the role of components

[Blatant]

Hi i'm a huge electronics newbie - i've built a few clone stomp boxes but that's like copleting a jigsaw puzzle, I don't really know much except x part goes here...

My question is - I searched the FAQ but couldnt find:

what do the parts in a pedal do to sound individually?
IE: a capacitor, resistor, diode, transistor does what to sound?
I know how they effect current, etc but how does that alter what we hear?

[GibsonGM]

There is a pretty good breakdown on R.G.'s site, the GEOFEX link up top, called something like "What part does what?". If you go there and search "What part", I'm sure it will come up.

Those are good questions, and can screw you all up when you're new!
For starters, diodes tend to be used for clipping - adding overdrive or distortion to a pedal.  Sometimes they're for rectification (turning an AC signal into DC), and can play a role in frequency doubling, like in an Octavia pedal.  They are a 1-way valve that only lets voltage of 1 polarity pass.   They can protect a circuit from a backwards-inserted power cord, or pass only 1 polarity of signal. Zener diodes can give reference voltages, and regulate voltages.

Caps block DC (very important!) and have 'reactance' rather than resistance....they act like resistors which allow more current thru at high freq's than low, so in combination with resistances they become filters, allowing us to select a range of frequencies to boost, distort, or remove.

Resistors do lots of stuff, like give us the proper voltage and/or current level to or from a device.  Big values are noisier than small (hiss).  And as mentioned above, the work in conjunction with caps to make high pass, low pass, band pass and band stop filters, which are found ALL OVER even a simple pedal (wikipedia is great for checking those out!). 

Transistors, opamps, jfets, mosfets and the like amplify signals, and can act like switches.  Each has its own particular contribution to the sound of a circuit, depending on the network of parts around it and how it works by its own nature.  Some are 'warmer' sounding (JFETS/MOSFETS), some are more 'sterile' (opamps, transistors), but that is also subjective and can be altered a little by the - you guessed it - filtering you use before and after them.

There's a start for you, check out GEOFEX and search other web sites, it will become clear in a little time if you go looking!!
Good luck and happy building,

~Mike   

[R.G.]

what do the parts in a pedal do to sound individually?
IE: a capacitor, resistor, diode, transistor does what to sound?
I know how they effect current, etc but how does that alter what we hear?

That question can't be answered directly in that form. At least not like I think you want to hear.

You can't, for instance, say that bigger resistors add/subtract anything from sound (aside from thermal noise, hiss; and even that's dependent on the rest of the circuit). Using a bipolar transistor instead of a JFET, or a germanium instead of a silicon, or a bigger or smaller capacitor cannot be said to affect sound in one specific way.

It's the interconnection of parts that affects sound. For instance, the simplest filter is a single resistor and a single cap. Whether this combination is a high pass filter or a high *cut* filter depends on how they are connected. Getting a sound you want is not as simple as getting the "right" capacitor, resistor, transistor, and so on. It's how you connect them. It's very much like having a winning football team isn't as simple as getting the biggest, strongest lineman, the fastest receivers and the most-accurate quarterback. It's both *how* they play together and *how well* they play together, which are two different things.

Kudos on the question though. It's a common one among the beginners that come here.

aron, I think that perhaps this question, perhaps in a more standardized form, and a version of my answer need to be in the FAQ. I'd put it on geofex, but it seems like remarkably few beginners read that anymore.

[petemoore]

  For now a reader can do well by simple copy/pasting terms into google.
  "Capacitor"
  There were [I guess still are] some very good online richly texted / interactively diagrammed / graphed explanations of electronics/components etc.
  I wish I had better memory for source or site names.

[FiveseveN]

MAKE: has a series of videos with some general info about a couple of parts: http://www.youtube.com/view_play_list?p=970BF3F6D77B12E8
But in general, it all depends on how in-depth you need to or believe to need to understand electronics. As your own experience can tell you, one barely needs any insight to practically build an effect. But if you want to develop one "from scratch" and it needs to be commercially viable, sturdy, predictable and versatile, you probably need to pass the "serious hobbyist"/"EE undergrad" mark

[bipedal]

I learned A LOT from reading (and re-reading, then tinkering, then re-reading again...)  R.G.'s "Technology of the Fuzz Face" and "Technology of the Tube Screamer" articles (easy to find both online).

I have a minimal electronics background, and my first time through those articles I may have understood less than 20% of what I was reading, but each time through gave me a bit more clarity.  Understand the basic circuit components, then look at the mod suggestions and work to follow the logic of how those mods accomplish what they accomplish.

[Electron Tornado]

Here's a link to a page from Beavis Audio that will help give you an idea of what does what in a simple booster circuit:

http://www.beavisaudio.com/techpages/HIW/hiw1.gif


If you want to know how it sounds, build the circuit and change the values of individual components one at a time. You can replace a resistor with a potentiometer, for example, and hear how different resistance values might affect the sound.

Take lots of notes - you will find those notes useful later.