US2967909A - Tremolo - Google Patents

Tremolo Download PDF

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US2967909A
US2967909A US403394A US40339454A US2967909A US 2967909 A US2967909 A US 2967909A US 403394 A US403394 A US 403394A US 40339454 A US40339454 A US 40339454A US 2967909 A US2967909 A US 2967909A
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resistor
tremolo
amplifier
oscillator
low frequency
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US403394A
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Rice Joseph
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H1/00—Details of electrophonic musical instruments
    • G10H1/02—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos
    • G10H1/04—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos by additional modulation
    • G10H1/043—Continuous modulation

Definitions

  • a tremolo effect is often desired for musical instruments and is generally somewhat difiicult to obtain. Some devices have been tried, and in many cases introduced distortions and extraneous signals which were of irritating proportions.
  • the invention comprises an electron tube amplifier to the output whereof is inserted a low frequency wave for modulating a signal passing through the amplifier.
  • an electron tube such as a triode is connected in an electrical circuit to function as an audio amplifier.
  • the triode for example, may conventionally be a half section of a l2AX7 electron tube or any other single or multi-purpose tube.
  • the circuit as shown includes an audio-input circuit which is connected to grid 12 across a load resistor 14 which is connected to a grid 12 at one extremity and the other extremity thereof is connected to a reference point as B-.
  • a cathode 16 is connected to the reference point or B- through a bias resistor 18 shunted by a capacitor 20.
  • Positive potential from the B+ terminal of the power supply is connected to anode 22 through a resistor 24.
  • a low frequency oscillator is formed as a phase shift oscillator and utilizes a second triode 30 which may be the second half of a multi-purpose electron tube such as the l2AX7 heretofore mentioned.
  • the circuitry of the oscillator comprises a grid bias circuit for the phase shift formed by a capacitor 32 and resistor 34 one extremity of each being connected to a grid 36. The other extremity of resistor 34 is connected to the cathode 38 of tube 30.
  • Frequency control is accomplished by means of a dual potentiometer 40 the center arm whereof and one extremity of each section are likewise connected to cathode 38.
  • a resistor 42 is connected to one of the potentiometer elements and a resistor 44 is connected to the other potentiometer elements.
  • Capacitor 32 is connected to one extremity of resistor 42 and through a capacitor 46 to one extremityof resistor 44 and through a further capacitor 48 to the anode 50 and triode 30.
  • Anode pop CC tential is obtained from a 3+ terminal of a source of supply through a resistor 52, to anode 50.
  • the phase shift oscillator is controlled by means of an on-ofi switch 54 which is in series with a resistor 56 and the cathode 38, of tube 30. Output from the oscillator is taken off between cathode 38 and anode 50.
  • the heart of the invention resides in the modulation of the output signal from the audio-amplifier by the output signal from the low frequency amplifier and is accomplished through a bridge networking 58 formed of four diodes A, B, C, D and having a resistor 60 as a load. The operation of this bridge will be hereafter discussed.
  • the oscillator output is coupled through capacitor 62 and 64 to an H pad E formed of resistors 66, 68, 70, 72 and variable resistor 74.
  • the output signal is taken off load resistor 76 through a capacitor 78.
  • the audio-amplifier amplifies a signal which appears across load resistor 28 and is coupled to load resistor 28 and load resistor 76.
  • output current flows through diode C bridge resistor 60 and diode B and on the other half cycles flows through diode A bridge resistor 60 and diode D.
  • a modulating signal from the low frequency generator obtained from the H pad E is applied across bridge load resistor 60 through wires F and G.
  • signals appearing across bridge load resistor 60 are affected by the modulating signal obtained from the low frequency oscillator. This modulation results in the tremolo effect.
  • phase shift oscillator is balanced for its output facilitating injection to the balanced modulator or bridge network. Balance is accomplished by means of substantially equal value load resistors in the cathode and anode circuit.
  • 19w firequency oscillator means for adjusting said 5 References Cited in the file of this patent frequency oscillator to a predetermined constant frequen UNITED STATES PATENTS cy and means for mixing a signal passing through said 2,233,860 Wise Man 4, 1941 audio amplifier with the predetermined low frequency 2 4 5 533 Rowe Oct 1 1949 signal from said low frequency-oscillator, said means in- 2,534,342 Da i l D 19, 1950 eluding a bridge rectifier circuit including a low resistor 10 2,682,640 Harling June 29, -1954

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Amplifiers (AREA)

