distortion project/adding an active tonestack

[rocket88]

i posted this over at DIYSB and FSB, but i know some of you guys may not be members over there, so i thought i would post it over here and get some other points of view and suggestions, plus thought some of you may be interested in my current idea, and where i'm going.

i've decided to embark on another build of my own design, but i'm starting with following something similar to the quantum mystic. the issue is that i'm having a little trouble wrapping my head around something i know i know, but i'm missing something stupid. having some sort of brain fart. the basic idea is adding a tonestack to a circuit, and where to place the volume control.

using passive tonestacks, with the LPB as a gain recovery stage, and trimmer to control the final output, is super easy, but i'm looking at adding an active bax in a box and for some reason it has me thrown for a loop.

so if i take the ross distortion



and want to add the bax in a box tonestack



in my head, i'm thinking that if i remove the output from the ross distortion i should replace it with a fixed resistor, say 50k to have max output from the ross, to control the output into the first gain stage of the tonestack opamp, set the trimmer to prevent clipping, and to have a master output i would have a simple voltage divider at the end of the tonestack. but i'm not 100% sure that is the best idea. i really like the idea of having an active tonestack, and have plans to use this for a few different projects, one being using it in the tiny giant amp and ruby tubey, but i have to get a a little better understanding of how to properly add it to another effect first, rather then in a separate enclosure.

i've worked on a schematic for what i'm thinking, no values in place atm.

[Chris60601]

Sweet. Very interested in this as I'm looking to much of the same.

Thanks rockett for taking the initiative!!

[rocket88]

hey. i'm full of ideas. not all of them good or great, but full of them.  we'll see how this turns out, i've got the layout figured out, posted under the contributions page, now it's just about making sure the science and math is correct. always good to have another pair of eyes take a look and verify ideas.

i really like the bax tonestack, since it allows you to control bass, mids, and treble, with only two knobbies, and minimal parts. i'm just thinking that as i'm working on creating my business this may be a better direction to move as far as tone control rather then the typical passive controls. so you could take it and make something like a BMP, remove the tonestack and gain recovery stage, and pop this sucker in its place or TS, or whatever you like. i've figured out what i think will be some better values for the tonestack, remember bassist here. as with any design i've done, i like to spend more time planning it all out, then the rest falls into place when breadboarding. shit, i've got the box designed already .

[alex.s]

You might be able to do without the 50k altogether, since this kind of circuits aren't all that loud due to the clipping (which actually makes the active tone option a very fitting solution!).

Also, I'm thinking perhaps you could lose C5 as well. It's presumably there to cut some high frequency and mellow the distorted signal some, I guess you won't know whether or not you need it until you try...!

Sorry I'm not being of much help here, just chipping in a couple of thoughts really...!

[rocket88]

exactly alex. the way i figure it the new output should be something like 100k like most other effects, which should help give enough output, but again wont really know till i get breadboarding with this.

you know me, any contribution is a good contribution, so it's all good and glad to have you chime in, shit isn't that why we're hear? to help each other?

the interesting thing is you could be right about C5, but since this first experiment is really based off the idea of the quantum mystic, C5 is still there.

btw, to help give a better idea of this idea of the concept i'm going for here's the quantum mystic schematic as determined with the help of vince.



probably i should have posted it at the beginning.