When I built pedals back in the late 80s, I had a lot of success with using different diodes such as OA79s (Germanium) to induce softer clipping, which introduces more even order harmonics than silicon which is primarily odd order. So much fun was had for such a simple circuit. Crazy things ensued beyond that!
@AmRad Podcast Good point on the BE junction. Germanium are probably way less common these days than they were "back then". I've got a big bunch of weird old diodes that I picked up on a whim for some low wattage "terrible as possible blues" valve amp idea I had. I've never tried LEDs, however I'd imagine that there's SO many things that are possible with the availability of different clipping options. I'd better not talk myself into projects, because I'm sure you know how that might get....! Oh no...here it comes...
@@jim9930 There's all sorts of weird and wonderful combinations that can be achieved, definitely. Making them usable across a range is quite a trick, as they easily become very on-off. I recall RA Penfold publishing a nice dynamic distortion transposing input characteristics onto the distorted signal, that sounded great in principle.
Awesome! Before electronics school (and the Internet) I tried to reverse-engineer the foot switch circuit from a cheap Boss pedal and got discouraged when I saw that it went to a bunch of transistors. The flip-flop transistor arrangement looked scary so I gave up. I never did revisit it after school. I was super happy to see you touched on it here. The DS-1 has a little cap across the clipping diodes. Maybe to kill some of the over 20kHz harmonics so they don't cause intermodulation distortion? Would a little demo of harmonics (say, of a proper overdriven pair of 6L6 tubes compared to a distortion pedal output) be something people would find interesting? That was another thing I really wanted to try if I ever got an audio-frequency spectrum analyzer.
Epic! Few days ago I did clone of Electro Harmonics OD GLOVE which is totally outstanding. In this instead cliiping diodes used N-MOSFET 2N7002. The sounds of this is simply amazing. I had never guess it could be so difference and so fantastic.
@@waynegram8907 Probably its a main difference. I can't put link and image here yt immediatelly delete post. You can check in Derek thread on the element14, which hi shared in describe. So yes I guess 90% work is done by Mosfets. Be precise I did little clone of GLOVE, now I inspired in the other distortion I'll try change 4148 diodes on to this mosfets :D Difference is total, pleasse check any GLOVE test on the YT. It got a very low self noices level, very wide distortion set from normal guitar by little overdrive/overdrive/distortion/hard distortion to fuzz at the end. And all of this have very warm(rich) TUBE AMPLIFIER SOUNDS.
One modification to the hard clipping circuit that we rarely see is a tail resistor on the diodes. Considering how simple the mod is, I'm surprised that I still haven't tried it myself, but I've thought about using something like a 100 ohm pot in that position to vary the "hardness" of the clipping, from full-on clipping to something more akin to the plate saturation of an overdriven Class AB valve output stage. I've also considered experimenting with separate tail resistors to get asymmetrical distortion similar to those small Class A valve amps that many of the earlier rock guitarists used in the recording studio.
@AmRad Podcast Thanks for the nice reply! I actually came up with the idea when I was looking for ways to simulate germanium diodes, and the results were all tail resistors...but not actually implemented in hardware, just simulated in SPICE.
This is great, it's not something I've looked at before but it's inspired me to look at making one for a friend who loves his guitars, thank you. Can you make the schematic available to download please, it would be easier to view than pausing the screen?
Maybe I'm mixed up, but this looks more like a fuzz box with its clipping diodes. A distortion pedal overdrives an amplifier. It's hard to tell with the 1000s of different types on the market.
Talking about Jfets, a few days ago I've build a simple buffer using a jfet and another using a opamp. Using any of them, the pedal before the buffers makes a big pop noise when I switch on the pedal. I can not find a real solution on it, does somebody has an answer to solve it?. I have build a three jfet stages overdrive and the sound is really good.
ELEMENT14, How do the SLEWRATE of the op amp add more distortion and it also alters changes the frequency response? The slewrate is just the time interval it takes for the op amp to take the input signal to the output signal its just a timing issue in nanoseconds. I don't know why slewrate will add more distortion and change the frequency response of the input signal on the input pin to the op amp, can you explain more in a video lesson ?
