Macrofab Engineering Podcast

The Vox in a Box Roxs Stephen's Vox in a Box Preamp Design Vox AC30 preamp - 3 gain stages with a cathode follower and a phase inverter Phase inverter - create differential signals for the power amp input Drop signal using voltage dividers and mosfet buffers 320V phase inverter to 18V buffer drive Built point to point on an aluminum plate for easy modification and testing Power Amp Design TPA3116 Class D amplifier LM311 comparator mute circuit for start up mute ~5 to 10 Seconds Runs at 400KHz - Left open pads for boosting this up to 1.2MHzIs there an advantage at running at higher frequencies? Power Supply Design TPS40210 Switching controller into a diode/cap ladder voltage multiplier 7 stages of multiplication leads to ~50V per stage Variable Switching from 35KHz to 1000KHz PMP8621 Appnote Testing the Vox in a Box Been going nonstop for weeks now Have taken it up to nearly 60 Watts without problems Layout of the PCB Multiple ground system with master start Each sub circuit has its own ground re