Fundamentals

[PsycoDad]

I am not to guitars but I am new to stomp boxes and modding stomp boxes. I want to understand how the capacitors and resistors ICs and diodes affect the tone and amount of effect. Can anyone educate me on the basics of the Boss sd-1 tone circuit? What caps affect the tone and what exactly affects the gain?

[Kipper4]

Hi and welcome to the forum PsycoDad.
Maybe you should check out R G Keens Technology of the tube screamer.
Happy learning.

[PsycoDad]

Thank you very much for the advice.

[GibsonGM]

Welcome, Psycho....AMZ labs (link at top of this page) would also be useful once you've digested a little of R.G.'s awesome site. 

The net is full of basic electronics tutorial type stuff, and Youtube as well.  One thing to keep in mind as you try to learn a little - it's all related.  Someone talking about capacitors at high frequencies for ham radio IS connected to us using capacitors for lower frequencies as tone controls as the like.     Seems that there are 3, 4 properties of each of the main parts like diodes, caps, resistors - that you need to "get", and then it starts to make sense.
   
Such as :  capacitors pass higher frequencies more readily than lower ones.  At DC, they are an open circuit but will still allow AC to come thru. 
Diodes turn on at a certain voltage that is inherent in how they're made (about .5, .7V for silicon diodes, for example, varies by type).  Won't conduct til then.
Understand what a sine wave (an AC signal such as that from your guitar) is, and how it's different than DC.
Learn about and begin to use OHM'S LAW, it is the KEY to all other understanding (IMHO).   Even rudimentary use of it ("how many volts are dropped across these 2 resistors?") is giant in terms of understanding.

To start with, IC's (OPAMPS) are mostly used by us as small amplifiers to bring a .5 volt AC guitar signal up to a useable level of a couple of volts, so we can use the properties of the diodes and caps etc. that come after it, and to condition the signal.   There are many other uses, but start with that, as a "black box". 

[PsycoDad]

Thank you for that piece of info. I am really wanting to understand how all this works, so  I can build my own pedals. I feel like  there is something that commercial pedals are missing.

[slashandburn]

If trying to absorb tomes of text full of intimidating looking equations isnt helping much I found that breaking down old scrap electronics and trying to find some way of storing the components in a somewhat organised fashion helped knock down a few big obstacles and joined a few dots for me.  Its monotonous and time consuming, but after sorting through several tubs or random value resistors, caps and diodes, the naming and numbering conventions made a lot more sense.  Its definitely not for everyone, and Im not suggesting ripping open your TV to look at the circuitry to try and see how it works.

That said, in my experience (so far, Im still a novice myself!) theres really no alternative asking lots of questions and sitting up late trying to digest articles that make very little sense.  Eventually something will click and a huge curtain will lift.  

Good luck and have fun.

*edit*  Sorry, not quite answering your question. Its not the DS-1, but this article helped me incredibly. Each section of the circuit broken down and explained.

http://electrosmash.com/tube-screamer-analysis

[PsycoDad]

I appreciate any and every reply. Every single one helps. Right now, I am looking at the Boss SD-1 and it's corresponding schematic trying to get it all to make sense.

[PBE6]

For what it's worth, I've found the layered approach seems to work well when trying to understand stomp boxes. Circuits are made of individual components, organized into functional units, coupled together and then tweaked to make it all work. Underlying it all are bigger concepts like impedance and signal filtering, and underlying that are other fundamental concepts from physics. Sometimes you can get away with understanding only one layer (a simple Fender-style volume or tone knob) and sometimes you can't (virtually any production line stompbox, even the uncomplicated Fuzz Face!).

As you build and debug your pedals, you'll begin to identify concepts in different layers (two resistors makes a voltage divider, voltage dividers are used to control gain in non-inverting opamp stages, etc..). You may not understand everything at once, but eventually you'll start to see patterns that make everything fall into place. It's also worth reading and (re-reading!) any article at GeoFEX that catches your eye. You never know what you'll find buried in an old article that you thought you understood completely!

[slashandburn]

I just realised I was confusing the sd1 with the ds1, sorry. the good news is having just checked, the sd1 has a lot more in common with the tube screamer than the ds1. So those tube screamer analysis articles should definitely help some.

[ashcat_lt]

...two resistors makes a voltage divider, voltage dividers are used to control gain in non-inverting opamp stages, etc...

The one statement that opened my eyes to how any and all of this works the most was when PRR said "Everything useful is a voltage divider".  Sometimes it's frequency dependent, sometimes it's "hidden" in an IC, sometimes you have to squint to see it, but once you learn to find the voltage dividers the whole thing falls together a lot quicker and easier.