Distortion

[GuitarLord66]

Hello

I found this schematic on the "diyaudio" forum and the guy who posted it "minion", in 2007, said he plays heavy metal and hardcore punk and this distortion suits the style perfectly, which is perfect for me since I'm in a hardcore metal/punk band. Also he states the orientation of the Transistors is reversed in the diagram....

Here's the diagram:


So even though some parts are hard to read I think I managed to draw up this schematic correctly?



What I don't understand is how distortion works, what this circuit is doing, whether this is actually a good design and how do the potentiometers work when there only at the input and outputs?

I intend to eventually learn how to build a full preamp, maybe with this circuit as its lead channel but for now this is my first audio based project so I should keep it at least a little simple

Any help would be greatly appreciated

EDIT: sorry if my schematic is hard to read... photobucket shrunk it down...

[DJPhil]

The transistor reversal thing means that if you use the transistors he suggests you need to flip them over so the curve is facing left. For various reasons, transistors don't follow a standard pinout. The three terminals of a bipolar transistor are Base, Collector, and Emitter, and the small transistors you'll probably be working with are labeled on the long flat side. Looking at the label, the pins on the transistors he used in his schematic are (left to right) CBE, and the 2N3904 is EBC. See how it just flips over? Sometimes it gets ugly.

I went looking for the original post for more context, and I found this one. For some reason, his more evolved idea seems to come before the first one. Sounds like this fella started tinkering too.

The first response to the first link above is an excellent start. That's Teemuk, and you should definitely download a copy of and read through his book. If you get stuck, check the pages in All About Circuits for reference. Teemuk's book has a section on clipping on page 250 that's a good place to start, and here's the AAC page on common emitter amplifiers.

Hope that helps.

[Jack1962]

well it will distort your sound I will say that , the first thing I will talk about is his choice of transistors (2n2222) although they are cheap and are fairly good general purpose transistors , they pretty much suck for quality audio applications. The second thing , this guy must just have ton's of diodes , he could have stop on the first stage  with them an it would have worked fine. The Third thing is the 15 volt supply voltage , it would have been much better to design around the standard 9 volts . However the circuit will work it would be a little harsh for my taste but would work , the pots the first one is for gain and the second(last one ) is for level .  It should however be a good project , enjoy the build.

                                                 Rock On

[GuitarLord66]

Thanks

I got heaps to read and do now, I just gotta buy myself a breadboard and some components and I can start trying some things

[GuitarLord66]

Sorry for another question but what kind of capacitors do I use? and whats the difference between capacitors? thanks

[DJPhil]

With questions like these, always try Wikipedia for a first stop (Capacitors). Capacitors have about a half dozen different properties that change depending on the type. The three types you might start with are ceramics for the small stuff (<1nF), electrolytic for the big stuff (1uF+), and pick your plastic (whatever's cheap) in the middle.

It helped me a lot when I first started to make a cheat sheet for caps so I could learn to convert pF/nF/uF and their markings (103, 474, etc.) back and forth. Beware, electrolytic and tantalum caps (and some others) have a polarity, so if you hook them up backwards (or exceed their voltage rating) they explode, violently enough to injure. The caps in your project are 100nF and 220nF, so any non-polar cap will be fine. There's reasons to be picky, but don't worry too much about it getting started. You can always pick up several types and play, but I think you'd be hard pressed to find much difference in this circuit.

Hope that helps.

[GuitarLord66]

Thank you And sorry for the dumb question I should have looked around better...

[GuitarLord66]

Another question sorry....

With that link you posted, Minion posted his pre amp, which you can see below:



Is this a full preamp? would I be able to use it to get a different sound? I'd be combining this with the distortion circuit and running it either straight into my Peavey Bandit 112 or into the Bandits power amp. Is it a decent amp? like are any of these DIY circuits going to compare to Peavey and Boss piece of equipment and give me a unique but still professional sounding sound? thanks again and remember I'm a newbie when it comes to audio electronics

[DJPhil]

Thank you  And sorry for the dumb question I should have looked around better...

You're most welcome. It's not a dumb question at all, and the whole story on capacitors is complicated and requires background knowledge to understand. It always helps to try your own research first, even if it fails miserably. I've always had the most luck getting help online when I can show that I've banged my face on a problem for a while and I'm stumped. Don't feel badly though, often it's hard to know just how to ask the right question.

Is this a full preamp? would I be able to use it to get a different sound? I'd be combining this with the distortion circuit and running it either straight into my Peavey Bandit 112 or into the Bandits power amp.

