How MXR Distortion + Reinvented Drive Circuits | Gain Appreciation

[@ScienceofLoud]

The first 1,000 people to use the link will get a 1 month free trial of Skillshare: skl.sh/csguitars1122 MXR Distortion + : Thomann - thmn.to/thoprod/162223?offid=1&affid=367 Sweetwater - imp.i114863.net/Gjv192 Utilising then new stable op amp technology which miniaturised a transistor amplifier circuit into a tiny chip, the MXR Distortion + is arguably the first pedal to ditch fuzz in preference of sounding like a valve amp. This video contains paid promotion from Skillshare More details on how CSGuitars implements product promotion - www.csguitars.co.uk/disclosure Timecodes: 00:00 - Introduction 00:49 - LM741 & Op Amp History 02:17 - Variable Gain, Non Inverting Amplifier 03:23 - Germanium Clipping Diodes 04:10 - Gain & Clipping Sound Examples with Scope Traces 04:48 - Distortion Circuit in full 06:04 - Skillshare Sponsor segment 07:26 - Op Amp Slew Rate & Filtering 09:20 - Sonic Summary of Distortion + 09:40 - Sound Examples 11:43 - Conclusion Resources: LM741 Datasheet - www.mit.edu/~6.301/LM741.pdf Op Amp Slew Rate Frequency calculator - www.learningaboutelectronics.com/Articles/Slew-rate-calculator.php Op Amp Gain calculator - www.learningaboutelectronics.com/Articles/Op-amp-gain-calculator.php Low Pass Filter Frequency calculator - www.learningaboutelectronics.com/Articles/Low-pass-filter-calculator.php Get 15% OFF unique and colourful Mr Gugu clothing with discount code 'CSGuitars' - mrgugu.com/ #distortion #opamp #skillshare More from CSGuitars: Gain access to exclusive content at: www.patreon.com/csguitars Join CSGuitars Discord - discord.gg/csguitars Buy CSGuitars Merchandise - www.csguitars.co.uk/store Website - www.csguitars.co.uk Contact - [e-mail] ____________________________________________________________________ *Description contains affiliate links. Purchasing using one of these links will generate a small commission for CSGuitars at no additional cost to you.*

[@nacuda9]

MXR is currently working on RR version. They looked and analized it from his pedal board.

[@ScienceofLoud]

@@nacuda9 and I'm 100% certain the result of that "analysis" will be to sand the identification numbers off a standard IC, claim it is a super rare NOS that made all the tone happen, then jack up the price 300%

[@ophhate]

@@ScienceofLoud damn last time i saw you, you had long hair in your room damn time really does fly

[@KamiKuzi]

I really like your scientific approach to explaining guitar electronics. No snake oil salesman here. Also I just love the sound of the scottish accent!!! Greetings from a german electrical engineer drummer guitarist guy. 🤣🤘

[@andrewmorgan1640]

One of the best graphical explanations of clipping I have seen Colin, love it!

[@markhammer643]

