Microphone with rounded magnet motor assembly, backwave chamber, and phantom powered JFET circuit

• US 9,888,315 B1
• Filed: 10/19/2015
• Issued: 02/06/2018
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: Cloud Microphones, LLC
• Original Assignee: Cloud Microphones, LLC
• Inventors: Cloud, Rodger, Sank, Stephen
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Zhu, Qin
• Application Number:
  US14/887,082
• Time in Patent Office: 841 Days
• Field of Search: None
• CPC Class Codes: H04R 1/08 Mouthpieces; Microphones; Attachments therefor
• CPC Class Codes: H04R 1/083 Special constructions of mouthpieces
• CPC Class Codes: H04R 1/222 for microphones H04R1/24, H04R1/26 take precedence
• CPC Class Codes: H04R 1/2876 by means of damping material, e.g. as cladding damping material for tuning desired resonances H04R1/2807, e.g. in vents H04R1/2823, H04R1/2846
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 9/025 Magnetic circuit
• CPC Class Codes: H04R 9/048 of the ribbon type

Abstract

A novel ribbon microphone incorporates rounded-edge magnet motor assembly, a backwave chamber, and a phantom-powered JFET circuit. In one embodiment of the invention, one or more novel rounded-edge magnets may be placed close to a ribbon of the ribbon microphone, wherein the one or more novel rounded-edge magnets reduce or minimize reflected sound wave interferences with the vibration of the ribbon during an operation of the ribbon microphone. Furthermore, in one embodiment of the invention, a novel backwave chamber operatively connected to a backside of the ribbon can minimize acoustic pressure, anomalies in frequency responses, and undesirable phase cancellation and doubling effects. Moreover, in one embodiment of the invention, a novel phantom-powered JFET preamplifier gain circuit can minimize undesirable sound distortions and reduce the cost of producing a conventional preamplifier gain circuit.

Claims

1. A phantom-powered JFET preamplifier gain circuit for a microphone or a musical instrument, the phantom-powered JFET preamplifier gain circuit comprising:

a first JFET having its gate terminal coupled to a positive signal input terminal, which is configured to receive at least one sound source signal;

a second JFET coupled to a negative signal output terminal, wherein the second JFET is also coupled in cascode to the first JFET and is powered by an external phantom power supply;

a third JFET having its gate terminal coupled to a negative signal input terminal, which is configured to receive the at least one sound source signal; and

a fourth JFET coupled to a positive signal output terminal, wherein the fourth JFET is coupled in cascode to the third JFET and is powered by the external phantom power supply.

2. The phantom-powered JFET preamplifier gain circuit of claim 1, wherein the at least one sound source signal is a microphone signal from the microphone or a sound signal from the musical instrument.

3. The phantom-powered JFET preamplifier gain circuit of claim 1, further comprising one or more resistors coupled to the first JFET and the third JFET within the phantom-powered JFET preamplifier gain circuit.

4. The phantom-powered JFET preamplifier gain circuit of claim 1, further comprising one or more gain-setting feed resistors, wherein the one or more gain-setting feed resistors are coupled to the positive signal output terminal or the negative signal output terminal of the phantom-powered JFET preamplifier gain circuit.

5. The phantom-powered JFET preamplifier gain circuit of claim 1, further comprising an RC network including an additional resistor and an RF shunt capacitor, wherein the RC network enables the phantom-powered JFET preamplifier gain circuit to be used as an external box powered by the external phantom power supply to the microphone without radio frequency interference associated with a cable length.

6. The phantom-powered JFET preamplifier gain circuit of claim 1, further comprising a series capacitor, a bypass switch, and a potentiometer to the positive signal input terminal and the negative signal input terminal as a bypassable high-pass filter with a variable input load.

7. The phantom-powered JFET preamplifier gain circuit of claim 1, wherein an additional JFET is in parallel to at least one of the first JFET, the second JFET, the third JFET, and the fourth JFET.

8. The phantom-powered JFET preamplifier gain circuit of claim 4, wherein the one or more gain-setting feed resistors also provide electrical power to the phantom-powered JFET preamplifier gain circuit.

9. The phantom-powered JFET preamplifier gain circuit of claim 1, wherein the microphone is a ribbon microphone, a condenser microphone, or a dynamic microphone.