confused on Wiring Potentiometers

Started by Fndr8875, January 29, 2016, 01:37:12 AM

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Fast Pistoleros

Quote from: Dito on January 31, 2016, 06:30:17 PM
A "C" pot is reverse logarithmic. It's the same curve as an "A", but inverted. It's #4 in this diagram from Secret Life Of Pots.



I can tell you what they are, but I'm unable to explain much further. I'm not an engineer or a mathematician.

thanks ! I can see it ..I do not own a FG or an Oscope ..I am in my second semester and we are looking at diode characteristic curves , and this is pretty much the same thing with voltage on the Y and rotation on the X axis

I guess I could of googled the picture lol

Dito

It's all good. I want an oscilloscope even though I have no idea what they're really for or how to use one. They're just cool-looking gadgets.
"All that's left of me is slight insanity / What's on the right, I don't know." - Sugar (Bob Mould), Hoover Dam

Fast Pistoleros

I am new to the oscope as well but I think in its basic function is voltage on the Y axis by Time in second on the X axis . it is looking at a 360 degree or 180 degree line or wave in DC or AC form if I am not mistaken.

I think you can set the X and Y axis to other values like in the picture above , or do you need special software?


Fndr8875

Im waiting on some perfboard to redo build instead of using the weird radioshack IC type board i was using. I still stand by my post that using the resistor from output to ground is a way of semi turning a linear pot into a log(audio) pot. I have used it in my guitar and yes maybe you loose a little bit of resistance but the taper is more smooth than that of a linear where u get all ur taper in the last tiny bit of turn of pot.

http://www.seymourduncan.com/forum/showthread.php?188213-Convert-Linear-pot-to-Audio-Log

Fndr8875

Im just having a little chuckle.... how is it impossible to take a breadboard layout and transfer it to perfboard? I understand schematics in the way that your connecting components from one to the next in a certain order...yet almost every schematic shows nothing concerning the 3pdt switch, and potentiometer wiring in relation to the 3pdt. I have used multimeter to confirm continuity so my ground is good, My led lights up when switched, power measures to 9volts, im confused that so many people are confused or dont have an answer as to specifically where my two pots would wire say on perfboard as well as my 3pdt. I just have 2 3pdt wires...circuit in and ciruit out. I also have input and output on volume pot. I see from breadboard layout the fuzz pot wires between the 330ohm resistor and 2.2uf cap, but this is my first build and ill just yeild to the fact no one could suggest where one pot could be wired to my circuit on probobly the most common built circuit of all time lol sorry for the sarcasim just figured someone would have a suggestion. Ill start by wiring circuit in to input cap and circuit out to output cap, ill run ground from pot to pot to output jack, and idk i guess input on volume pot in series with circuit input.

Fndr8875

Oh and thanks to Dead Astronaught for the layout   :) :) :)

it has made schematics click a little better. Your site is awesome, if i had the dough id happily buy something from you. Your etching on enclosures is sweet.

GGBB

Quote from: Fndr8875 on February 02, 2016, 03:43:39 AMI still stand by my post that using the resistor from output to ground is a way of semi turning a linear pot into a log(audio) pot.

No one is questioning that - it's well known.

Quote from: Fndr8875 on February 02, 2016, 03:57:59 AMim confused that so many people are confused or dont have an answer as to specifically where my two pots would wire say on perfboard as well as my 3pdt.

I gave you an answer earlier for the volume pot - what part of it didn't you understand?

As for the fuzz pot - it doesn't connect to the 3PDT at all - it connects the same way on the breadboard diagram as on your perfboard - pin 3 to Q2 emitter, pin 2 to 22uF cap, pin 1 to ground.

Only you know which wires are which on your perfboard.
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induction

Quote from: Fndr8875 on February 02, 2016, 03:57:59 AM
Im just having a little chuckle.... how is it impossible to take a breadboard layout and transfer it to perfboard?

Who said it was impossible? I said it was inadvisable, and suggested using a schematic instead. Enjoy your chuckle.

Quote
I understand schematics in the way that your connecting components from one to the next in a certain order...
...
Ill start by wiring circuit in to input cap and circuit out to output cap, ill run ground from pot to pot to output jack, and idk i guess input on volume pot in series with circuit input.

