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The Audio Circuits Cookbook
Page xxi: The link to the Rane Legacy page is wrong. This is correct: https://www.ranecommercial.com/legacy
Page 14: The wording in the first sentence of the main paragraph is confusing. Replace this:
In this case the resistance is about 8.2k with 1 volt bias, and 770 ohms at 8 volts.
with this:
In this case the resistance is about 8.2k with 1 volt into 10k resistor R2 (55 microamps), and 770 ohms at 8 volts (745 uA).
Page 7, between the last two paragraphs add this paragraph:
Note that capacitors can distort the audio passing through them only when the signal level changes through the capacitor. With coupling caps in series, all of the audio above 10-20 Hz gets through. And at very low frequencies none of the audio gets through. Distortion occurs only when some of the audio passes and some is blocked. So while it's best to use film capacitors in the signal path for their low distortion, this applies mostly for equalizers and other filters where the capacitor's loss occurs within the audible pass-band.
Page 48: Add this at the end of the Attenuators and Pads section just before the Parallel Resistors section head:
Note that R1 and R2 in the H-pad need to be matched closely to maintain adequate common mode rejection. Using 1% tolerance resistors assures 40 dB rejection, and 0.1% resistors increase that to 60 dB.
Page 64: Figure 4.14 has incorrect resistor labels for Simulated Inductor C. R3 through R6 should be R1 through R4 to match the formula at the bottom of the page.
Page 69: Figure 4.17 is missing the closing parenthesis on SINE(0 1 100). The online LTspice file may also be missing that parenthesis.
Page 69, last paragraph, add this at the end to be the last sentence:
The online Decibels spreadsheet can calculate distortion amounts from dB level differences and vice versa.
Page 84: add this sentence to the end of the first (partial) paragraph:
If you need a square wave with a fixed duty cycle, you could use two frequency doublers in series, then halve that frequency.
Page 130: The text that accompanies Figure 6.9 explains the difficulty in determining the correct direction for an electrolytic capacitor due the unknown polarity of an op-amp's input offset voltage. My expert friend Bill Eppler showed me a clever way to solve this, but its too much to explain here. So I made THIS separate page.
Page 169: Three new VCO circuits are available in the online Zip file: VCO 2 and VCO 3 are simpler than the VCO in the book, though they output only triangle and square waves. VCO 4 is full-featured, and improves on the book's VCO by extending its output to allow seven octaves, plus a few other circuit improvements.
Page 171: In Figure 7.5 the closing parenthesis on the PWL line is missing. The online LTspice file may also be missing that parenthesis.
Index, add: pages 8 and 68 to Impedance
Index: Add Rail (op-amp power) 29, 42, 56, 73, 81, 141
Ethan Winer has been a professional audio engineer and musician for most of his adult life. He now heads up RealTraps, where he designs acoustic treatment products for recording studios and home listening rooms.
Entire contents of this web site Copyright © 1997- by Ethan Winer. All rights reserved.