hifisonix

Tag: audio amplifier

  • More Notes On Cascode Amplifier Oscillation

    Here is a short write up on cascode oscillation I did back in 2012 when designing and developing the e-Amp. Cascode Oscillation in Audio Amplifiers.pdf I recently (2017) had a recurrence of the problem on another high power design – some pictures are shown below.  When I went back and looked at the notes above,…

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  • Stan Curtis 60W Class A Amplifier from ETI

    Stan Curtis was involved in both engineering and management roles in companies like Quad, Cambridge, Rotel (a family owned Japanese brand) Mission and Lecson to name a few. He is primarily an audio business consultant and remains highly respected and a noted product designer within the sector in his own right. This is his 60…

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  • OPEX-1: A Discrete OPAMP for Audio

    This design showcases a discrete opamp for audio applications.  It features very low noise, low distortion and a class A output stage that will deliver 1ppm distortion into a 600 Ohm load at 12 V peak. OPEX-1-Discrete-Opamp

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  • Solid State Relay with PCB Layout

    A complete relay that is smaller than a Tyco RT series EMR Simple_solid_state_relay_Updated  . This design uses a small double sided PCB and some SMD components. Here are the Gerber files SSLR.  The recomended mosfets for this design are the  PSMN4R3-100PS[1] for supply rails of up to +-50 V absolute maximum, and for supply rails of up…

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  • Output Coupling Inductors

    Inductors on the output of an amplifer are used to isolate the amplifer from capacitive loads at HF and ensure stability.  There has been quite some debate on DIYaudio.com as to whether they are audible, necessary, or just the result of designers being overly cautious.  Some very well known designers in the field have decided against using…

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  • An Overview Of SID and TIM, Walt Jung et al

    This series of articles on TIM and SID (and subsequent AES paper), were authored by Walter G. Jung and published between 1977 and 1979 in ‘The Audio Amateur’. It should be read in the context of amplifier design as it stood in the late 1970’s: a clear understanding of the mechanism was only just beginning…

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  • Hifisonix Solid State Loudspeaker Relay

      On big power amplifiers, conventional electromechanical relays leave much to be desired when it comes to their ability to reliably switch fault level currents in the event of a catastrophic amplifier fault. In a worst case situation (and I speak from experience), one of the output devices fails short circuit, placing the full amplifier rail voltage across the loudspeaker terminals. Relay…

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  • Ovation SCA-1: A high performance fully balanced line pre-amplifier

      Originally published in 2010 Here is the result of my investigation in to a fully balanced high performance, low distortion line pre-amp, the ‘Ovation’ Stereo Control Amplifier One’. I drew some inspiration for this project after reading about the TEAC Esoteric line preamp, which is also based on the TI PGA2320, and received rave reviews…

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