1) Actually, the diodes are not absolutely necessary to achieve clipping, although the distortion will be much more evident with them. Keep in mind that, with a +9V supply, the 741 will only be able to "swing" about +/-3500mv in each direction. Assuming an input signal of +/-100mv (hitting a power chord), it only takes a gain of 35x to hit the headroom ceiling of the chip. And since the gain of the circuit can be adjusted up to 214x, much of the range of gain settings achieve clipping *within* the chip. On DIY forums, people would often ask "I lifted the diodes to get a clean boost but I still get clipping. How come?". THAT'S why. My own contention is that, by virtue of this propensity to clip *within* the 741, before any introduction of diodes clipping, makes the circuit functionally a *dual-clipper*; i.e., it clips once in the chip, and the chip output gets clipped again by the diodes. That double-clipping is part of what results in a more level and compressed sound. Pristine clean amplification, followed by diode clipping wouldn't provide that. 2) The manner in which gain is adjusted in a non-inverting op-amp has different implications. When gain is adjusted via feedback resistance, as it is in a Tube Screamer or Rat, in tandem with a capacitor in parallel, treble is rolled off as gain is increased. In contrast, when gain is varied using "ground leg" resistance, as it is in the Dist+, the *bass* is rolled off as gain is increased. In the case of the Dist+, the rolloff begins around 720hz at maximum gain, as you've illustrated. In the case of the Dist+, my hunch is that this had two consequences, whether anticipated by the designers or not. One is that de-accentuation of bass at higher gains achieved a more strident tone with searing mids and highs. So kind of an automatic tone adjustment for free. The second implication is that, with fewer options for hum-rejecting pickups than we currently enjoy, providing *less* gain for content in the range of 50/60hz hum, and its multiples, would result in less of what you didn't want at higher volumes. If a person has all their hum under control and would like more oomph to their tone, the cure is identical to what many have done with Tube Screamers and derivative designs; namely increase the vale of the .047uf (47nf) capacitor between the Gain pot and ground. A value of 100-220nf will restore a lot of the guts missing from higher-gain settings. 3) Given when it started appearing, my sense is that MXR tried to achieve two things with the Dist+. At its lower gain range, the goal was to yield a sort of clean booster. This would transition into distortion as you turned up the gain. To achieve that, the unit used a reverse-log gain pot, that would provide the high resistances needed for low gain, but quickly transition out of that to lower resistances. 4) Over the course of several issues, people found that it was difficult to achieve any appreciable volume, unless one dimed the gain control. This appears to have been the result of using a less-than-called-for Volume pot value of 10k. Keep in mind that, with the 10k resistor just ahead of the diodes, a 10k volume pot behaved like it was a 20k volume pot that could never be turned above 50%. Later issues adopted use of higher value volume pots of 50k or even 100k, allowing for volume levels well above bypass volume, even when gain was not up full. 5) The DOD250 uses what is essentially the same circuit as the Distortion+, but employs silicon, rather than germanium, diodes. This raises the clipping threshold, yielding an output which is perhaps not quite as severely clipped, but is easily much louder. 6) The rolloff provided by the cap you've designated as C6 (in parallel with the diodes), really does diddley squat that's actually audible; especially given just how many speakers begin their rolloff around 6khz. For a warmer sound, one can supplement the stock 1nf (.001uf) capacitor with another 2.2nf (.0022uf), tacked onto the pads on the copper side of the board. This will lower the rolloff (still rather shallow) down to just under 5khz, for noticeably less fizz without losing one tooth's worth of bite.

[@toby8261]

I hope that one day I can reach your level of understanding of audio electronics. Awesome write up

[@markhammer643]

@@toby8261 Thanks. Much appreciated. And trust me, you will.

[@gpdaelemans]

Ahhh... The '741'! The building block of many college electronics circuits exam questions... What memories!

[@ScienceofLoud]

A true classic

[@TheSchane]

So much knowledge 🧠. Thank you for making such awesome videos. You really have a knack for making sense of things and relaying them in no-nonsense terms. If I could have had someone like you teaching in my school as a younger person it would have turned out far better for me. Big up!

[@ikestoddard2458]

Best distortion explanation I have ever seen. Great job! “Smells vintage!” was glorious! I am an electrical engineer (class of ‘76!) who had just encountered op amps as they entered university curricula. Your explanation spoke directly to my brain. Grateful! Thank you, Colin!

[@Amp_Expert]

According to the Wampler Distortion Plus MODS page one can find, Brain says changing the 4.7k to 1k and the 4n7 to .22uF increases gain but does not change the high frequency response! At 3:16 in, it shows you the formula for Gain = 1+(1M/(gain know resistance+resistor)), which is 1+(1000000/0+4700) = 214 = +46dB. Changing the 4k7 to 1k would result in = 1+(1000000/0+1000) = 1,000! So about a 5x increase in distortion. Not sure what that equates to dB, but > +46dB (I think it's like 60dB)!!

[@apojomovsky]

Man, I just discovered your channel. It's full of information explained in luxury of detail. Also your graphs are amazing. Keep it up!

