The myth of "gain"... and it's relation to "clipping" 

We've needed a video like this for a long time! Great info

I used to pick up Mexican radio stations with my MXR Distortion+.

To get the idea that gain doesn't always equal distortion think of the gain knob on a PA mixer. You need to turn up the gain to get a stronger signal but it stays clean until the signal is too strong and starts clipping the preamp. I think guitarists associate gain and distortion because guitar preamps are designed to clip right away as opposed to mic preamps which are designed to have a lot of clean headroom.

I love how awesome a 30-second, thrown together circuit sounds from this wizard!! Electric Wizard that is.

So, most pedals intended to produce additional harmonic content are powered by 9Vdc. In most instances where op-amps are used, the maximum amount of "voltage swing" permitted by that supply, and the op-amp characteristics, is about +/-3.5V AC. That is, exceeding a signal amplitude of +/-3.5V will clip because the power supply cannot make the signal increase any more. So far, so good. The typical guitar pickup will produce very brief peaks of maybe 1 volt at pick attack, and settle down to well under 100mv thereafter, humbuckers and overwound types a little more, and underwound and normal single-coils a little less. But let's take our benchmark of 50mv, for argument's sake, since that's what you'll get picking a single string hard. How much does 50mv go into +/-3.5V? Seventy times. That is, multiply a pretty normal picked note by 70x, and you've run out of clean headroom on a 9V supply. Strum a chord on an HB-equipped guitar, and you run out of headroom with gains of 40x or so. Many overdrive pedals apply gains of hundreds, and some (e.g., the Proco Rat) go into the thousands. Although they often use diodes to do some of the "dirty work", what you hear is often a composite of the clipping produced by the chips running out of headroom, PLUS whatever the diodes are doing. One principle I have been touting for darn near 15 years is what I like to call "proximity to clip" (PTC). That is, the electronic distance between the point at which clipping will occur, and the current signal level. The intensity of the clipping is partly a function of that distance. PTC can be reduced (brought closer) by increasing gain applied to the signal, OR by bringing the threshold of clipping lower. Perhaps more importantly, since guitar notes *decay* with time, the closer the PTC, the longer the portion of the note's entire lifespan will be clipping and adding harmonic content. What we often call "fuzz" is essentially a circuit that keeps the PTC very small for a long time, such that the buzz continues long after the initial pick attack and well into the string's actual decay. By making the clipping threshold very low, we can get distortion with very little gain. The poster child for this is the "Black Ice" passive clipping circuit, that uses Schottky diodes, whose clipping threshold is so low that these units are installed in the guitar itself, with absolutely NO gain applied. Conversely, if one was to use *four* green LEDs for clipping, you'd have to apply so much gain to get them to clip (their threshold would be about +/-4V) that what you'd hear is really mostly headroom limitations of the chip, rather than any clipping from the LEDs. So, it's not JUST "gain". It's how close a given amount of gain gets your signal to the clipping threshold, given how the pedal is powered, what you're using for clipping, and whether you want the clipping to be confined to only the pick attack, or last for more of the note's lifespan.

for some thing that took 30 secounds to put together it sounds KILLER! that fuzz like tone was crazy good.

I think people just use the term gain to express how dirty the tone is. I'm an engineer, I did electronics at university. The thing is, it doesn't matter if people understand what it really is as all they care about is weather it's dirty or clean. With that said, great video. Informative to folks that are interested in what's going on behind the green curtain.

I'm compiling a bunch of your videos cuz I'm getting a breadboard+parts for my birthday, so excited! Thanks for the info!

Please Mr. Wampler. keep these awesome videos coming. Whole lot of respect good sir!! I really like learning about this kind of guitar electronic awesomeness

Thanks for doing videos like this, please do more! It would be interesting to see an oscilloscope view of an A440 sine curve with the different clipping modes applied.

I was just about to email you about this! So glad I found YOU explaining it before I did.

Mr. Wampler, your videos are just amazing!!! I'm waiting to receive my breadboard and some fancy parts to test some ideas about the clipping pedals, maybe stack two 4558c ic and some filtering sound decent. I can't wait to test it!!!!

This is a much needed video. Gain is a measurable quantity, an is purely the ratio of the output signal level to the input signal level. The "high gain" sound adjective was the start of the problem. My guess is that it gained prominence from the Carlos Santana sound created by the Boogie amps that Randall Smith was creating from Fender amps by adding an additional preamp tube. Technically, that adds gain, but when the signal level is already at the maximum, it doesn't get any louder. It does add sustain (quiet parts are louder) and increase the harmonic content of the signal from the clipping and compression. So that compressed, distortion sound that Santana is famous for, became associated with "high gain." That trend continued in the 1980s when the rock and metal players started playing through amps, and racks, that had multiple preamp gain stages. It would be interesting to hear the three versions through a Fender Twin or JC-120. Something that has a ton of headroom. Even on the clean "no diodes" version, there is some distortion/grit/crunch on the attack with the Fender Deluxe.