It looks like a simple preamp with a simple tone stack, and with a gain of 22 it should be fairly clean right up near it's utter limits. However, if you put a +/- 15Vp-p signal into the Bandit's input or effects return it'll sound horrible and may damage something, as it's probably designed to run at line level or lower. Whatever you try, start with low settings and work your way up. This preamp would likely sound different than the Bandit, mainly because the tone controls are likely to be different.

You might consider building your distortion circuit in such a way that you can simply insert it into the effects loop. If the Bandit has pre- and post effects EQ that's excellent, as both will have a noticeable effect on the sound of your distortion. If not, consider tacking a tone stack on your distortion circuit on whichever side needs it.

Is it a decent amp? like are any of these DIY circuits going to compare to Peavey and Boss piece of equipment and give me a unique but still professional sounding sound? thanks again and remember I'm a newbie when it comes to audio electronics

If you were building an amp from the ground up it'd be a great start. You could tinker with it and learn a lot, and build it to suit. DIY is all about experimenting to get what you want. Think of it as a large investment with the payoff being that you'll begin to understand how to make different tones. You can build an amp that's tougher than anything you can buy, fix your own rig, and design custom gear to get any sound you can find. I won't say it's always cheaper, but you have total control over the end result, the workmanship, and you'll eventually never have to pay someone to fix your stuff.

As for a professional sound? Depends on what you mean exactly. DIY gear won't sound worse than commercial gear without a reason. Don't like the tone? Tinker away. Too little/too much gain? That problem is usually solved by a single resistor. Distortion not sound right? You can make a dozen different distortion circuits in a weekend and stage a crunch off! The only limit is how much of yourself you'd like to invest. Many find it easier to pay for the gear and focus on the music, and there's nothing wrong with that. Keeps the technicians fed! It's not unheard of for big name musicians to have a technician at their back to help them find a new tone, or tinker with their distortion. Knowledge is power.

The commercially available amps out there are designed by folks a lot like the best of the DIY crowd, but they have different goals. They have to make it profitable, so sometimes they or their management have to leave out neat options, or necessary protections, or the proper parts! There's nothing inherently magical about a $5K amplifier, the designers are as much a slave to physics as we in the DIY crowd. The real magic, to me, is getting lots of people to pay $5K for a mediocre design made up of $250 worth of parts! There's a lot of hard sweat and real innovation in the commercial amp world, but it doesn't always get respect, and all to often amps or companies get more respect than they deserve.

Ok, finished ranting about the injustices of the music world. Sometimes I get a bit . . .   :loco

In all honesty, it's likely that the only way anyone ever gets a unique and professional sound is custom work, be it hardware or post production. By learning to tinker, you don't have to be rich or famous first!

Hope that helps. I got a bit gabby today.

[GuitarLord66]

Thanks heaps
I'm planning on making an order soon since all i got here at home is a bunch of resistors and LED's... lol.
I know I have been asking a lot but what extra values of transistors, capacitors, resistors, etc, should I buy to start "tinkering" with? I don't want to make an order and think, "I should have got some of those..."
Again, thank you so much you have been so much help

[DJPhil]

I know I have been asking a lot but what extra values of transistors, capacitors, resistors, etc, should I buy to start "tinkering" with? I don't want to make an order and think, "I should have got some of those..."

That's a tough question really. You'll always be saying, "I should have," it sort of comes with the territory! It really depends on your budget, as new parts assortments can be expensive. I get most of mine disassembling and scavenging old electronics that are on their way to the landfill anyway.

Welcome to the wonderful world of datasheets. Bookmark this. Any time you see a chip, diode, or part number you can start there and see if there's a datasheet for it. The passive components have sheets too, but you have to know part numbers or manufacturing identifiers. Use the hell out of this, and try to learn what the mysterious abbreviations and graphs mean. I'm not all the way there yet, but I've learned more from datasheets than any other single source.

Here's my take on start up parts.

Passive components
Resistors, Capacitors, and Inductors fit in here. You'll probably never have to use an inductor, and that's a good thing. These have a set of 'preferred values' called the E series. There's a company called Velleman who makes blister packs of resistors and capacitors in a few different series, and those can be a good way to stock up for the first time. I don't think you can buy direct from them, but lots of places resell the kits. You can use the Velleman part number to search around. Don't sweat tolerances too much yet, especially on capacitors. A big set of brand new 1% metal film resistors can eat into your starting budget.
Important! Learn how to use two or more caps and resistors in series and in parallel to get values you don't have handy and improve their matching (there are programs that help with this), it'll stretch an E3 cap set and an E12 resistor set to cover almost anything.