Description

Jan 10, 1961 J. RICE 0 TREMOLO 7 Filed Jan. 11, 1954 DUAL FREQ.
CONTROL INVE TOR YWL WWW United States Patent TREMOLO Joseph Rice, 103-26 68th Ave., Forest Hills, Queens, NY.
Filed Jan. 11, 1954, Ser. No. 403,394
1 Claim. (Cl. 179-1) This invention relates to a tremolo for use with musical devices.
A tremolo effect is often desired for musical instruments and is generally somewhat difiicult to obtain. Some devices have been tried, and in many cases introduced distortions and extraneous signals which were of irritating proportions.
It is a prime object of the invention to provide an electronic tremolo which may be utilized with instruments normally connected to electronic amplifier circuits.
It is a further object of the invention to provide an improved tremolo having a variable frequency range.
It is another object of the invention to provide an improved tremolo which is economical to manufacture and positive in action.
In general, the invention comprises an electron tube amplifier to the output whereof is inserted a low frequency wave for modulating a signal passing through the amplifier.
The invention is more fully described in the following specification taken with the figure which is a circuit diagram of an illustrative amplifier and low frequency generator embodying the invention.
Referring to the drawing in detail, an electron tube such as a triode is connected in an electrical circuit to function as an audio amplifier. The triode, for example, may conventionally be a half section of a l2AX7 electron tube or any other single or multi-purpose tube. The circuit as shown, includes an audio-input circuit which is connected to grid 12 across a load resistor 14 which is connected to a grid 12 at one extremity and the other extremity thereof is connected to a reference point as B-. A cathode 16 is connected to the reference point or B- through a bias resistor 18 shunted by a capacitor 20. Positive potential from the B+ terminal of the power supply is connected to anode 22 through a resistor 24. This generally completes the circuit of a conventional type audio amplifier, the output whereof is taken from the anode 22 through a capacitor 26 and applied across a load resistor 28. A low frequency oscillator is formed as a phase shift oscillator and utilizes a second triode 30 which may be the second half of a multi-purpose electron tube such as the l2AX7 heretofore mentioned. The circuitry of the oscillator comprises a grid bias circuit for the phase shift formed by a capacitor 32 and resistor 34 one extremity of each being connected to a grid 36. The other extremity of resistor 34 is connected to the cathode 38 of tube 30. Frequency control is accomplished by means of a dual potentiometer 40 the center arm whereof and one extremity of each section are likewise connected to cathode 38. To provide a frequency range within desired limits a resistor 42 is connected to one of the potentiometer elements and a resistor 44 is connected to the other potentiometer elements. Capacitor 32 is connected to one extremity of resistor 42 and through a capacitor 46 to one extremityof resistor 44 and through a further capacitor 48 to the anode 50 and triode 30. Anode pop CC tential is obtained from a 3+ terminal of a source of supply through a resistor 52, to anode 50.
The phase shift oscillator is controlled by means of an on-ofi switch 54 which is in series with a resistor 56 and the cathode 38, of tube 30. Output from the oscillator is taken off between cathode 38 and anode 50. The heart of the invention resides in the modulation of the output signal from the audio-amplifier by the output signal from the low frequency amplifier and is accomplished through a bridge networking 58 formed of four diodes A, B, C, D and having a resistor 60 as a load. The operation of this bridge will be hereafter discussed.
To suitably match the load resistor 60 the oscillator output is coupled through capacitor 62 and 64 to an H pad E formed of resistors 66, 68, 70, 72 and variable resistor 74. The output signal is taken off load resistor 76 through a capacitor 78.
In operation the audio-amplifier amplifies a signal which appears across load resistor 28 and is coupled to load resistor 28 and load resistor 76. On one half cycles output current flows through diode C bridge resistor 60 and diode B and on the other half cycles flows through diode A bridge resistor 60 and diode D. Simultaneously with this flow of current a modulating signal from the low frequency generator obtained from the H pad E is applied across bridge load resistor 60 through wires F and G. In this manner signals appearing across bridge load resistor 60 are affected by the modulating signal obtained from the low frequency oscillator. This modulation results in the tremolo effect.
The phase shift oscillator is balanced for its output facilitating injection to the balanced modulator or bridge network. Balance is accomplished by means of substantially equal value load resistors in the cathode and anode circuit.
Although I have discussed my invention as it is utilized with one type of audio-amplifier and one type of low frequency oscillator, it is obvious that other types of audioamplifiers, oscillators and other tubes may be utilized with equal results.
In the invention typical values of components utilized with the circuit embodying the invention is herein disclosed as follows:
Resistor 14 ..ohms 470K H Resistor 18 do 1K Resistor 24 -do K Resistor 28 do 47K Resistor 34 megohms 2.7 Resistor 42 ohms 100K Resistor 44 do 100K Resistor 52 do 100K Resistor 56 do 100K Resistor 60 do.. 47K Resistor 66 do K Resfstor 68 do 150K Resistor 70 do 150K Resistor 72 do 150K Resistor 76 do 47K Capacitors 20 tnfd 50 Capacitors 26 'mfd .1 Capacitors 32 mfd .01 Capacitors 46 ..mfd .01 Capacitors 48 n mfd .01 Capacitors 62 mfd .5 Capacitors 64 -mfd .5 Capacitors 78 mfd .1 Dual potentiometer 40 megohms l Potentiometer 74 do 5 Having thus described my invention I desire it understood that variations thereof will be obvious to those a '4 skilled in the art and the claim appended hereto be interand means for impressing the predetermined low frepreted within the spirit and scope of the'invention; quency signal fromsaid low frequency 'o'scillator across What is claimed is: said low resistor. A tremolo including an audio frequency amplifier, a
19w firequency oscillator means for adjusting said 5 References Cited in the file of this patent frequency oscillator to a predetermined constant frequen UNITED STATES PATENTS cy and means for mixing a signal passing through said 2,233,860 Wise Man 4, 1941 audio amplifier with the predetermined low frequency 2 4 5 533 Rowe Oct 1 1949 signal from said low frequency-oscillator, said means in- 2,534,342 Da i l D 19, 1950 eluding a bridge rectifier circuit including a low resistor 10 2,682,640 Harling June 29, -1954
US403394A 1954-01-11 1954-01-11 Tremolo Expired - Lifetime US2967909A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3165640A (en) * 1960-12-15 1965-01-12 North American Aviation Inc D. c. controlled semiconductor switch for a. c. current
US3236931A (en) * 1960-01-15 1966-02-22 Academy Of Aeronautics Electronic musical instrument
US3490069A (en) * 1966-06-28 1970-01-13 Seeburg Corp Tremolo producing arrangement in which the tremolo signal is isolated from the audio circuit
US3597633A (en) * 1967-04-07 1971-08-03 Hitachi Ltd Diode bridge type electronic switch
US3629617A (en) * 1970-02-20 1971-12-21 Martin Marietta Corp Voltage-controlled logarithmic attenuator
US5333203A (en) * 1992-05-22 1994-07-26 Cesar Diaz Reverb and selectable tremolo and vibrato electron tube preamplifier