[@gringogreen4719]

Thank you for mentioning similar pedals. I already have a ProCo Rat on my board that has been modified by Alchemy Audio. So I will keep with that. So I will mention that my bias of modern pedal trends may have gotten the best of me. When I go back and find a tone/sound/timbre I like (70s UK Punk/Post Punk/Alternative Rock/Indie) I go down a rabbit hole to see how they got that sound. I am looming for a boutique or rare pedal when I look at what those players used. Well 99.99% of the time its a classic, basic pedal... Be it MXR, DOD, Boss, or any other OG manufacturers, it's amazing how spending a bit more time on amp settings, basic effects, and using your volume and tone can achieve such wide ranging differences in tone.😳 One player I will point out is Daniel Ash from Bauhaus. Listen to his tone in that band. His main guitar was just a Fender Telecaster and mainly standard pedals and a good amp. Still his tone and sonically how it does the lifting in those recordings is amazing!😳👍✨

[@jye_24]

The MXR Distortion + Still Reigns Champion till this day because they were the first to Master Distortion. Every Pedal Company After just Copied them and Never Matched MXR. It's no Coincidence the Distortion + Is one of the Few Popular known Overdrive/Distortion Pedals to Only Consist of an Output and Gain Dial. Pure Guitar Pedal Mastery!

[@TealScarab]

Thoroughly enjoyed this video! I’d love to see one on the pedal circuit that came after fuzzboxes but before hard clipping distortion: Treble Boosters!! Dallas Rangemaster and the Hornsby-Skewes really shaped the sound of proto-metal greats Black Sabbath and Deep Purple respectively.

[@ScienceofLoud]

I recently got myself a Treble Booster from SharpEnd FX, I think a history and circuit analysis video on that would be a great idea.

[@TealScarab]

@@ScienceofLoud Yes!! If I may make one addition, it’s to mention the fella who gave Brian May the idea to use the treble booster in the first place: Rory Gallagher!!

[@nicoguarini28]

Judas Priest also used Treble boosters to scorch the earth.

[@LarsonGuitarPlayer]

This was probably the best explanation of how an overdrive circuit in a pedal works! I tried a Distorsion+ in the late seventies, didn't like it and never looked back. Discovered the DOD250 a year ago and found out it was a clone of the MXR, so I had to try one. LOVE IT! So, 45 years later I have the 250, the + and the RAT on my board. 😂

[@andersonpessoa1671]

This video made me understand why the 741 integrated circuit is so often used in so many distortion pedal designs. To date, I've only played with DIY transistorized pedal projects using BCs 548 and 549C. Thanks for the video 😁👍

[@michaelnewell9662]

thanks for showing the o'scope display - it really helped!

[@michaelcottle6270]

Fantastic video - this is the type of content you produce that I enjoy more than any other. I love the explainations of how the circuit works.

[@ChrisEck13]

Hey Colin, I just watched Rhett Shull's video on the DS-1 yesterday. In the video Josh Scott says that the original Boss DS-1 actually did not use an op-amp, but transistors. Later versions do use an op-amp but the circuit was designed to sound the same as the original non op-amp circuit.

[@gretinaveo1125]

Always blows my mind how so much of distortion is just "MAKE IT LOUDER"

[@ScienceofLoud]

Yup, make it louder and force it to clip. That's all it is.

[@xdoctorblindx]

Such a fantastic explanation of how these components work - not just excellent information for guitarists, but a masterclass in science communication!

[@jstrat121]

My 1982 dist + blew the opamp…in 1983.We replaced it and taped a penny to the top of it as a heat sink……been chuuging perfectly ever since…40+years later

[@kevinwhite6176]

One of the things I've wanted for a long time is explanations as to why different fuzz, overdrive, and distortion pedals sound the way they do. You do that, and it's super amazing.

[@jaminjimlp]

I had an original one way back in the early 80's switched to an ART SGX200 in the 90's and got rid of it and a JCM 800 LOL and recently I found on "General Guitar Gadgets" a Distortion+ that you can build your self for quite cheap and comes with all parts.... so for Christmas I got one and a Klon Klone to build!!! just having my boxes powder coated before I build them ... can't wait!!! I think thats right up your ally bro... One thing I also found was the "Baby Will" and the "Super Lite II" their circuits based on the 1974x Marsh.. Your my new favorite channel!!!

