Tone Control

[Alpha579]

Hey all,
I was thinking about adding a tone control to my really simple fuzz, and i know what i want, just not sure how to make it  :oops: .
I want a simple tone control that is flat @12oclock, and turning down cuts treble, and turning up cuts bass. And i dont want many DB's lost in the circuit.
Thanx 4 input,

[ExpAnonColin]

Well, if you really want to have no DBs lost.. you'd have to create filters that actually boost as opposed to cut.  I'd advise putting one side of the output directly to the out and one side of the output into a unity gain op amp (as a buffer) and then into the center lug of a pot.  Either lug of the pot would then go to a bandpass filter of some sort...  then both to the output.

It'd probably be a lot easier to make the circuit purposefully high end, in any way you'd like, and then have a simple lowpass filter at the end, so that when it was turned one way, you'd get all of the high end, in the middle a bit of cut, and on the bottom it'd be a lowpass filter.

Hope I helped.

-Colin

[Alpha579]

ok, ill try and make it simpler...
CAn u make a low pass filter (no inductors) that throws to ground(eg i once read u could put a res & cap in series to ground 4 low pass?).

[Nasse]

I think the answer for your first q is Baxandall tone control, look for it, I suppose there are plenty of schemos around :wink:

[ExpAnonColin]

ok, ill try and make it simpler...
CAn u make a low pass filter (no inductors) that throws to ground(eg i once read u could put a res & cap in series to ground 4 low pass?).

Sure, just wanted to accomadate to your "No Db loss" in your original post.  Try the lowpass in the FAQ:

Add a lowpass filter

A lot of distortions don't have tone controls. Here is an easy lowpass filter you can add. It will reduce your output a little but if your distortion pedal has lots of gain, this shouldn't be a big problem. If you think about it, this can go right on the lugs of the output volume pot. Use a small trimmer mounted on the lugs of the output pot along with the capacitor.

-Colin

[Alpha579]

Sorry, i ment low cut  :oops:

[spongebob]

A simple RC hi-pass (low cut) filter looks like this:

Code Select Expand

In      | |  C                     Out
o-------| |----------+-------------o
       | |          |
                   ---
                  |   | R
                  |   |  
                   ---
                    |
                    |
                  -----
                   ---
                    -

At frequency f = 1 / (2 * Pi * R * C) you will have a 3dB attenuation of the signal, lower frequencies will be attenuated more, higher less.

If you look around, you will find more complex filter designs with a better (steeper) frequency rolloff, but that depends on what you are trying to achieve. Maybe have a look at Duncan's Tone Stack Calculator, it's really good for simulating tone controls. And it's free! :wink:

[ExpAnonColin]

Add a low cut filter

Here's an interesting one to try, put a low cut if your distortion  has too much bass.

Also from Aron's mod sections.

-Colin[/img]