The slew rate is the maximum speed that the voltage can change at the output (not the stage delay of the opamp). For the 741, it's about 0.5V/μs. It has the effect of turning large signal outputs of any shape into triangle waves because the output simply cannot change any faster than a ramp going up or down at 0.5V/μs. The higher the frequency and the larger the signal, the more attenuated the triangle wave becomes.
@@RexxSchneider Distortion meaning taking a sinewave input the op amps slewrate will cause the sinewave input to be a triangle waveform on the output, but this is called waveshaping not distortion this is a misinformation term. I think he meant to say waveshaping not distortion. Slewrate is the speed/time interval it takes for the op amps output voltage to change. If you look the the op amps input pin and output pin using a 2 channel Oscope there won't Delay in time but there will be a shift of the instantaneous voltage point won't be at the same point as the input voltage to the output voltage because they will be at different points in the instantaneous voltages
@@waynegram8907 The definition of distortion is simply altering a signal. You are mistaken to think of it as waveshaping. We reserve the term "waveshaping" for signal processing that we deliberately introduce to produce a desired effect, and normally we control the extent and type of the distortion that we add. In the case of slew-rate limiting, distortion occurs in an uncontrolled manner, which really doesn't fit the concept of waveshaping. So, no, he _did_ mean to say distortion, because we have no control over the distortion introduced by an opamp that is slew-rate limited. I've already told you what slew rate means, and it *does not* mean a "time interval". The clue is in the word "rate". It represents the maximum rate of change of the output signal, and I've already told you what the typical slew rate for a 741 is. Slew rate has *nothing* to do with the time it takes for a signal to propagate from the input to the output of an opamp. Please try to get that through your head. If I use a scope to compare input and output signals of a non-inverting audio opamp, the only difference will be the amplitude of the signals, depending on the gain. The phase shift is completely negligible at audio frequencies. There will *not* be _"a shift of the instantaneous voltage point won't be at the same point as the input voltage to the output voltage because they will be at different points in the instantaneous voltages"._ Wherever you've got that nonsense from, please stop reading it before you embarrass yourself any further.
The 741 typically requires 80nA of dc bias current into its non-inverting input. Where is that coming from? Are you relying on leakage current from C5 to supply that, lol? It's a sad comment on how much the art of designing with discrete transistors has declined, but it's just not cost-effective to use JFETs like the 2N5458 any more. The part itself is close to obsolete, and each one costs about £1 from Mouser. In contrast the TL074, a quad JFET-input opamp, costs about £0.60 which would replace the input and output buffers as well as the 741 with a spare opamp to play with. The TL074 needs 6mA from ±5V supplies, while the 741 needs ±10V at 3mA to stay within spec (it will work on lower supplies like a 9V battery, but it's not guaranteed). A CD4016 quad switch (£0.50) could replace the routing switches (2N5458) for dry/wet and have two spare switches to play with. It's fun to see folks still designing around discrete transistors, but for JFETs, their days are probably numbered. Some time, you might like to try the effects you can get when you have 4 high impedance opamps and 4 solid-state switches to design with, for little more than the cost of a single 2N5458. Thanks for the video, it was trip down memory lane.
Yes, the schematic has to be wrong. In fact you can see from the video at 9:37 there is a blue lead from pin 3 to a resistor that goes to the rail, which is different from the schematic.
When I built pedals back in the late 80s, I had a lot of success with using different diodes such as OA79s (Germanium) to induce softer clipping, which introduces more even order harmonics than silicon which is primarily odd order. So much fun was had for such a simple circuit. Crazy things ensued beyond that!
@AmRad Podcast Good point on the BE junction. Germanium are probably way less common these days than they were "back then". I've got a big bunch of weird old diodes that I picked up on a whim for some low wattage "terrible as possible blues" valve amp idea I had. I've never tried LEDs, however I'd imagine that there's SO many things that are possible with the availability of different clipping options. I'd better not talk myself into projects, because I'm sure you know how that might get....! Oh no...here it comes...