If you look at the schematic, you'll see that this is not how the circuit goes together. The output cap connects to lug 3 of the volume pot. Lug 2 of the volume pot is the circuit output, which connects to your bypass switch. See how useful schematics are?

Quote
ill just yeild to the fact no one could suggest where one pot could be wired to my circuit on probobly the most common built circuit of all time

You didn't ask where the pot is wired in the circuit, you asked where it was wired in your layout, which you haven't shared with us.

Quote
lol sorry for the sarcasim just figured someone would have a suggestion.

You've gotten two pages of responses. The problem isn't lack of suggestions. The problem is our difficulty in figuring out specifically what you don't understand. I think this is mostly because this is your first build, and you haven't learned the conventions and vocabulary yet. It's great that you made your own layout (I assume), but since you based it on another layout and not a schematic, I'm not at all surprised that you got lost.

Maybe this will help. It's useful to think of a pedal as two mostly independent circuits. The first is the effect circuit (which includes the pots). This is what you built on the breadboard. The second is the 'wrapper': the offboard wiring, the bypass switching, the led, etc. For the most part, the same wrapper can be used on almost any pedal. Once you figure it out once, you can use it over and over. The wrapper isn't usually included in the effect schematic by convention because the builder is free to choose or invent whatever wrapper they like without changing the operation of the effect circuit. Lots of people use the same wrapper for many or all of their builds.

Fitting an effect circuit into a wrapper is much easier with a schematic. Schematics are designed to communicate the operation of the circuit. They are easily divided into building blocks that you start to recognize after you see them over and over. Layouts tell you how to put the circuit together, but give no clue about how the circuit works and are not easily divided into recognizable building blocks. All chuckles aside, you will continue to get lost until you start referring to schematics when you build, especially when you design your own layouts.

On a more personal note, aiming sarcasm at people who are trying to help you is a good way to get them to quit. Consider finding another way to deal with your frustration.

duck_arse

a correction: I found this diagram, which says W goes slow - fast - fast - slow, not what I said. from "Keiko corporation".

discuss.

don't make me draw another line.

PRR

> I do not own a FG or an Oscope

You are over-thinking.

(We never turn a pot so fast we need a 'scope to see what it does.)

Put 1.5V end to end on a pot.

Turn wiper one way. 0V end to wiper.

Turn wiper to the center. 0.75V end to wiper.

Turn wiper other way. 1.5V end to wiper.

This is a Linear pot. If you plot it on graph paper (can you even buy GP today?), or a tic-tac-toe board, you get a straight line.

If the center position gave 0.1V to 0.2V, it is not Linear. "Audio taper" is typically 10% or 20% (not 50%) at the center.

If you need the "full" action of the pot you will turn the knob to 0, 1, 2,....9, 10, measure at each point. Then go back for 0.1, 0.2, 0.3, ......... 9.8, 9.9, 10.0. But if you waste a week doing this, you find that "linear" pots are near linear except at the ends, "Audio" pots are a lot like two linear segments butted together. There's little reason to be potting 100 points on a finger-knob pot.

This assumes the end with 0V is "minimum". If the pot is non-linear, say 10%, the center will be 10% from one end and 90% from the other end. OR 90% from one end and 10% from the other end, "Reverse Audio". This becomes a 3-D problem as you look at the terminals from the back, the knob from the front, and try to figure out which way is which. Comparison to known-taper pots is good check-up.

Yes, you CAN set up a motor and a plotter, could be a 'scope, could be a math-package, make lines on screen or in a graph. Pot-factories probably do.

There used to be GOOD pots, with true logarithmic or sin/cos taper accurate to a fraction of a percent. These were used in analog computers. Say your airplane has 432 horsepower, 900 pound load, 7 degree angle of attack, how does it fly? but say you have not built this airplane yet. A properly set-up analog computer with pots for every variable can compute such answers pretty quick.
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thermionix

Quote from: duck_arse on February 21, 2016, 10:25:44 AM
discuss.

It's reverse audio (anti-log) taper for the first half of clockwise rotation, audio taper for the second half.

