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Books offered.

Mapping the Guitar Fingerboard

Authored by Wayne Stegall

Mapping the Guitar Fingerboard is a unique and concise guide to learning the fingerboard of the guitar. Regular practice will produce instant recall of every note on the guitar fingerboard in all locations of occurrence. No claim is made of trivial learning ease, all worthwhile endeavors require work. Instead, I assert instead that the study material presented is efficient. more....

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Unseen Enemy

An Eyewitness Account of the Betrayal of America

Authored by Stegall

A chance encounter with persons associated with espionage activities make me a target of ongoing covert operations. In the course of doing so, my adversaries stir a maelstrom of trouble seemingly significant to the course of prophecy and to the future of the nation. The truth is stranger than fiction. Very strange!

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For other Amazon sites or if these links break enter my name in Amazon search box.

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Audio Home Page

Circuits or calculations should not be breadboarded until they are proven by SPICE simulation. Even then breadboard and test a prototype before committing to a final circuit. Unproven circuits or ideas are for mental stimulation only. Note also that mistakes usually go unnoticed until I find and fix them; therefore I recommend letting ideas sit for a while before considering them complete. For this same reason I try to provide proofs where reasonable or possible so that the user of an idea can verify it before use.

First Things

Audio Philosophy August 5, 2011
Intellectual Property Concerns August 5, 2011. Declaring your freedom to use DIY ideas.
My Favorite Source Component November 3, 2017.

