how to figger out the tone stack?

[plexi12000]

i know most of you guys are very advanced ....and it's prolly a pain in the ass to deal.... but i hear lots of talk about the tone stack being the place to play with values, etc.

how do i figure out the "TS" of a pedal?

[Transmogrifox]

It's hard to know where to start explaining. Are you asking how do you identify the tonestack in a pedal, or are you asking how you know what to do with components in the tonestack?

This is a loaded question because there are several basic tonestack designs each with their own little nuances and what a component change means.

The most common in a stompbox is the BMP (Big Muff Pi) one-knob job which blends between a high-pass and low-pass filter.  This one has a mid scoop dependeng on how far the high and low corner frequencies are situated, and can also have a mid-hump if overlapping.

The next in line is the Fender-style 3-knob control with an interactive relationship between all components in the tonestack.  For example, you can't change the treble cap without having some effect on the mids and bass.

Then there is the Tubscreamer tonestack and also many of these metal pedal tonestacks with an active filter forming something of a 3-band EQ and even a parametric EQ in the case of the Boss Metal Zone for example.

The fastest practical way I can suggest is to learn how to do circuit simulation and use a free tool such as LTSpice to obtain frequency response graphs for a tonestack.  From there, make component changes and see what happens. 

Once you have watched how a certain component changes the tonestack behavior, then you will have a good practical understanding of what "big cap here, little cap there" might do to the sound of the tonestack.

If you have a specific tonestack in mind I am happy to step you through it and identify what parts make it sound the way it sounds.

[plexi12000]

just more like how to "locate" it in a circuit?  i know....i guess its hard to tell someone. especially a newb

[plexi12000]

Transmogrifox---  actually, it's funny....you mentioned the very two pedals i'm most obsessed with at the moment- lol

built a 808 and love it.  wanna do one of the BMP's next.

[J0K3RX]

Start here http://www.muzique.com/lab/main.htm  and read all of the wonderful free documentation that somebody was kind enough to share with all of us...

[GibsonGM]

^ +1

Also, read up on "R-C filters".  Just enough to understand what and *kind of*  'how' a Low pass and High pass filter work....LPF  HPF.

Those babies are EVERYWHERE, and are subject to your whims when building!  Luckily the formula stays the same for high- or low pass

Get you started with understanding what you'll see on Jack's AMZ site, which is an awesome resource!
http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

GENERAL definition but subject to a lot of variations:  "Tone stacks" and "tone controls" are just made up of R-C sections that are tuned to control a specific 'area' of the audio signal, and are chained together if there is more than one.  Yes there are tricks to designing them, and yes, there are a few rules, but over time and with the help of these resources, you come to understand how it works.  1-knob tone controls are great ways to get in the game, like the BMP mentioned above!   

[midwayfair]

Also, download Duncan's Tone Stack Calculator! Try to learn what each tone stack in it is doing, and you will get a huge number of ideas and variations, plus you'll get a better understanding of variable filter controls in general.

The best way to start identifying building blocks of any sort is to look at a schematic for a circuit that has what you're talking about -- a tone control, or a tone "stack" (multiple tone controls) -- and see what that control is varying. Then look in other pedals and/or other places in the same schematic and see if you can identify something that looks a lot like it, even if you have to squint or turn your head sideways. If you aren't sure what a particular control is doing, ask a specific question about that pedal.

[highwater]

Just about any capacitor in a pedal will have some effect on the frequency response. With a 9v supply, it's awfully difficult to break anything by randomly replacing caps with different values. It is often easier to just see what happens and figure-out the why once you've found the value you like. If the circuit has a tone control, start by replacing whichever cap is closest to the tone pot (closest on the schematic, that is) with a slightly smaller/larger value, and see what happens, then work outward from there. If the circuit doesn't have a tone control, then start with the DC-blocking caps at the input and output; although their capacitance is usually selected simply to pass all guitar frequencies, you can almost always cut bass by making one of both of them smaller -- the Rangemaster is a classic example of how dramatically this can affect the sound of a pedal.

A breadboard is, as usual, an ideal tool to experiment with this. Build your circuit on one, and you can just go through and (one at a time - keep notes) replace different caps with the next-bigger or next-smaller value, and listen to what happens -- this can (will?) be more useful than understanding the math behind it.

[Ice-9]

Over at Geofex a complete breakdown into sections explaining how each part of the TS808 works including the tone section is available. link below. Thanks to R.G. Keen for the excellent info at Geofex

http://www.geofex.com/article_folders/tstech/tsxtech.htm