[@subjectt.change6599]

Thank you for the opamp lesson. A better understanding of the tech inside one’s pedals allows one to utilize it in a more musical way. Knowing this kind of stuff makes pedal stacking a much more creative process. Again, thank you.

[@lordviewer7305]

Man this video and the visual are top notch. Plus the analysis of one of my favorites gain pedals. Your channel is getting more and more incredible and informative.

[@dantorres1070]

nothing but compliments on this excellent explaination of MXR's at-the-rime tech development of the imiginatuon needed to create such a solution to the problem. and, yes it was the breakthrough we, the rockers of the time jumped on. I ran it through a gigantic Ampeg V4( 8 x 12") stack to achieve "the sound'-

[@celecoxibnonsteroidal5659]

Best guitar channel hands down. I love this!!!!!

[@keithzibrat5721]

I found your channel from following 3x3 customs and the great guitar build off. I saw your flying v and checked you out. Loved your guitar build and started following you. Love your vids and info. Got me into building a few clone pedals from kits, then an 18 watt marshal amp. I'm hooked on it and thanks for boosting the interest! I've made a Frankenstein "tribute" guitar and waiting for parts for a strat guitar. Best things for you my friend!

[@nyxmugen]

Ahhh Yes! My first analog pedal. I regretfully traded it for another pedal I thought I needed at that time but fortunately got another one last year. I keep coming back to this pedal because aside from it sounding good, it just works well with how I play.

[@stepans2167]

It's a brilliant pedal! It's the first one I've bought as well. The only drawback is it's lacking in volume with low gain :(

[@angusorvid8840]

The MXR Distortion + was the first clear distortion pedal. It's not hot by today's standards but running it through a cranked Marshall still sets off some real fireworks. I got an old 70s era MXR when I got my first Marshall, a JMP stack, in the mid 80s. To this day it's one of the best tones I've ever had. It was a very clear, cutting distortion, very much in the vein of Randy Rhoads.

[@DrHouse-zs9eb]

That's really a professional explanation! 👌

[@DarkItachi1]

best guitar videos on the Tube they should pay you more!

[@KainzMusic]

I love these techy historic educational videos! Thanks for posting it!

[@snarfusmaximus]

The first pedal I ever built was a close relative of the Distortion +, the DOD Overdrive 250. This would have been around 1995 when I was 18, with parts I had lying around and a scrap bit of veroboard. I still have it and it sounds great. I love the 741.

[@mrcoatsworth429]

This pedal is a big part of the early Iron Maiden sound.

[@ScienceofLoud]

MXR sold a lot of them and they would have been in the hands of a great many bands who would eventually break through to success in the 80s.

[@lucamoqi]

Let's not forget Randy Rhoads!

[@sim0n17]

I think Dave's big MXR tone came from a MXR Micro Amp, no?

[@mrcoatsworth429]

@@sim0n17 the micro amp is just a level booster. It doesn't really have a "sound". Dave used the Distortion + for the first 5 albums.

[@sim0n17]

@@mrcoatsworth429 gotcha - I really didn't research this, I just remembered him as using a micro amp back in the day. But even though it is a "just" boost, it does change the tone of the amp when pushing the front end of the pre-amp section of a tube amp.

[@TLMuse]

Thumbs up! Really nice analysis, esp. covering the implications of the 741's low slew rate. Classy presentation, too. Easily earns my subscription. -Tom

[@chrispfeifer7628]

MCR was my very first distortion pedal, along with a Big Muff, it's all I had for a couple of years

[@sim0n17]

hard to beat the Rat IMHO, but this Distortion + is a fun pedal for some creamy old school distortion -- nice video, thank you sir!

[@alrecks619]

The Rat is just so versatile ngl.

[@pauldncn1]

Colin thanks that was the best explanation of distortion ever!! Might just buy one.. !!

[@lorddjungelskog903]

This video has now made me want one of these

[@bober770]

That's what this video was made for

[@mrcoatsworth429]

@@bober770 not really. It's more educational than advertising. The MXR is just historically significant.

