How Diodes Work - In Guitar Gear

[@KleyDeJong]

A note of correction. At 10:43 I talk about stacking two diodes in series and how that affects the forward voltage. I have it backwards. Two diodes in series doubles the forward voltage rather than cutting it in half.

[@glennthrush7995]

This is remarkably helpful. I've recently started breadboarding, and so many tutorials simply describe the broad outcomes of inserting components of these circuits. I'm the kind of person who can't internalize these details without some sense of the why -- particularly your explanation of harmonics (which, in turn, got me thinking about how low-pass filters are used to limit the harmonic content and compress). In any event, keep on doing these -- there are people (meaning me) who are deriving a lot of benefits.... Cheers.

[@nowwhat1]

Hey Kley! Awesome video - these terms are used frequently in the guitar world (symmetrical clipping, asymmetrical clipping, compression, sustain, harmonics), but I don't think I've seen them explained and presented as clearly as you have done so here. Thank you - excellent job!!

[@KleyDeJong]

Thanks, glad it was helpful!

[@nu1ub]

This is exactly what I've been looking for for a long time. More such videos! :)

[@KleyDeJong]

Time stamps: 1:31 - Diode and electricity basics 4:00 - Forward Voltage 6:20 - How Diodes are used to clip a signal in an overdrive pedal 10:10 - Assymetrical clipping 11:40 - What symmetrical and assymetrical clipping do to an audio signal 17:25 - Diode clipping and compression / sustain 18:38 - Diode clipping and hard vs soft clipping

[@mrbigstuff6149]

Thanks for that and happy new year 2U.

[@S00PAMARIO]

Thanks for the vid. Recommend watching at 1.5x speed

[@chipsterb4946]

When you describe the clipping, you say that the diode dumps part of the signal to ground. There are (hard) clipping circuits that do exactly that; however, the Tube Screamer produces “soft” clipping by putting the diodes in a feedback loop. I am confused - is it a positive feedback loop or a negative feedback loop? IOW does the first op amp gain stage invert the voltage signal?

[@matyys19]

Thank you very much for your explanation! It was very helpful. However I have a question, sorry if it's dumb but I'm new to electronics. If the diode chops the sine wave, why sounds like a distortion and no like a compressor or limiter? Maybe I'm missing the point, I'll watch the video again anyway. Thank you again for sharing your knowledge!

[@daniilkolpakov2004]

Stumbled upon this video 3 years after it's out :) Sorry, you're mixing things up and misleading people. I'm not a professional elecronician myself, but still this is a public knowledge not some rocket science where you are mistaking, so easily verifiable. I've watched only up to 7:50 so sorry if you correct yourself afterwards. When you talk about the imaginary ideal diode deleting half of the waveform (that's called half-rectification) you must be referring to a chain where the signal goes in series through the diode. Then you say real diodes are having a forward voltage. Right. But when used in the same configuration, i.e. in series from the input to the output, it will not clip the way you show. Rather, you can imagine an area of 0-0.6V deleted (collapsed) and everything what's above it will drop -0.6V, so the lower part of the waveform will remain unaffected (correct), the upper one however will look as mostly flat line with only peaks of the original signal (which were above the 0.6V) raising above the zero line. When you show the overdrive cirquit, it's a soft clipping via op amp feedback loop. I think it's explained maybe on the very same website you are showing the image from. When an opamp is configured so that the output is connected straight to the negative input (marked -), it "copies" the input signal from the positive input (marked +) to the output (so called unity gain). When there's a resistive divider between the output and the ground, with the middle point connected to the negative input, the opamp will have some positive gain because part of the signal is going to the ground (and the opamp wants the + and - inputs to become of an equal voltage roughly speaking). In the softclip cirquit you've shown there are diodes which start to conduct when the output of the opamp is raising towards the diode forward voltage, "shifting" opamp configuration to the unity gain because the louder the signal gets the more diodes behave like a straight connection. Now this is quite hard to explain without showing pictures but I hope you'll note the effort and do some research ;)