Overdrive, Distortion, etc - How To?

[strungout]

Oy, I'm looking for a basic run-through of creating an overdrive/distortion circuit, step-by-step of what's happening in the circuit, specifically for stomboxes.

Does anyone have a website address, tutorial, etc?

I can'T seem to find anything that doesn't take me and throw me into alot of calculation and whatnot...

Ciao.

[smoguzbenjamin]

Well, to make almost any circuit you'll have to sit down and do a little math. But here's an article that makes it easy: http://www.generalguitargadgets.com/v2/richardo/distortion/index.html

[aron]

I love this site!

http://users.chariot.net.au/~gmarts/ampovdrv.htm

[petemoore]

Small Bear's Tweek-O is a good begginner pictorial essay on SB building.
 A good one to read into as much as you can is GEO Tech articles...the one on the Fuzz Face is quite comprehensive and much of the non equation parts you can apply to any build.
 I socket input caps on first builds of a type. I socket transistors consistantly.
 Recommended is to start with something simple like an LPB-1 or other useful booster, I use boosts all the time these days...fantastic for clean or puching up a weaker Fuzz circuit etc.
 Have a great build !!!
 Also check out the beginners forum.
 Check out all kinda links, schematics 2, root around and scroll down on these sites...there's tons of info.

[Marek]

Oy, I'm looking for a basic run-through of creating an overdrive/distortion circuit, step-by-step of what's happening in the circuit, specifically for stomboxes.

Does anyone have a website address, tutorial, etc?

I can'T seem to find anything that doesn't take me and throw me into alot of calculation and whatnot...

Ciao.

Ciao!

"...step-by-step of what's happening in the circuit..."

Well, if you want it without any math involved, then:

1. audio signal enters the circuit
2. signal passes through a RC filter
3. signal gets amplified
4. signal gets even more amplified
5. signal would get even more amplified, but the diodes don't let that happen, instead they clip the peaks of the signal
6. if you try to amplify the signal even more, then your peaks get clipped  even more ( and as an effect you get a distortion of the audio signal )
7. then come few more RC's to get the frequency range of that audio signal right
8. signal exits the circuit

Otherwise, the Technology of the Tube Screamer @ www.geofex.com is a must read, as well as other websites mentioned...

Greetings,
Marek

[Jered]

http://www.diystompboxes.com/sboxforum/viewforum.php?f=6
 Jered

[bobbletrox]

I've seen a few tutorials about making distortion and overdrive with opamps, but nothing really explaining how to build transistor circuits.  :?

[strungout]

Lotsa responses

Marek: That's a good, simple start, and it does help. Any similar explanation on a transistor? I might seem quite ignorant, but I'm really looking to make sure I'm getting it.

Thing is, after building a working Big Fuzz (muff Fuzz, muzz fuff, etc. Gets confusing...), I figured I could do something similar, took the Vox Tone Bender schematic from the Article "The Technology of the Fuzz Face" (RG Keen) and used the same caps, resistors, but changed the transitors to general purpose ones i had. Resulted in a incredibly faint sound that died before it got to the output jack, as probing around let me hear. Couldn't make it work, so I dropped it and tried something less complex: Electra Distortion pedal. Same Resistors, caps, transistor (2n3904), substituted the 1N34A and 1N4001 for a 1S34 and 1N4002. While more successfull, all I get is a clear sound, that doesn't even sound amplified. So I don't get it, and I wanna get it

Before substituting the diodes, I did a cross-search on NTE, 1N34A gives out NTE110MP (Two matched diodes, one germanium, one a "point contact" diode). I searched for the one I had, 1S34, which gives out NTE109 (General Purpose germanium diode, fast switching). The search for 2N4001-2-3-4 all result with NTE116 (General purpose silicon rectifier), so, seemed like it would work...but I guess I'm missing something. The schematic I used is at the bottom of this page http://www.geocities.com/j4_student/schematics.htm.

Anyway, gonna check out all those links

Ciao.

[Jered]

Marek: That's a good, simple start, and it does help. Any similar explanation on a transistor?

 Sure is, check my previous post.  Jered

[strungout]

Ok, I tried debugging, and after looking at those links you guys gave and some debugging links, I can say that I understand much more. But I still only get a clear sound out of that Electra. R.G. Keen's debugging page says to work as an amplifier, C must be greater than B and E, B must be greater than E by .4 to .7V and C must be greater than E by at least 1V. I Changed the two resistors from 47k to 4.7k and 2.2M to 2M. As of now my voltage reading on the transistor are

C=1.78V
B=1.10V
E=1.08V

1 out of 3. I'm at a lost as to what I should tweak to get 3/3. Any hints (or outright solution  :wink: ?

BTW the 2M (2.2M in the schematic) is the base bias right?

And since I don't get any distortion, could it just be that my diodes aren't distorting?

[javacody]

It probably is the diodes, but the pickups you use are important too. Single coils work the best, especially in series (neck middle combo).

[strungout]

I use single-coils ( I have a Squier Bullet strat). I got the electra to work, experimented with more/less diodes, changed their direction, changed output cap. I got an ok sound, but its too low in volume, so trying to boost that...