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2233860A (en) * 1939-04-27 1941-03-04 Bell Telephone Labor Inc Modulating system
US2485538A (en) * 1947-05-26 1949-10-18 Maas Rowe Electromusic Corp Electronic means providing tremolo for electrically operated musical instruments
US2534342A (en) * 1947-08-29 1950-12-19 Nathan I Daniel Vibrato means for audio amplifiers
US2682640A (en) * 1951-08-28 1954-06-29 Gen Electric Co Ltd Arrangement for modulating electric carrier wave oscillations

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2233860A (en) * 1939-04-27 1941-03-04 Bell Telephone Labor Inc Modulating system
US2485538A (en) * 1947-05-26 1949-10-18 Maas Rowe Electromusic Corp Electronic means providing tremolo for electrically operated musical instruments
US2534342A (en) * 1947-08-29 1950-12-19 Nathan I Daniel Vibrato means for audio amplifiers
US2682640A (en) * 1951-08-28 1954-06-29 Gen Electric Co Ltd Arrangement for modulating electric carrier wave oscillations

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3236931A (en) * 1960-01-15 1966-02-22 Academy Of Aeronautics Electronic musical instrument
US3165640A (en) * 1960-12-15 1965-01-12 North American Aviation Inc D. c. controlled semiconductor switch for a. c. current
US3490069A (en) * 1966-06-28 1970-01-13 Seeburg Corp Tremolo producing arrangement in which the tremolo signal is isolated from the audio circuit
US3597633A (en) * 1967-04-07 1971-08-03 Hitachi Ltd Diode bridge type electronic switch
US3629617A (en) * 1970-02-20 1971-12-21 Martin Marietta Corp Voltage-controlled logarithmic attenuator
US5333203A (en) * 1992-05-22 1994-07-26 Cesar Diaz Reverb and selectable tremolo and vibrato electron tube preamplifier

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