Jdansti

#32
Quote from: Fndr8875 on February 02, 2016, 03:57:59 AM
Im just having a little chuckle.... how is it impossible to take a breadboard layout and transfer it to perfboard? I understand schematics in the way that your connecting components from one to the next in a certain order...yet almost every schematic shows nothing concerning the 3pdt switch, and potentiometer wiring in relation to the 3pdt. I have used multimeter to confirm continuity so my ground is good, My led lights up when switched, power measures to 9volts, im confused that so many people are confused or dont have an answer as to specifically where my two pots would wire say on perfboard as well as my 3pdt. I just have 2 3pdt wires...circuit in and ciruit out. I also have input and output on volume pot. I see from breadboard layout the fuzz pot wires between the 330ohm resistor and 2.2uf cap, but this is my first build and ill just yeild to the fact no one could suggest where one pot could be wired to my circuit on probobly the most common built circuit of all time lol sorry for the sarcasim just figured someone would have a suggestion. Ill start by wiring circuit in to input cap and circuit out to output cap, ill run ground from pot to pot to output jack, and idk i guess input on volume pot in series with circuit input.

Hey folks, his main question is how to wire his off board components. I see he's confused because he's talking about wiring his pots to the stomp switch. Re-read his comments above. I don't have time to answer his question now, but I'll come back to this thread later, fendr, and try.

Edit:

What the hell. I didn't need to sleep. :)

See if this answers your questions:

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R.G. Keene: EXPECT there to be errors, and defeat them...

Fndr8875

Thank you J. thats all i  was trying to get at. I think new people are overwhelmed with replys to there questions with terminology and statements like well just learn schematics and get a total understanding of electronics and youll fig it out. Its hard to ask a question when ur new and you dont quite understand how to even ask the question. Im grateful for ppls help but i do fell there are just as many post condesending to new people as there are new ppl doing no research and expectiing others to write it all up for them. I realize i need to carefully word my post if i am asking a question, now that i have a small amount of understanding. Thanks to everyone who posted and i mean no disrespect to anyone, think its misunderstanding of what the question is and frustration from people on both sides, anyway

induction

Quote from: Fndr8875 on March 09, 2016, 07:05:37 AM
I think new people are overwhelmed with replys to there questions with terminology and statements like well just learn schematics and get a total understanding of electronics and youll fig it out.

Let's be fair here. You stated that you wanted to "have the ability to take anykind of layout and build the pedal on whatever kind of board i have." The only reliable way to do that is to learn how to read schematics. That's not condescending, that's just reality. If what you want to do is beyond your current ability, it's not condescending to suggest an area to focus your efforts.

I suggested learning schematics because it will make this hobby much easier and more enjoyable. It will make it possible for you to do what you said you wanted, and it's not nearly as difficult as you seem to think. Knowing how to read schematics is a far cry from having a total understanding of electronics. It's more like learning the alphabet.

I'm glad you got an answer to your question.

Jdansti

Quote from: Fndr8875 on March 09, 2016, 07:05:37 AM
Thank you J. thats all i  was trying to get at. I think new people are overwhelmed with replys to there questions with terminology and statements like well just learn schematics and get a total understanding of electronics and youll fig it out. Its hard to ask a question when ur new and you dont quite understand how to even ask the question. Im grateful for ppls help but i do fell there are just as many post condesending to new people as there are new ppl doing no research and expectiing others to write it all up for them. I realize i need to carefully word my post if i am asking a question, now that i have a small amount of understanding. Thanks to everyone who posted and i mean no disrespect to anyone, think its misunderstanding of what the question is and frustration from people on both sides, anyway

You're welcome. Glad you got your question answered. I think that overall, the responses in this thread were well meaning and intended to be helpful.  We all have to remember that part of the learning process is learning how to ask the right question and how to redirect others back to the main question. It's easy and tempting for the original poster (OP) to get sidetracked by well meaning but off topic responses. 

In addition, we are fortunate to have a truly global presence on this forum, which is unique. There is a large range of proficiency of the English language, even for those who live in English speaking countries, and this sometimes complicates our communications. Add to that the range of age of our forumites and it can become a little like the Tower of Babel. 😊

Just a last bit of information regarding your original question. While pot connections are always shown on schematics and layouts, the input/output jack connections are sometimes partially shown on these images by only showing where the signal "enters" and "leaves" the circuit. It is very rare for schematics and most layouts to show the jacks, board, and LED connections to a 3PDT switch and the off board ground connections.  It's just assumed that you know how to connect these things.  We normally rely on separate layouts for the wiring of these off board components. 
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R.G. Keene: EXPECT there to be errors, and defeat them...