The coupling capacitor CG blocks the high DC voltage at the plate of the driving tube while allowing audio signals to pass:
Unless bass attenuation is desired the capacitor needs to be large enough to induce very little signal attenuation at bass frequencies. (82Hz is the lowest note on a guitar with standard tuning.) It shouldn't be too large, however, or unwanted effects like blocking and motorboating may ensue.
The calculator computes the gain at various frequencies based on the capacitor value and volume control setting. It assumes that attenuation due to the grid-stopper resistor RGS, if used, is only significant above audio frequencies.
This new approach to guitar amplifier electronics embraces 2018 technology to deliver greater understanding with less math. Computer-based visualization replaces the traditional litany of mathematical formulas. The book's graphing calculators, free on this website, are designed for smartphones and laptops, making them as portable as the book that uses them.
Less Math, Greater Understanding
The book explains the principles of vacuum tube electronics and the design of preamp voltage amplification stages, cathode followers, tone stacks, power amps, phase inverters, negative feedback, and power supplies. An entire chapter is devoted to sculpting the dynamics of overdrive and harmonic distortion.
Copyright © 2018 Amp Books LLC All Rights Reserved