Theory

Phono Equalization Calculations Updated February 6, 2014 .Added schematic and design equations for op-amp based current-input circuit. Updated March 17, 2014. Expanded derivation of two stage equalization equations to more easily show how current-input equalization derives from them. Added more topologies and detail for current input designs..
When Is Phase Shift not Phase Shift? January 2, 2009
Linear Phase Sinc Compensation Filter for Zero-Oversampling DACs January 26, 2009
Mathematical Consideration of Some of the Limitations of Digital Audio May 23, 2009
Phono Termination Calculations and Calculator August 10, 2009. Updated September 13, 2012 Raised program version to 3.3.0 adding shortcuts for entry of Bessel and Butterworth Q values.
Active Inductor Load Updated March 11, 2010. Changed designation for MOSFET constant to proper k_n.
Power Supply Ripple Calculations and Capacitor Size December 6, 2009
Simple Noise Calculations Updated February 27, 2010. Recalculated RIAA noise bandwidth by numerical integral.
Musical Feedback Amplifiers Updated November 2, 2010. Added AD847 to list of Possibly Musical IC Operational Amplifiers and a link to its datasheet.
Simple DC Servos Updated July 21, 2010. Spice verified. First order servos reduce amplifier DC offset without fear of oscillation. Musical Feedback Amplifier example. Elaborated servo equations to better clarify integrator response.
A Musical View of Distortion August 31, 2010
Transfer Curve Shape and Distortion January 1, 2011. Multiple bends in transfer functions reduce distortion quality. Updated January 6, 2011. Added investigation into distortion masking and made an immediate model correction to same.
Flicker Noise Calculations January 26, 2011. Noise of unknown origin causes a rise in noise at low frequencies.
Managing TIM February 26, 2011. Practical means to avoid a difficult-to-measure form of distortion.
Distortion Cancelation May 26, 2011. Three simple distortion cancelation concepts. Updated May 31, 2011. Added SPICE verification of voltage mirrors. Updated June 8, 2011. Recommended use of voltage mirror for BJT circuits only for unity gain pending further investigation. SPICE results problematic with gain, only unity gain producing the desired results. See text. Updated June 11, 2011 Added SPICE verification of integer-gain BJT voltage mirror.
Optimizing the Class B Emitter Follower August 5, 2011. Is current drive better than voltage drive?
Local Feedback August 27, 2011. Is Local Feedback the same concept as Global Feedback? Updated September 26, 2022. Correct Compensated Phase Margin in chart where values transposed.
Apples and Oranges October 2, 2011. A simple proof that class-A and class-B distortion specifications are not comparable.
Phono Preamp Input Protection November 3, 2011.
Transistor Preference December 14, 2011. The effect of transistor choice on distortion performance
One-Bend Amplifier January 31, 2012. Part 1: Compare a current-feedback amplifier allowing a one-bend distortion characteristic to its voltage-feedback equivalent. Updated March 14, 2012 Added correction concerning output stage transconductance factor and added a link to the next article.
Digital Audio Formats April 18, 2012. Updated April 19, 2012 Added graph illustrating how oversampling improves analog filter application. Updated April 20, 2012 Added extra material correcting presumptions contrary to the limitations of the successive-approximation ADC.
Feedback Distortion Analysis August 11, 2012. Taming the capricious transfer curve. Updated August 11, 2012. Added footnote about polynomial representation, improved some wording, added derivation of gain polynomial from transfer curve polynomial, and added an example of long division.
Understanding the S-Domain October 26, 2012. Updated October 27, 2012. Added Q to legend of figure 6 and another link under examples.
Delta-Sigma Modulators January 15, 2013. Their basic theory of operation. Updated January 16, 2013. Corrected some grammar and added an extra phrase of text and graphs of analog FIR filter kernels.
Single-slope Safe-area Limiter March 16, 2013. And other transistor limiters. Updated April 5, 2013. Added an improved component calculation sequence and additional power calculations.
Electrical-Mechanical Equivalence April 27, 2013.
Analog is Digital May 24, 2013. Quantum mechanics defines quantization of analog signals comparable to that of digital audio.
Thermal Design July 12, 2013. Part 1: Thermal design for gainclone and one-bend amplifiers is used to illustrate the presented theory.
Thermal Design August 17, 2013. Part 2: Thermal design for one-bend amplifier is used to illustrate theory advanced to include thermal capacitance. August 23, 2016. Restored missing subfile to SPICE model.
Square Law September 17, 2013. How the square-law of field-effect devices arises from physics.
Room Effect and Speaker Alignment December 6, 2013.
Differential Equalization May 27, 2014. Differential circuit transformation has application to differential RIAA equalization.
Perspective August 16, 2014. The mathematics of the perception of acoustic distance and the possiblity of altering it with equalization. Updated August 18, 2014. Corrected some misspellings and grammar, improved some wording, and completed footnote.
Decibels November 21, 2014. The calculation and use of decibels in audio.
Noise Shaping Music April 3, 2015. DSD-like coding inside PCM digital audio content increases its resolution. Updated May 27, 2015. Corrected equations 2 and 3 making pole only dependent on b₁; the a₀ coefficient only affects gain. Updated July 1, 2020 Added text to Final Remarks better clarifying why high bit resolution (32bit?) is desired in audio DACs...
Digital Phono Equalization June 6, 2015. Updated September 1, 2015. Added capability to digitally equalize a current-input preamplifier. Updated September 7, 2015. Added results of an actual test recording. Updated May 3, 2016. Added inverse RIAA functionality to software.
Turntable Geometry October 26, 2015. Theory, calculator, and protractor useful to setup your turntable's tonearm. October 26, 2015. Added a more precise statement about what software will print the protractor. October 29, 2015. Added explanation of overhang to the end of the theory section. Updated November 14, 2015. Added |φ_err/r| graph to calculator to give feedback that calculations are correct.
Dual-slope Integrator January 16, 2016. Reduce high frequency amplifier distortion.
Lossy Compression February 27, 2016. How does compressed audio like mp3 work and what effect does it have on sound? Updated February 29, 2016. Added time anomalies to Analysis of sound effect
Butterworth Filter Synthesis November 18, 2016. Updated November 25, 2016. Added highpass bode plot and example of calculation of pole angles and Qs.
Chebychev Filter Synthesis December 31, 2016.
State Variable Tone Control July 14, 2017.