[@_oe_o_e_]

I forgot how badly i “needed” one of these. Also cool of guitar youtube talkiing about classic pedals all of a sudden

[@pqsk]

Wow. I just bought the distortion+ a few years back. I figured the circuits were different because I had bought a boss ds1 and the circuits were clearly different from my old one from way back in the 90s. I returned that one and bought a used one, but the distortion+ I only played a few times. My buddy had one around that same time. I don’t remember too much the sound. Anyways great video

[@Alfredo78666]

The poweeerrrrrrrrrr of the transistoorrrrrrrrrrrr

[@tonyy.8852]

I thought this video would be about the DS1w, but I never knew that this is such an awesome pedal!!

[@ChrisHopkinsBass]

It’s actually a development of a Dan Armstrong circuit (the blue clipper). The schematics are almost identical apart from not having distortion or volume controls

[@burresseffects]

Dude if you ever make it to Nashville we need to hit some guitar shops together.

[@justincrumpton1210]

Have you ever played an HH Ic100 before ? That’s a UK 🇬🇧 amp from the early 70s that’s all 741 amp based and was one of the first guitar amps to use it as far as I know. That circuit was a fixed gain with it switch so it was either on or off and included an active EQ circuit which was so ahead of it’s time. Maybe the vox defiant and conquerer from 68 used them too but I’m not sure would have to look at the schematic

[@vivekmehta5172]

I wish to correct a common misconception You said at one place in your video The Opamp alone would have just been a clean boost were it not for the germanium clipping diodes Earlier you calculated the gain of the Opamp to be maximum around 200x Suppose a guitar signal is 1Vp, we are then asking the Opamp to create 200vp at it's output. That is impossible to do with a 9V power supply. Hence the Opamp "rail saturates" This creates distortion! So for most of the travel of the gain pot, distortion is being created at two places, 1. at Opamp due to saturation 2. Hard Clipping diodes Many reviewers forget or don't appreciate the point that the Opamp rail saturated. It is easy to test though. If we remove the clipping diodes, we will still hear clipping (due to Opamp rail saturation) the

[@rustystove8410]

I saw a video where the guy said the left knob simulates the power amp section and the right knob simulates the preamp section I use it was transistor amps it is sounds really nice.

[@moliver_xxii]

8:50 "filtering inside the feedback"... yes there is a capacitor forming a filter in the feedback loop of the distorsion amplifier however i'm wondering if it is not to remove the input offset voltage of the opamp out of the equation. short explanation: at x100 gain (+40dB) a continuous 5mV offset becomes 0.5V which is around the same level as a clipping diode... i think the filtering is just a bonus, but don't get me wrong IT CAN change the sound, and that is something i haven't checked.

[@An2oine]

Best video on how the clipping actually works on the pedal. What is that device that has the signal waves you used called?

[@kitevason-roopra9784]

Just discovered your channel, love your videos - in your opinion what're the best pedals for emulating an amplifiers distortion?

[@gregmize01]

SUBSCRIBED! WHAT A GREAT CHANNEL!🎸🎸🎸🎸

[@toms5951]

One of my favorite flea market finds was a '79 Distortion + for $30. I have to be extremely careful using it now because I've had to resolder the battery connection twice now. I've thought about retiring it and buying a modern one but have been afraid of the two sounding completely different.

[@PooNinja]

I love my lil yella dist + such a sweet saturation

[@eddiejr540]

I had one of the originals when I was a kid…it use to eat up batteries so I had my handyman neighbor rig it up to take a power supply…I would run that into an old JCM 800 and rock out…we played Maiden, Scorpions and lots of Rush…I have no idea what happened to that pedal…. ahh, good times 😎

[@hadleymanmusic]

The next step up after this pedal was the ratt with its spec higher grade transistors. But Glen says its in the low watt speakers

[@raoulselten9480]

comment for the algorythm. video is really really good :)

[@kennyjohnson336]

I have the Whirlwind Gold Box (Dist + Clone) and love it.

[@kennethnielsen3864]

Nice video, thanks for sharing.

[@jcwm01]

This was my first distortion pedal back in '82. I used it into a clean tube amp boosted with a Boss SD-1 to approximate large tube amp distortion. I still have one on my board as my primary lead boost into distorted Marshalls. It creates smooth singing lead lines with tons of sustain used this way. Love this video Colin! Always nice to learn the inner workings of classic designs. Cheers! John

[@Traumglanz]

Awesome channel.