Brian Wampler: National Treasure and a big ol' Nerd.

Hey Brian great video. That amp on “clean” sounded fantastic even before you introduced any of the variables.

Wow Brian, your playing is getting really good... love your vids.

Great video mate. I'm not an electronics expert or an amazing guitarist but this is info I read about years ago ,pre internet in something called books. We used to change the clipping character of our amps to a degree by swapping ECC83 valves for 12AX7 etc . It's a great advantage to any player to understand this stuff ,wether we are talking valve amps or our solid state pedals . Thanks for adding some real information to the so called "Information super highway" 👍😉🎸

Awesome video! Very informative and practical. Thank you sir

7:49 " share with your friends, family, goats, etc" quite saddened to see that babysitters have been left out.... but I enjoy your videos too much so I won't even mention the babysitter thing! ;-) Thanks a bunch for all your insights, wisdom and unique perspective! -dan

Thank you for sharing. Always a welcome sight

A perfect example of how gain doesn't equal distortion is the fuzz face. it has less gain than a tube screamer, but it sounds nastier and rougher, so most people would say that it has more gain, even though that isn't the case.

Loved it. Would've liked some more explanation on the breakup caused by the gain control as opposed to the clipping. Thanks!

listening to this through a stereo pair of Blackstar fly amps..they sound great as powered monitors (by the way). Even on this fairly new amp they have have a "gain" pot, and a volume... and an OD button...when the Overdrive is engaged you dial up up the "gain" pot to get more saturated clipping...pretty sure a lot of the confusion people have about gain comes from mislabelling of solid state amps over many years.

Thanks for another crash course in frequency and tone of learning a lot

just adding a bit to this awesome demo. Running a voltage through a diode junction always costs you some voltage. The standard is 0.7V per junction. So putting more diodes into a circuit will keep cutting your voltage and can actually re-attenuate so you can re-amplify and add stages. FWIW, I took advantage of the junction drops in a different way: I made myself a "Universal Music Power Supply" out of a PC power supply which comes with 12v and 5v standard(powers all my 12v synth modules, LED lights on my rig, and USB modules) but didn't have 9v for my pedals. So I strung together 4 rectifier diodes backwards so they just conducted (they can handle lots of current vs signal diodes) and dropped the voltage down to 9.2v which is perfect for my pedals. ps, just jumper the green wire on the main motherboard connector to any of the black wires to spoof the power supply into thinking it is connected so that it turns on.

Great info, as always. And your tone is absolutely drool-worthy.

Thanks for sharing. These kind of videos are quite informative. Which op amp do you use? TL072? Thanks a lot. The new video about changing components is also quite nice. Thanks.

This is cool. Wish I knew more about the inner workings of pedals.

Super interesting. Love this video! About to go on a deep dive on your channel

Brian, thanks for another really useful video. I plan to buy my first Wampler pedal, what do you recommend. I mostly love overdrive and distortion pedals, my current favourite being an older customer shop Fulltone Full-Drive 2. For gigs I use a Fender Blues Deluxe set fairly clean.

Great video as always! What kind of pickups are installed in this Tele? They sound just awesome!

I always share your great videos with my chickens.

Your pedals are just absolutely amazing. I have your Tumnus deluxe set as always on clean to give the guitar more depth. I also have your Dracarys for really high gain, it is amazing!! But I need a good overdrive. Which pedal can I get that has the same footprint as the others and with jacks on top of the enclosure, that would give me more of that in between overdrive sound? Thanks again for all you do.

Yaaaam....dat sound goooood!!!! What amp / cab / monitor are you hooked into? I liked the bright and the dark :D

I was thinking more of the gain control on a tube amp, cranking that up in reference to gain, or saturation. However the OP amp did simulate that well.

Great video Brian! One question on this subject: when you have an amp like a Fender Hotrod, for example, where you have a drive channel and a switch for "more drive" (that's literally the name of the switch in this case), does it have something to do with this soft clipping/hard clipping thing you just explained? Thanks

ACKCHUALLY the schematic for "hard" clipping you provided contains a variant of a soft clipping circuit. That R1k before the diodes is the distinction. With such resistor, the circuit exploits internal resistances of clipping diodes and forms a voltage divider with them, making the circuit merely reduce the voltage past certain level instead of shunting it to the ground completely, similarly to how feedback clipping circuit reduces the gain to unity and not zero when the signal reaches certain level... If I'm understanding that correctly at least. Actually, I think I'm not. I only know that Rod Elliott has a wonderful article on the topic of soft clipping from which I memorized only the practical implications.