Diodes
I get heaps of these scavenging. You can divide them up into roughly three categories: rectifier, signal, and zener. The rectifier diodes are used mainly in power supplies and as protection. The most common are the 1N400X series, where X is from 1 to about 7, and their are other types designed to be fast for use in switching power supplies. Signal diodes are faster acting (usually) and designed for low power signals like logic gates and line level audio. The diodes in your distortion pedal are small signal, for example. Zener diodes are specially designed power diodes used to regulate voltage or limit a signal at a higher level than one diode drop (~0.6V). You probably won't have a big pile of these on hand until you get really serious. Consider picking up a dozen 1N400X series diodes with your order (x=4 should be ok), and a dozen spare signal diodes.

Transistors
There are about eleventeen million different types out there. They can be divided into groups by polarity (NPN vs PNP), architecture (Field Effect [FET] vs Bipolar Junction [BJT]), power rating, case style (TO92, TO220, and TO3 are most common, see chip carrier), and a dozen other ratings. For just starting I'd grab an extra half dozen 2N3904 and 2N3906 and order more as you build different things, always picking up a half dozen or so spares. They're not the best for audio work, but they'll get the job done most of the time. They are complimentary, meaning that the first is NPN and the second is it's PNP equivalent. They tend to cost about a dime each until you get into the bigger, higher current power transistors like the TIP series or larger. Transistors, especially FETs, are sensitive to Electrostatic Discharge (ESD). This means that if you build up a small static charge (smaller than makes a spark) and touch the leads it can degrade or ruin the part. That's a research topic for you, and another rant altogether for me.

ICs
There are about twentyteen billion different types out there. I'm not even going to try to state the different types, but you'll be primarily concerned with opamps. Opamps are like tiny complete amplifiers self contained in a chip package. There's a lot to learn about their use, and I can swamp you with things to read if you like. Here's some part numbers for audio opamps to run through the datasheet catalog: TL07x (x=1, 2, or 4), 4558, NE5534, LM386, LM3886 (technically an opamp, but often though of as a monolithic power amp). There's a bunch of other chips that are useful that aren't opamps, like voltage regulators (75xx [fixed regulator, last two digits = voltage], LM317 and 337 [pos and neg adjustable]), timers (NE555), gates (Don't ask, it's ugly), comparators (LM339), the list goes on. My advice would be to wait until you get to a project that uses them, buy three or so extra, and experiment.
Important! Be careful to buy exactly what you need. Chips are usually sold in multiple carriers (see chip carriers above) and it can be disappointing to order a part and have it arrive as the surface mount version when you need through hole.

Whew, and that's just a start. I really can't recommend salvage highly enough, it really cuts down the cost. Get a nice soldering/desoldering kit put together and other people's junk is your treasure!

Again, thank you so much you have been so much help

No worries. Getting started is the hard part, if you can muscle through the hard part it pays off immensely. Just keep at it!

Wow, I really rattled on this time. Hope that helps.

[GuitarLord66]

Wow, you've helped me so much, thanks so so so much for all your help salvaging sounds good, cheaper haha and the help with all the components, wow, just wow, I didn't realize there were so many different types of everything, anyway time to look for junk to salvage haha thanks again

[J M Fahey]

You should have a basic stash of:
20 General purpose NPN transistors, TO92 case
20 idem but PNP
10 General Purpose dual Op Amps (TL072)
20 GP small diodes (1n4007)
12 3A Diodes (1N5404)
Assorted Leds, Jacks, Plugs, Switches, Vero or Perfboard, a couple 9V batteries, some cheap multi-voltage wall-wart , a digital multimeter, soldering iron, wire, some tools, battery clips, some crocodiles, etc.
And an assortment of components:
Ceramic capacitors: 100/220/470/1000/2200/4700 pF ; 10/22/47/100nF
Electrolytics: 1/10/100/1000 uF x 25V
Resistors 1/4W: I follow the 1/2/5 rule: 10/22/47/100/220/470 ohms .... and so on until 1M , also a few 1 ohm ones. Any odd intermediate value as 33K or 680 ohms can be aproximated with two from "1/2/5" in series.
Build your stash at your own pace, depending on available funds, of course.
This will be *much* cheaper (and faster) than waiting for the mail to arrive.
Make a list and when buying something from a supplier, which often has a minimum order, fill it up with something of the above. Soon you'll be quite independent.
It's like going to a not too close Supermarket: maybe you only need a can of Coke, but make the trip worth the trouble and bring another things you know you will need soon.
Good luck :tu:

[GuitarLord66]

Thanks a bunch Also, are solder less breadboards a good idea? to start trying circuits out?

[Jack1962]

Sure they are , they work real well for prototyping circuits and tinkering as well, dive in and enjoy 

                                          Rock On