[@backlom]

Looks like you’ve taken a leaf 🍃 from the 42 guy with the new wardrobe! It works!

[@TheMerc1950]

Algorithm fodder. Great Video.

[@luther_beckett]

I've got an original MXR. Pretty sure it's first year. Pretty beat. Chunks of nobs missing. Paint wore. Modded to take a power supply and needs a potentiometer. Was working great until the pot went bad. How much is it worth?

[@otimizandogeral]

my pedal is a distortion III, it spent a long time with the battery inside, which broke and stopped turning on the distortion. the two states (on and off) the led appears lit, while the switch when in the off state, the true by pass works, but when in the state that should be on, it does not output any sound. I will try to change the diode and capacitor to see if it comes back to life. I am sad...

[@Hneel65]

I played a lot with 741's in the 80's, building preamps and distortion circuits. Perhaps in hindsight I should have started a pedal company.

[@STRATMAN1969]

I don't have a mxr but I have a clone in the V shaped enclosure of a Vox Distortion which is a clone of a Guya tone which in turn is a clone of the Distortion+

[@DJZKOfficial]

I wonder now if it will sound the same if i decided to build one for myself.

[@ScienceofLoud]

A really easy beginner circuit with plenty of room to change or expand to taste. But the core circuit is unlikely to sound much different if you keep all the component values the same.

[@krauz111]

masterclass

[@mcswordfish]

CS Guitars: The Shirt of Loud 😜

[@FranciscoBravo-bm2om]

Qué buen video 😃

[@LinkWrayisGod]

Teenage Kicks!

[@jsullivan2112]

Always loved what other people did with them, especially Alex on Permanent Waves and Movie Pictures, but my Mark IV doesn't seem to like them for some reason. So I had to return it. I was sad.

[@geordiedog1749]

No Husked Du mentions!! Tut tut.

[@AutismRocksOfficial]

Jazz Hands! Love your shirt

[@ivangil-silva2044]

The new version sounds thin and what I can sonically guess is that the low mid is less loud and the harmonic differential is not even enough.

[@HalfFlat832]

Orange stripy triangle!!

[@russiangoose7053]

Do you have any favorite Distortion+ Mods? This is one of my favorite pedals of all time thanks to the Doyle of the Misfits using them during the 80's into his 3 Ampeg V4 heads

[@m.a.6478]

Ah, yes, the good old 741. When I learned how it works during my apprenticeship it was already outdated for most applications. Little I knew what it was actually useful for!

[@gandalfilgrigio97]

what's the name of the first song? i definitely heard it before but can't remember the name

[@pcollenyt3683]

Does it ONLY sound good with the OUTPUT at MAX ?

[@tylerdean980]

Is it possible to build a guitar pedal with a microcontroller like a pi zero or arduino?

[@googaboogaloo]

I prefer the dod250. It feels cleaner/brighter to me.

[@ScienceofLoud]

Just about the only difference between the DOD250 and the Dist+ are the clipping diodes. DOD uses silicon diodes which have a higher forward voltage, clipping the signal at a higher amplitude - resulting in the 'cleaner' sound.

[@googaboogaloo]

@@ScienceofLoud when I made my DOD clone I socketed the diodes just so I can see how big of a difference and it’s crazy how much diodes can change the sound.

[@CastToVoid]

The more parchment colored your Distortion+ is, the better it sounds

[@1972LittleC]

In the beginning I thought you were going to play the intro to China Grove...

[@RedroomStudios]

thought it sounded great with the Les Paul, but crap with the tele.

[@martinclayton7260]

The science of loud ( tee shirts)!

[@MeatyController]

Colin's shirt is louder than any amp any of us will ever play though

[@greevar]

Colin! Did you see Jim Lill's video in which he built an amp that copies several mainstream amps with a breadboard and solid state pedals?

[@ScienceofLoud]

I did and it was equally as lacking in any actual science and overloaded with false conclusions as his other videos are.

[@YourWifesBoyfriend]

@@ScienceofLoud Examples?