Love your videos. To my ears the op amp clipping sounded best, followed by the soft clipping.

I Love your videos and your products, so Thank you!. I have been playing guitar since I was 9 and now I'm 49. Our band plays all different types of cover music + originals. Rock, pop, country. R&b and blues. I have been in Love with the Randall type of overdrive/distortion for all of my life, unlike Marshall type and others to me its smooth and not brittle sounding the way I use it. Currently I have the Dime D-100 amp that I love I use a EQ pedal in the clean channel to brighten it up and add mids, ( very fenderish) but it is not on overdrive channel, its a Randall RG-100 with more options and only made for a short time. "we are not a metal band I don't us it as a high gain amp. My question is, what other types of pedals or amps tube or solid state are out there that can give me that type of sound? Also in your mind what kind of sound is it, and have you ever messed with that type of overdrive or circuit? I have had and tried Alot of stuff of the years and its all Marshall/Fender/Mesa sounds. I just love the little different and still versatile things that still sound great. Thank you!!!!

And the light goes on... thanks again!

Thanks for this video!!! Very helpful

Using LED as clipping diodes also makes some interesting sounds , much more non linear and softer and also back to back in odd combinations. I one of my gain sections in My Peavey classic vt and chained a few leds back to back and a different amount in the opposite direction and experimented and tuned in what i liked. Was a cheap mod and made a huge difference harmonically.

This discussion may have gone better with some wave form examples. We engineers get, it but most guitar players are artists, not engineers. Love your products!

Thanks Brian. Great video.

Thanks for the info, but I am more confused. I am sure one of the lengthy comments may have my answer, but before I read all those, I will ask: 1. What would the 3 different circuits be called ie. what type of pedal? 2. What is gain, and what does an amp mean when it says "High Gain". I always assumed it meant distortion. 3. I understand clipping as frequencies above/below a certain amplitude being cut, not passed, thus somewhat 'distorting' the waveform. Is that correct? Is that distortion? 4. What is soft vs hard clipping? It appears to refer to when in the circuit the diodes are placed, but I don't get why they are called hard and soft. 5. Can someone run down what components in a pedal make it a boost, preamp, overdrive, distortion, or fuzz pedal? 6. What does a typical 'distortion/overdrive/dirty' channel on an amplifier do to the signal? Since is always has a 'gain' knob, I assume it at least adds an opamp stage. 7. Which pots in the schematic are the gain, volume and tone? I am asking this because buying pedals is VERY confusing with overwhelming numbers of options and terminology. If I know what I want to modify (by understanding the questions I asked) , then I have a better chance at buying the right pedal.

This was very informative thankyou!

Hi mr brian , you equator is awesome.

From an engineering point of view all these words are rather subjective. Something some companies once invented. A bit like vibrato vs tremolo that's being mixed a lot. Technically distortion is just how much changes in it's harmonic content. There is linear and non-linear distortion. The right way in this sense is calling (hard or soft) clipping. In fact a distortion pedal is nothing more than a compressor/limiter in extreme form. So maybe calling it the limiting ratio would be a better name. But I guess it doesn't sound as catchy

Please Mr Brian, use a subtitle. English is not my first language, but every video that you uploaded was my favorite, i need more extra vocabulary to understand what are you saying about. 🙏🏻

Very good description of hard vs. soft clipping. A related topic I would be interested in hearing you discuss is the difference between pre-amp distortion passed onto the power tubes compared with preamps under the clipping threshold but the power amp tubes pushed beyond theirs. I remember Dickey Betts explaining that it was the power tubes on his 100 watt Marshall (50 watt for Duane) that gave the Allman Brothers Band their signature guitar tone (at admittedly massive volume levels). But I wonder if there are any combinations of lower powered output tubes and higher threshold preamp ones that might yield that particular type of clipping at lower sound levels? Or is it more of a sonic illusion with the difference being more perception than reality?

Thanks for another heads up.

Great video!! I would like to have a low-gain hard-clipping pedal on my pedalboard, a sort of “hard-clipping overdrive”. Could I modify a Guv’nor just to lower the overall gain? I love the way it clips (hard-clipping red leds), and the eq section. Is it as easy as to change some resistor values? Thanks!

Man, box this up and I'll buy it. Be sure to include the three different clipping options. Much obliged.

