Some Ideas on Temperature Compensation for Audio Amplifier EF Triples

Temperature compensating an EF3 audio power amplifier output stage is not a trifling task.  There are 6 Vbe junctions, running at 3 different current densities, different temperatures and neither is the thermal performance of the heatsink assembly characterized In most DIY cases. This makes deploying a conventional 2 transistor  Vbe spreader (or Vbe multiplier as […]

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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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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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Michael Kiwanuka: SOA Protection for Audio Power Amplifiers

Power Amplifiers, and especially bipolar output designs, require output stage  protection  in the event of a fault, or the presence of a heavy or highly reactive load.  Michael Kiwanuka explains the intracacies and the design methodology in his paper here  soaprot_12-03-2012  

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