@@jim9930 There's all sorts of weird and wonderful combinations that can be achieved, definitely. Making them usable across a range is quite a trick, as they easily become very on-off. I recall RA Penfold publishing a nice dynamic distortion transposing input characteristics onto the distorted signal, that sounded great in principle.
I am interested in revisiting the flip-flop.
Nice and warm sounding distortion !!
I think you got the explanation of the tone control backwards. When you increase the value of the potmeter the cutoff frequency goes down.
That was cool. I love a nice jackson. I have 2 from when I was younger playing the technical death metal but now I'm a prog guy
Awesome! Before electronics school (and the Internet) I tried to reverse-engineer the foot switch circuit from a cheap Boss pedal and got discouraged when I saw that it went to a bunch of transistors. The flip-flop transistor arrangement looked scary so I gave up. I never did revisit it after school. I was super happy to see you touched on it here.
The DS-1 has a little cap across the clipping diodes. Maybe to kill some of the over 20kHz harmonics so they don't cause intermodulation distortion?
Would a little demo of harmonics (say, of a proper overdriven pair of 6L6 tubes compared to a distortion pedal output) be something people would find interesting? That was another thing I really wanted to try if I ever got an audio-frequency spectrum analyzer.
Epic! Few days ago I did clone of Electro Harmonics OD GLOVE which is totally outstanding. In this instead cliiping diodes used N-MOSFET 2N7002. The sounds of this is simply amazing. I had never guess it could be so difference and so fantastic.
So you removed the clipping diodes and Used N Mosfet 2N7002, and what did it do differently?
@@waynegram8907 Probably its a main difference. I can't put link and image here yt immediatelly delete post. You can check in Derek thread on the element14, which hi shared in describe. So yes I guess 90% work is done by Mosfets. Be precise I did little clone of GLOVE, now I inspired in the other distortion I'll try change 4148 diodes on to this mosfets :D Difference is total, pleasse check any GLOVE test on the YT. It got a very low self noices level, very wide distortion set from normal guitar by little overdrive/overdrive/distortion/hard distortion to fuzz at the end. And all of this have very warm(rich) TUBE AMPLIFIER SOUNDS.
One modification to the hard clipping circuit that we rarely see is a tail resistor on the diodes. Considering how simple the mod is, I'm surprised that I still haven't tried it myself, but I've thought about using something like a 100 ohm pot in that position to vary the "hardness" of the clipping, from full-on clipping to something more akin to the plate saturation of an overdriven Class AB valve output stage. I've also considered experimenting with separate tail resistors to get asymmetrical distortion similar to those small Class A valve amps that many of the earlier rock guitarists used in the recording studio.
@AmRad Podcast Thanks for the nice reply! I actually came up with the idea when I was looking for ways to simulate germanium diodes, and the results were all tail resistors...but not actually implemented in hardware, just simulated in SPICE.
Nice chops man.
Straightforward, I must say.
This is great, it's not something I've looked at before but it's inspired me to look at making one for a friend who loves his guitars, thank you. Can you make the schematic available to download please, it would be easier to view than pausing the screen?
Very nice circuit analysis. Thanks.
Did you ever figure out why your fet analog switch setup was squealing? Would love to see what all happened with that.
This video Rocks!!
Maybe I'm mixed up, but this looks more like a fuzz box with its clipping diodes.
A distortion pedal overdrives an amplifier. It's hard to tell with the 1000s of different types on the market.
Oh now that is a project to give s try!
Talking about Jfets, a few days ago I've build a simple buffer using a jfet and another using a opamp. Using any of them, the pedal before the buffers makes a big pop noise when I switch on the pedal. I can not find a real solution on it, does somebody has an answer to solve it?. I have build a three jfet stages overdrive and the sound is really good.
Great video I got 1 question for you where do the .1uf caps from pins 4 and 7 go to it says mid on schematic?Thanks!!!
What about a pedal series, showing how other guitar effects are done?
What does capacitor C10 do?