Good explanation... thanks

Hi Brian. There's seems to be some difference in the resulting EQ, between soft and hard clipping... More mid with soft, more scooped with hard. Am I right?? Does clipping style affects EQing? If so, do you use these differences when you design pedals? Thanks!

Man that overdrive circuit with the soft clipping sounded really freaking good

Soft clipping with the drive up sounded awesome!

So, you demonstrated the difference between soft and hard clipping. My question is, what if you have both in the same circuit...? Would it be an uncontrollable mess or tonally unpleasant etc etc. I think these technical videos are great, being a lifelong tinkerer and professional electrical fixer of things... Cheers.

Hi Brian, would you be willing to talk about the best type of clipping when it comes to bass guitars? There’s so many OD’s that sound horrible and I don’t necessarily like clean blends at all. I have to say that I got a TS9 recently and did the stinkfoot mod for bass and the pedal sounds great with bass. No loss of low end at all. There is still a slight mid hump even with the gain all the way down but the point is symmetrical clipping seems to sound best to my ears. Thoughts? And thank you for all you do!

I'm curious; if you were to stack multiple soft clipping pedals would the resulting distortion be still technically considered "soft" clipping, or would it have crossed over into hard clipping? In other words is it the type of circuit or circuit topology that determines whether it is properly called soft or hard clipping, or is merely a matter of a "degree" of distortion heard at the end that makes us consider it hard or soft?

+Wampler Pedals; Excellent video, thx! Killer #breadboarddirtbox tones!

I'm loving all of these tones. Could you just make this pedal available please?

GREAT video! i was wondering if you could tell me which IC was used in the video

i blended the distortion from a ts9's and a 15watt GM108 Behringer and a big muff pie, the ts9 and Behringer run in series and the big muff is in parallel with them, the two distortions playing side by side sound vary full. basically it sounds like a Revv G3 I just needs the sound level equalizer.

The very last test, when u took the diodes out. To me that sounded the best out of all. Can u tell me any pedals that do that particular thing? I just absolutely loved that sound. To me it sounded like the guitars actual signal was being idk the words. "Less processed, maybe?" It just sounded great to me & I would love to know about pedals that do that.

With a non-inverting soft-clip op-amp, when the diodes start conducting, the feedback path to the inverting terminal becomes like a wire, but with a DC voltage offset (the Vf of the diode). This (usually) reduces the op-amp gain and also causes the peaks of the signal to follow the input signal, which gives that clean-plus-dirty thing you hear in this video and with a lot of TS-type pedals. The diode thresholds are usually low enough to avoid actual op-amp clipping. Like Mark Hammer said below, if you used 4 green LEDs (two series pairs back-to-back) in the feedback loop, you might get op-amp clipping before that wire-plus-DC-offset thing happens, but that's an extreme case.

Hard clipping feels more amp like... thanks Brian!

Hey Brian... What in the circuit makes more or a heavier distortion? Like the difference between an overdrive or light distortion vs super heavy distortion pedal? Is there additional diodes or different diode values? Thanks

That guitar into that amp sounds so good.

Great video!

What amp and pickups are you running? I love that tone

I prefer referring to "harmonic saturation" because I find that's what we're really talking about. Clipping causes the harmonic saturation and increasing gain against the volume ceiling causes that clipping, which gives you harmonic saturation. But what people mean when they talk about the tone of the gain or wanting more gain or different gain is usually harmonic saturation-the "dirt."

So to recap: Gain is the increase in the signal from the pre-amp, to the power amp and "clipping" is the effect that adding diodes to the circuit, does to the signal. Btw, why does the tone change significantly at 4:18, after you reach to the controls?

You should have thrown a comparator circuit in there. Those are fun :)

After watching this, I now think of all overdrive, distortion, etc. pedals as clipping pedals of various degrees.

Gain = difference in amplitude between the input and output signal. (you can have a crispy clean amp with TONS of gain. More gain even then the metalist of metal amps....) Distortion = any input waveform which is altered in shape (not scale). Either by tube saturation, diode clipping, transistor clipping. Even a phaser can distort your sound. In theory, your can have a distorted sound, which has a lower amplitude/output signal compared to the input signal. That is how confusing the mixup is to many people. Even after this video.... I'm sorry. You told it in a much too complicated way. You can tell by the reactions people posted...

Clipper ship T-shirt, too. Nice touch!

This is completely new to me. I like the no diode sound by a lot. What pedal, amp, or amp settings are no diode?