[@ScienceofLoud]

For one to design an effective experiment which will yield valid results one must firstly be educated on the fundamentals of the subject and have defined the parameters they are testing for. Jim unfortunately does neither, his 'experiments' are blind stabs in the dark - the reason that most of them come back as inconclusive is because he isn't performing the correct test to yield the result he wants - but because he has no idea what he's doing he isn't aware of the flawed process and concludes falsely that something must have no impact or purpose. Even the times when he lands on the correct answer he draws incorrect conclusions on the cause. Having even the most basic understanding of proper scientific process will make watching his videos a frustrating experience, as he time and again makes confused arguments and arrives at grand revelations which would have been self apparent from the outset if he'd done any research at all. Highly entertaining and well put together content - he's great at making an engaging video- but of absolutely no scientific or objective merit whatsoever.

[@YourWifesBoyfriend]

@@ScienceofLoud Examples?

[@ScienceofLoud]

Ok, let's take a couple of specific examples from the 'Where does the Tone come from in an Amplifier' video: Firstly he never properly defines the parameter he's investigating on, he talks about 'tone' and trying to hear a difference, but doesn't define what precisely he's listening for. There are many sonic elements of an amplifier you could listen and test for: frequency response, dynamic response, headroom, distortion character and so on. When testing the rectifier he openly admits he doesn't know what it is or what it does, so it's impossible to design a test for it. He cites two words from forum discussions "spongy" in relation to valve rectifiers and "tight" in relation to solid state - he doesn't investigate what these mean. He then strums a couple of chords in an A/B and leads the viewer to form the conclusion that rectifiers make no difference - a test which is NEVER going to yield a useful result because what he should be investigating here is dynamic response, by playing something with high dynamic range and sharp transients it would expose the volume drop which results in the 'spongy' response from a valve rectifier. A couple of lightly strummed chords aren't testing for what the differences between rectifiers are. Later in the video it becomes clear what he IS listening for when he finally arrives at the EQ circuit and he has this massive revelation that the part of the circuit responsible for the frequency response of the amp is the thing changing the frequency response - that would have been self apparent had he any understanding of circuits. So he's actually looking for an EQ difference, which of course you aren't going to hear with rectifiers or different valve topologies - but he falsely concludes (or at the very least leads the viewer to conclude) that those non-frequency altering elements have no impact over how the amp sounds - which is wrong. Had he tested for dynamic response with rectifiers, or for headroom and gain character with valves he'd have found that these too have a dramatic impact over the sound and performance quality of the amp - OR if he'd defined at the outset that he was only listening for frequency response then he wouldn't be writing off important parts of an amplifier as essentially unimportant and the data could have been useful. And possibly the most egregious part of the whole thing comes in the recurring joke of "I'm just a performer, I don't know anything about circuits" - well maybe you should learn something about them before taking to the internet trying to disprove them? The statement is there as a device to make him relatable to the average viewer, someone just like you that you can trust - not one of these so called experts - and he then goes and 'does his own research' and encourages you to conclude that the scientists, engineers, and designers - people with degrees and doctorates in the field of electronics - who have been making these things for decades are in fact lying to you about it all. It's sadly misinformation being broadcast under the guise of science and sensationalised to make you think some 'truth' is being exposed, when in reality it's just someone who doesn't understand how things work reaching the wrong conclusions.

[@JosephGallagher]

Dunno why I liked the waveform clipping shape as distortion increased

[@fabiogarofalo6685]

does anyone know the value of R9 on the pcb? I've got one with this resistor burnt and I'd like to replace. Thanks!

[@ScienceofLoud]

This pedal has gone through a number of changes over the years, so the component numbering is different depending on the version you have. Since it's burned out, I'd take an educated guess that it's one of the two 1Mohm resistors that form the voltage divider inside the power section. Being the first component in line with the power socket, if it's been provided too much voltage at some point, it would be the first part to go. It should be sitting beside another resistor (possibly labelled R8), if it is still intact measure its resistance, as it should be the same as the one beside it.

