correct attack rate, i.e., the volume of a musical note is increased by an equal number of decibels for equal increments of time. The envelope generating circuit comprises a constant current source for charging a capacitor to generate a linearly increasing voltage signal upon the initial activation of any one or more keys of an electronic organ keyboard. A regulator circuit comprising an operational amplifier and a matched pair of transistors with one transistor connected into the feedback path for the operational amplifier generates an anti-logarithmic control signal in response to the linearly increasing voltage signal. The antilogarithmic control signal is used to control the amplification of a controlled amplifier to which music signals from the organ are passed. The amplifier amplifies the musical signals in accordance with the control signal to generate an output which increases in volume an equal number of decibels for equal periods of time.

Envelope generating circuit for an electronic musical instrument

In an electronic organ including at least two frequency controlled delay circuits controlled by varying frequency output signals from individual voltage controlled oscillators, an analog modulating and intermixing circuit provides an even vibrato effect by controlling the input signal to the voltage controlled oscillators. The amplitude of a vibrato signal which is mixed with a main voltage control signal for a voltage controlled oscillator to provide a vibrato effect is modulated by the primary voltage control signal. The primary voltage control signal is amplified and passed to the control input of a voltage controlled amplifier which receives the vibrato signal. The amplified primary voltage control signal is mixed with the output of the voltage controlled amplifier to generate the control signals for driving the voltage controlled oscillators. In this way, the magnitude of the vibrato signal mixed with the primary voltage control signal is proportional to the amplitude of the primary voltage control signal such that its effect on the voltage controlled oscillator is uniform throughout the magnitude ranges of the primary voltage control signal.

Electronic musical instrument including improved vibrato

A harmony generating circuit generates high harmony signals in response to coincident lower manual accompaniment signals and upper manual melody signals. Gating circuitry responsive to coincident inputs from accompaniment chords played on the lower manual and melody notes played on the upper manual generate harmony notes on the upper manual which correspond to the accompaniment notes played on the lower manual but are above the melody notes and approximately within one octave of the melody notes.

Harmony generating circuit for a musical instrument

A one key chording system for an electronic keyboard instrument of the type in which a single contact keyboard for DC keying of tone signals is employed. A primary keying signal from the single contact keyboard operates one of a plurality of chord gates to produce a chord keying signal which is translated by one of a set of chord logic units into secondary keying signals. The primary and secondary keying signals operate keyers for tone signals corresponding to a musical chord. An inhibit circuit prevents chord gates from responding to secondary keying signals. A mode control circuit switches the single key chording system off to return the instrument to normal operation with multiple key chording.

One key chording system for an electronic keyboard instrument

Delayed vibrato and burble circuit in which a single gate between a free running modulating signal oscillator and a master voltage controlled oscillator selectively controls both functions in response to control signals from a keyboard which are processed by parallel time constant circuits.

Delayed vibrato and burble circuit

A plural mode envelope generator in which a basic time constant circuit is coupled by selector switches to a plurality of envelope generating means which function under the control of one or both of a keydown detector and a legato pulse generator. Fast attack-short substain and slow attack-long sustain envelope circuits involve standard techniques. A dual mode percussion circuit provides post key release sustain in one mode when the keydown detector is decoupled from the circuit and post key release tone snubbing when the keydown detector is coupled to the circuit. A sostenuto circuit with flip-flop latch includes a reset gate to hold the flip-flop in reset until sostenuto keying is desired whereupon a unidirectional circuit couples the initial keydown signal to the latch to place the flip-flop in a set state but prevents the disappearance of that signal from resetting the latch.

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Bensenville, IL, United States of America

Wilford R Schreier