Clipping will add volume because of the distortion generated I agree. However any input stage can be overloaded (as in the guitar amp input stage), so pure linear gain without diodes can also cause clipping if the input gain is set high enough. As someone mentioned, clipping can be induced by reducing or restricting the voltage supplies of amplifiers, op amps and otherwise. By the way the input gain of the amplifier is actually fixed most of the time. The so-called gain control simply attenuates the input signal going into it. Boosters boost it. In the case of valve amp input stages the type of distortion they generate is very attractive to the ear, more so than op amps with diodes in their negative feedback loop or out of it (soft or hard). Both can cause distortion. If your amp is a valve amp one way (the valve amp way) is way nicer sounding than the other op amp way (which is why power attenuators are sold).

that's it ... THANKS Brian

could you do the same thing with an oscilloscope connected? always appreciate your knowledge mr wampler

Brian, I’m an aspiring electronics developer. I wanna do the stuff you do. Idk if you’ve talked about it before, but how did you get there? What kind of education did you get and what’s a good starting point for someone who is really just starting out?

Whatever that last one was my favorite it was nice and dark sounding. :)

I have a question , a technician told me once that most modern high distortion tube amps, like EVH 5150, and other similar style amps , are not really tube distortion but some other type of clipping, and the tubes just basically buffer, or shape the tone, and that there’s no way you can get tubes to sound like that on there own. That they are just pretty much big fancy distortion boxes, and not true tube amps. How true is that statement, can you talk about this in another episode perhaps. Or can any of you provide an answer to my question. Thanks.

Hi there! When pushing a plexi thats already crunchy, which type of pedal do you recommend for a liquid compressed lead tone? ts or klon type or something else? My timmy is too transparant for that.Thanks!!

I think the confusion is mostly in the different way the term is used in electronics versus by musicians. In electronics "gain" is just how much the amplitude increases compared to the original signal. If you put 1 volt in and get 2 volts out that's a gain factor of 2. But guitarists know that if you increase the gain enough eventually something is going to clip, and if you increase the gain you get more clipping, so they just forget about the clipping and call it "gain". But yeah, as you show different circuits produce different amounts and types of clipping at the same gain.

When amps came out with master volumes, people would turn up the preamp gain and it would overdrive the circuit and clip/distort, so they began equating gain with distortion. Not technically correct because gain is just the amount an amplifier component increases the level of the signal, but it is understandable people mistake it for distortion.

Great information. May I ask you a question? Why is my amp constantly picking up AM radio? How do I stop this?

I'm wondering how difficult it would be to make a drive circuit with both soft&hard clippers but not the way you already guessed. I'm wondering if one could put one diode in the feedback of the opamp and the other to ground after the opamp probably with a resistor in series. Or two in each but with resistance on only one diode per pair. How would someone calculate the resistance or type of diode. If need not be opamp either, only fun and different.

That Tele sounds great!

Well a clipped signal is what causes or what you hear and perceive as distortion. This happens when you amplify the signal causing gain to increase. Which can be done by raising volume at certain point or gain directly

Thanks for doing that , makes it easier to understand .... and are you a sailor? I like the T shirt...I am one too :)

Maybe you should make a pedal that changes the diodes and clipping settings and call it the hair cut or the Barbour or something? Either way that bread board setup sounds pretty damn good !

Thought the hard clipping with full gain and diodes in was killer! Especially for the tele bridge position. What pedal do you make that sounds like this?

So what happens when a plexi style circuit is dimed n gets that tube saturation sound that we all love.... What's clipping there? Everything? I know with my dirty shirley when master is dimed gain is dimed, the speaker preamp n power amp is distorting all together to make the sound of rock n roll..... But.....is this different then clipping?

Wow this stuff is over my head! lol I was just thinking though, you always hear about pedals being copied and cloned and whatever, my question is how different are any of the distortion/overdrive/fuzz pedals circuits on the market? I've read that many pedals out there are tube screamer variants and that the original ibanez overdrive (can't remember if it was a tubescreamer or their earlier overdrive pedals) was a copy of the boss od-1 except that it added a tone control and changed the clipping type. If all distortion/overdrive/fuzz pedals are doing basically the same thing then how different could the given circuits really be?

:-B Great playing, thanks.

I've always preferred the gain achieved by pushing the amp with the pedal as it kinda marries the 2 devices together to create one sound. Whereas if if the amp is completely clean and the pedal is at unity volume, you are relying on the pedal to do all the dirt which to me sounds more like an amp with a devices connected to it. That's why I think every distortion/overdrive pedal should have plenty of volume available. One reason why jhs pedals sound really great with the volume turned up.

That diode-less circuit sounded righteous. Honestly would love to see that as a Wampler pedal.

I like the whole no-nonsense thing :)