tone stacks and such

[LightSoundGeometry]

hello, so basically i can just chain a tone stack stage onto any type of booster for example? I see a ground path but no power ? do the tone stacks not need power? I ran a small simulation on the BB with a very simple one and it did nothing but then again the loop/path only had a ground/input/output leads and no power.


Thought I would ask here before I go off reading and googling.


I have moved up from the RM to a FF and a two transistor circuits, and also looking at adding tone controls to my amplified signal circuits. ..we are learning series and parallel in lab now using Kirchhoff law to find voltage drops and stuff ..starting to learn a lot in school , so glad i decided to take some classes, they are helping me a lot.

[midwayfair]

Is your source impedance appropriate for the tone stack you want to use? Is the input impedance of what follows appropriate for the tone stack you want to use? Does the tone stack's loss (passive) or gain (for active) play nice with the circuit you want to do this with?

This isn't a question that can be answered with generalities. You can add a tone stack to anything, whether it will work right is another story. Breadboard.

[anotherjim]

In a perfect world, the tone stack (and yes it is passive, no separate power needed), will be fed from a buffer with zero output impedance and in turn feed a buffer with infinite input impedance. This is so the tone stack values will give their intended effect. In practice the source has some impedance and the following circuit is not infinitely high impedance. Consequently the tone stack values are tweaked to match what's really there. Most folk use their ears to decide, but you need starting values. The Duncan Tonestack calculator is a good software tool for just what it says it is!
http://www.duncanamps.com/tsc/download.html

Going by what you've already built, a RM with input cap made as large as the output cap (try 100nF) - so it's an all-boost -  will give you something to feed whatever tone stack takes your fancy (although with a higher output impedance than ideal). The RM output caps assumes a guitar amps high impedance, so it's too small- make it a 1uF electro with neg toward the tone stack.
The high input impedance (1M) of a guitar amp should not affect the tone controls performance. That should get you playing without having to learn extra new stuff
In the Tonestack calculator, try using 10k as source impedance and 1M as load impedance.
Look at how different values for these change the EQ curve.

[LightSoundGeometry]

I got ya, I need to build it around a circuit and look at some stuff. maybe I should hold of on two transistors until I can add more things to a one transistor circuit. I can do switchable input caps and switchable transistors but was wanting to add something like a variable ranging pot to adjust the tone and use the switch to toggle a few transistors.

will have to to some work on the BB ! thanks!

[PRR]

> we are learning series and parallel in lab now using Kirchhoff law to find voltage drops

So you don't even know what Frequency is??

Keep your nose to the grindstone. These series/parallel lessons WILL be essential stepping-stones to frequency (tone) bending networks, but you gotta digest it GOOD.

> do the tone stacks not need power?

All the popular Active (needs power) amplifier devices, tubes, BJTs, FETs, have _flat_ response from DC to some very high frequency, and then they fall-off. For most cases we can assume they are flat across the audio band.

So how do we make bass mids and treble come out different proportions than they went in?

A Reactance is like a resistor except it varies with frequency. A cap is open for DC and short for infinite frequency. An inductor works opposite.

So put a resistor (frequency flat) and capacitor (frequency slant) in a series voltage divider. Put various frequencies in. What do you get at the division point? Depends if you tap across the R or the C. One way is a high pass. Other way is a low pass.

Suppose you don't wanna cut all highs to the max? Then you add a stopper resistor so highs fall to a point and then shelve-off. Now you are really into series/parallel/series turf.

Which is why you must *focus* on series/parallel work, digested well. For any musical need, you want to be able to burp-up a possible configuration *and* be able to analyze it on two thumbs (for mental speed; and because most audio tone shaping need only be about thumb-width accuracy).

The frequency where the response is bent depends on the circuit values (INcluding source and load). This may suggest variable values to give the user something to diddle with. (And lessening the need for pre-build accuracy.) 

And while ALL response shapes CAN be contrived with only passive parts, in real life we usually have amplifiers around. Aside from making-up any added loss in passive tone-shaping networks, sometimes working an amplifier into the network simplifies it, or the interfacing, or the user interaction. James tone control is passive but has high loss so there's always added amplification. Bax tone control includes some of that but also allows use of linear pots which track better than James' audio taper pots. Sometimes a tone shape begs for a coil which is improbably large or impossible at audio frequency; an amp can twist a cap so it works like a coil.

[LightSoundGeometry]

> we are learning series and parallel in lab now using Kirchhoff law to find voltage drops

So you don't even know what Frequency is??

Keep your nose to the grindstone. These series/parallel lessons WILL be essential stepping-stones to frequency (tone) bending networks, but you gotta digest it GOOD.

> do the tone stacks not need power?

All the popular Active (needs power) amplifier devices, tubes, BJTs, FETs, have _flat_ response from DC to some very high frequency, and then they fall-off. For most cases we can assume they are flat across the audio band.

So how do we make bass mids and treble come out different proportions than they went in?

A Reactance is like a resistor except it varies with frequency. A cap is open for DC and short for infinite frequency. An inductor works opposite.

So put a resistor (frequency flat) and capacitor (frequency slant) in a series voltage divider. Put various frequencies in. What do you get at the division point? Depends if you tap across the R or the C. One way is a high pass. Other way is a low pass.

Suppose you don't wanna cut all highs to the max? Then you add a stopper resistor so highs fall to a point and then shelve-off. Now you are really into series/parallel/series turf.

Which is why you must *focus* on series/parallel work, digested well. For any musical need, you want to be able to burp-up a possible configuration *and* be able to analyze it on two thumbs (for mental speed; and because most audio tone shaping need only be about thumb-width accuracy).

The frequency where the response is bent depends on the circuit values (INcluding source and load). This may suggest variable values to give the user something to diddle with. (And lessening the need for pre-build accuracy.) 

And while ALL response shapes CAN be contrived with only passive parts, in real life we usually have amplifiers around. Aside from making-up any added loss in passive tone-shaping networks, sometimes working an amplifier into the network simplifies it, or the interfacing, or the user interaction. James tone control is passive but has high loss so there's always added amplification. Bax tone control includes some of that but also allows use of linear pots which track better than James' audio taper pots. Sometimes a tone shape begs for a coil which is improbably large or impossible at audio frequency; an amp can twist a cap so it works like a coil.

frequency is still a few chapters away ..parallel is coming next week

I am taking a step back from 2-3 trannies and still working on the RM for a while it looks, but thats okay, a lot to learn.

i am still in Series circuits ..and making videos of me running the simulations from lab lol

I will get there one day !