[@fabiogarofalo6685]

@@ScienceofLoud I thought about the 1Mohm resistor too, or that associated with the voltage divider, since the line goes straight to pin 7 on the opamp. But as far as I can see from images of other boards R8 and R9 have different values. Also in the same revision as mine (I have revision D of the board, but the GREEN PCB) they have different color codes. I wrote to MXR to know more about but still waiting for the response. how sad... should I throw away my D+?

[@LemonTanko]

I'm confused, is this a livestream? I have never waited for a video "release" on KZbin

[@ScienceofLoud]

This is a 'Premiere', a feature where the video is scheduled to initially release as a live broadcast where we all get to watch and chat in real time. After the initial live playthrough is finished, the video automatically becomes a standard VOD.

[@mickavoidant4780]

Do digital distortions and overdrives, such as the Boss BB-1X have an op-amp at the heart?

[@ScienceofLoud]

Digital implies that the signal is being processed by software to produce the sound. There will still be op amps involved, namely to amplify the signal level after the signal is converted back to analogue, but any digital distortion effect is using software to mimic the result of an opamp + clipping circuit.

[@mickavoidant4780]

@@ScienceofLoud Thank you for the swift answer

[@hadleymanmusic]

Hadley smash square wave. Must be sine and positive

[@overvieweffect9034]

I'm learning about mosfets in my electronics class, and this video made me wonder why they aren't used more often in guitar pedals, since they are so tiny and efficient. As such I wonder if there's a legitimate reason for that, or if it's just guitar industry doing as usual with inovation

[@ScienceofLoud]

Mosfets are more commonly used for power amplification, which is why they aren't in pedals all that much. Op amps, jfets, and bipolar transistors are more common for class A preamp circuits

[@overvieweffect9034]

@@ScienceofLoud indeed, thank you, Colin!

[@Patrick-857]

Mosfets are essentially solid state relays. They are excellent at switching on and off at really high frequencies which is why they get used in power electronics, like motor controllers, inverters, switch mode power supplies and of course D class amplifiers. A D class amp is essentially an inverter that makes audio waveforms instead of a 50 or 60 hz sine wave. A switch mode power supply is an inverter that doesn't change the pulse width at 50 cycles a second, as it aims to create a constant DC voltage out of a high frequency AC waveform from the mosfets. They all do the same thing with the DC supply, which is switch it on and off at high frequency and vary the pulse width to create a different effective voltage on the output, either to create a low frequency waveform, or a constant DC voltage. JFETS on the other hand, can almost exactly mimic the behavior of a vacuum tube. I personally would be interested on seeing what a mosfet could do if abused to create distortion, but I suspect their extremely fast switching is probably not what we're looking for in guitar tone. Perhaps they could be made to clip a signal from an op amp with a suitable circuit that sets a certain threshold for the MOSFET to switch on and dump the signal to ground, resulting in extremely sharp clipping. I wonder....

[@Patrick-857]

Just did some research, and yes, MOSFETs can be used for clipping, I've yet to hear it, but it's definitely something that gets done, in much the same way as diodes are used. Edit: they aren't used for clipping usually, but it's actually quite common to use them in cascading gain stages much like any other transistor based fuzz or distortion. Apparently more tube-like just like JFETs.

[@alphanumeric1529]

You've had some major capital infusion?

[@grinnerschic]

Feel like that shirt would have cost a fortune due to the complexity of the pattern

[@CliffeDuffield]

I recognise the riff around 11:28, but can't remember what it's from... Any help so I can learn it?

[@ScienceofLoud]

Crazy Train - Ozzy Osbourne

[@CliffeDuffield]

Sweet, I can now play that riff from Crazy Train!

[@low_e_music]

Not enough gain, too much mids, no Slayer. PASS! Haha, seriously though, great explanation of the pedal. Kind of want one now.

[@RozsaAmplificationLLC]

Great video with thorough explanation, but the approach for the Rhoads-type of tone is all wrong and modern! At about 11:21 in, the volume it turned up all the way, then gain applied which is a more modern technique and more focused on tightening up the bottom-end and chug. That is completely different than back in the day! Back then, you turn up the GAIN, not volume, and in Rhoads case, that is at 100%, then turn the volume up to the level of when the pedal is off, so no change in amplitude!!