Application

Line Level Class A Power Supply Updated March 11, 2010. Corrected for improper g_fs presumptions.
Low Noise 2-Stage All JFET Phono Preamp Updated July 2, 2010. SPICE verified. Recalculated with 48V power supply and RIAA standard gain.
A Linear Logarithmic Volume Control September 29, 2010.
Low-noise Hybrid Op-amp/Discrete Phono Preamp October 29, 2010. SPICE verified. Desire discrete output buffer to add neutral euphony to nearly distortionless op-amp preamp. Updated October 29, 2010 Improved visibility of graphs. Updated October 30, 2010 Added links to semiconductor datasheets in parts list. Move class-a bias to connect to positive supply, and verify no operational changes.
Cascode Selector November 17, 2010. SPICE verified. Audiophile-grade semiconductor selector for input or other switching. Updated November 27, 2010. Added power supply recommendations and a schematic for an LED indicator.
Cascode Phono Preamplifiers May 3, 2011. SPICE verified. Capacitively coupled cascode enables an easily adjustable single-stage preamp. Updated March 3, 2012 Added transfer error curve analysis for both circuits.
One-Bend Amplifier March 14, 2012. Part 2: Improving important details of a current-feedback amplifier.
One-Bend Amplifier June 6, 2012. Part 3: Modified circuit adds a predriver stage.
Floating Source-follower Regulator July 7, 2012. One-Bend Amplifier Part 4: Hum injected in stage 2 of amplifier required the design of a useful general purpose voltage regulator. Updated July 8, 2012. Added comment about the MOSFET's limited hum suppression capability after equation 11.
Warp Filter September 22, 2012. Highpass notch filtereliminates dangerous LP warp signals.
DAC Cascode December 1, 2012. Analog DAC circuit designed with one BJT. Updated December 2, 2012. Added text recalculating a new C4 value for the second circuit under load. Updated December 7, 2012 Correcting SPICE model error changed distortion results somewhat. Reworded statement about useful DACs to indicate that the AD1955 will require an NPN design. Added paragraph on the interpretation of the datasheet. Updated January 1, 2013. Added an NPN design and analysis based on the AD1955. Updated January 2, 2013. Changed schematics to show how unused DAC outputs should be terminated.
Voice Control October 26, 2013. Circuit enables adjustable euphonic control.
Distortion Grapher March 5, 2015. Circuit enables distortion error to be graphed.
One-Bend Amplifier August 20, 2016. Part 4: Improvements include lower hum
Sealed-box Speaker Equalizer January 14, 2017 Part 1: Chebychev design methods allow the design of speaker equalizer. Updated January 14, 2017 Added missing last curly brace not copied with program and added mention of use of SPICE Opus. Updated January 14, 2017 Added input for user to input his own C1/C2 choice to program
Sealed-box Speaker Equalizer March 18, 2017 Part 2: Design of equalizer with n-channel JFETs. Updated March 19, 2017. Corrected incorrect filenames in program use instructions and added a brief paragraph on buffer design. Updated March 21, 2017. Added section Determining speaker parameters.
Input/Output Bypass Board February 6, 2018.
One-Bend Amplifier May 15, 2018. Part 5: Set bias for class B/AB and evaluate results.
DIY Mogami Speaker Cables July 5, 2022. Coaxial speaker cables improve the sound of my stereo.
DIY Power Conditioning April 19, 2024. Add an X capacitor and then a ferrite bead to a surge protector for RFI suppression.
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Downloads

CD Exerciser – Improve your CD player with a homemade test disk April 20, 2009
Op Amp Noise Calculator Updated January 17, 2011. Added considerable new program functionality including accounting for flicker noise.
Phono Termination Calculations and Calculator Details in Theory above.
FETCurve June 26, 2011. A FET parameter calculator. Updated May 31, 2012. Added SPICE verification. Updated program to version 1.1.0 to flag alias error and to show k_n for transconductance factor to avoid confusion with SPICE parameter KP. Updated June 2, 2012. Updated program to version 1.2.0 adding input checking for numeric entries. Immediatedly released version 1.2.1 to allow negative number entry.
Turntable Geometry Theory, calculator, and protractor useful to setup your turntable's tonearm. Details in Theory above.

Obsolete

JFET Phono Preamp - Active Inductor Example Updated March 11, 2010. Corrected for improper g_fs presumptions.
Low-Noise JFET Phono Preamp - Active Inductor Example This is a redesign using LSK170 JFETs on the input. Updated March 11, 2010 Corrected for improper g_fs presumptions.

External Links

Real Stereo program sponsored by TNT-Audio

Affordable$$Audio Internet audio magazine archives, just merged into HiFi Zine below (subjectivist, some advertising)
Audiophilia Internet audio magazine (subjectivist, some advertising)
AudioWorld Web Directory This website has reverted to an Audio Web Directory again for now.
AudioXpress Website of print audio magazine emphasizing DIY (subjectivist/objectivist, some articles on website)
Enjoy the Music Internet audio magazine (subjectivist, some advertising)
High-end Audio The personal audio website of Arthur Salvatore (subjectivist, no advertising).
High Fidelity Internet audio magazine (subjectivist, some advertising)
Hi-Fi Choice Website of print audio magazine (subjectivist/objectivist, some articles on website)
Hi-Fi News & Record Review Website of print audio magazine (subjectivist, some articles on website)
HiFi Zine Independent internet audio magazine (philosophy?, some non-audio ads)
Positive Feedback Internet audio magazine (subjectivist, some advertising)
Six Moons Internet audio magazine (subjectivist, some advertising)
SoundStage! HiFi Internet audio magazine (subjectivist, some advertising)
Stereophile Website of print audio magazine (subjectivist, some articles on website)
Stereo Times Internet audio magazine (subjectivist, some advertising)
TNT-Audio Independent internet audio magazine (subjectivist, no advertising)
Ultra High Fidelity Magazine Website of print audio magazine (subjectivist, interesting general hifi reading on website, but no magazine articles)