ELEMENT14, How do the SLEWRATE of the op amp add more distortion and it also alters changes the frequency response? The slewrate is just the time interval it takes for the op amp to take the input signal to the output signal its just a timing issue in nanoseconds. I don't know why slewrate will add more distortion and change the frequency response of the input signal on the input pin to the op amp, can you explain more in a video lesson ?
When you have low slew rate it take longer time to change the output voltage. So as the volumes increases the bandwidth drops.
The slew rate is the maximum speed that the voltage can change at the output (not the stage delay of the opamp). For the 741, it's about 0.5V/μs. It has the effect of turning large signal outputs of any shape into triangle waves because the output simply cannot change any faster than a ramp going up or down at 0.5V/μs. The higher the frequency and the larger the signal, the more attenuated the triangle wave becomes.
@@RexxSchneider Distortion meaning taking a sinewave input the op amps slewrate will cause the sinewave input to be a triangle waveform on the output, but this is called waveshaping not distortion this is a misinformation term. I think he meant to say waveshaping not distortion. Slewrate is the speed/time interval it takes for the op amps output voltage to change. If you look the the op amps input pin and output pin using a 2 channel Oscope there won't Delay in time but there will be a shift of the instantaneous voltage point won't be at the same point as the input voltage to the output voltage because they will be at different points in the instantaneous voltages
@@waynegram8907 The definition of distortion is simply altering a signal. You are mistaken to think of it as waveshaping. We reserve the term "waveshaping" for signal processing that we deliberately introduce to produce a desired effect, and normally we control the extent and type of the distortion that we add. In the case of slew-rate limiting, distortion occurs in an uncontrolled manner, which really doesn't fit the concept of waveshaping. So, no, he _did_ mean to say distortion, because we have no control over the distortion introduced by an opamp that is slew-rate limited.
I've already told you what slew rate means, and it *does not* mean a "time interval". The clue is in the word "rate". It represents the maximum rate of change of the output signal, and I've already told you what the typical slew rate for a 741 is.
Slew rate has *nothing* to do with the time it takes for a signal to propagate from the input to the output of an opamp. Please try to get that through your head. If I use a scope to compare input and output signals of a non-inverting audio opamp, the only difference will be the amplitude of the signals, depending on the gain. The phase shift is completely negligible at audio frequencies. There will *not* be _"a shift of the instantaneous voltage point won't be at the same point as the input voltage to the output voltage because they will be at different points in the instantaneous voltages"._ Wherever you've got that nonsense from, please stop reading it before you embarrass yourself any further.
Could I ask which software you use to draw the schematics?? Thanks! Amazing video
Nice!
AND you can shredd as well 😁
The 741 typically requires 80nA of dc bias current into its non-inverting input. Where is that coming from? Are you relying on leakage current from C5 to supply that, lol?
It's a sad comment on how much the art of designing with discrete transistors has declined, but it's just not cost-effective to use JFETs like the 2N5458 any more. The part itself is close to obsolete, and each one costs about £1 from Mouser. In contrast the TL074, a quad JFET-input opamp, costs about £0.60 which would replace the input and output buffers as well as the 741 with a spare opamp to play with. The TL074 needs 6mA from ±5V supplies, while the 741 needs ±10V at 3mA to stay within spec (it will work on lower supplies like a 9V battery, but it's not guaranteed). A CD4016 quad switch (£0.50) could replace the routing switches (2N5458) for dry/wet and have two spare switches to play with.
It's fun to see folks still designing around discrete transistors, but for JFETs, their days are probably numbered. Some time, you might like to try the effects you can get when you have 4 high impedance opamps and 4 solid-state switches to design with, for little more than the cost of a single 2N5458. Thanks for the video, it was trip down memory lane.
I came to ask the same for the input bias current.
Yes, the schematic has to be wrong. In fact you can see from the video at 9:37 there is a blue lead from pin 3 to a resistor that goes to the rail, which is different from the schematic.
Neat
Next make an analog delay pedal
how long did you figure this out?😂 It's quite complicated.
Frantone. Just saying.