Abstract: An audio amplifier with amplified feedback having a discrete component amplifier and an amplified negative feedback network. The amplified negative feedback network includes a feedback amplifier, a first resistor network, a second resistor network and a further feedback means for providing local negative feedback to the feedback amplifier and substantially removes a load associated with the output of the discrete component amplifier.

Abstract: A filter capacitor network includes an inductor connected in series with an aluminum electrolytic capacitor with the inductor and aluminum electrolytic capacitor bypassed with a capacitor having relatively better high frequency performance characteristics than the aluminum electrolytic capacitor. The inductor decouples the aluminum capacitor from the network at middle and upper frequencies so that the bypass capacitor dominates the characteristics of the network in that range. A signal coupling/DC blocking capacitor network of the same configuration is also disclosed. An amplifier design includes the filter network in the power supply. The filter network is also disclosed in an audio signal path for use in signal coupling/DC blocking.

Abstract: An electromagnetic bipolar loud speaker of the planar type utilizing a vibratable diaphragm having conductors positioned thereon and uniformly distributed over the vibratable area of the diaphragm to interact with a unidirectional, homogeneous magnetic field generated by a coil surrounding the diaphragm. The loud speaker may be made of a number of diaphragms with different sized vibratable areas and with the same conductor orientation thereon with respect to the supporting frame and energizing magnetic field to cover the wide range of frequency responses.