how can i add a mids control to a tube screamer circuit?

[snow123]

update: the distortion is gone when r1 is at 22k and when c1 is at 10nf, but now when the mids is all the way up, its below -4db.

[snow123]

am i understanding correctly that you are only cutting mids? if so, have you considered a bridge T filter? its easy, it can scoop the mids or leave them alone with a single potentiometer. there are also some more interesting filters based on a bridge T filter.


cheers

no, i want it to cut AND boost, but rn its only cutting, which is not what i want.

[snow123]

it looks like there isnt any distortion happening at the output of the tone stage, before the mids control.

[snow123]

would putting the active mids control in between the clipping stage and the tone control decrease the distortion at all?

[snow123]

so i guess the mids have to be below -4db in order to not distort..

[snow123]

YALL I MADE IT NOT DISTORT WHILE STILL BOOSTING THE MIDS!

[snow123]

i basically just increased r2 to 22k, increased r10 to 470k, and reduced r3 to 330r. and now it doesnt distort and still boosts the mids!

edit: the main reason i changed r10 and r2s values were just to bring the bass back up to around -24db.

[snow123]

WAIT NO i just realized i had a 22k resistor in between lugs 1 and 2 of the mids knob and that was what was preventing the midis control from distorting *facepalm*

[snow123]

i just replaced R14s 22k with a 27k and the distortion is gone again! but it just barely boosts the mids lol

[Vivek]

Does one really need that buffer at the end ?

[snow123]

Does one really need that buffer at the end ?

not really lol

[GibsonGM]

R1 and R2 being 22k is the same as if they were both 10k, or 1k     1/2 the signal from the clipping stage is going on to your tone control.
Voltage divider output is:    Vin (R2/R1+R2) = Vout     
What changes is the current in them, and the loading that can cause. In this case I don't think it matters.

R1+R2 are the 'volume control' that determine if the 'tone' and mid control clip.   If the signal is too hot there, it will.


Remove output buffer, make R8 the 100k pot. Move the 100n output cap to the output of U6 before that pot.  Simplify this.

What happened to the original mid control?  Pretend the 'tone control opamp' is the buffer U1.

[GibsonGM]

I might even get rid of the 'tone' control, put the above in there as-is (since we know it works!), and pop a high cut after this just before the volume control.

In fact, you could incorporate our own Mark Hammer's "SWTC" with the volume pot and take care of that nicely, I'd think.
Some variations here:

http://www.muzique.com/lab/swtc.htm

[snow123]

I might even get rid of the 'tone' control, put the above in there as-is (since we know it works!), and pop a high cut after this just before the volume control.

In fact, you could incorporate our own Mark Hammer's "SWTC" with the volume pot and take care of that nicely, I'd think.
Some variations here:

http://www.muzique.com/lab/swtc.htm

idk about that since im really happy with the way the tone control is rn.

[iainpunk]

how about you try putting the volume control before the mid and treble control? lowering the signal hitting that opamp would also lower the clipping and distortion.

cheers

[snow123]

Remove output buffer, make R8 the 100k pot. Move the 100n output cap to the output of U6 before that pot.  Simplify this.

i just tried it without R8, and it distorts without it.

[antonis]

Without R8 both amps are biased at ground potential..
(or +9V if R8 is shorted..)

[snow123]

tbh im pretty happy with how the circuit is right now. now i just need to build it on vero and hope nothing else goes wrong!

here's the layout:

[GibsonGM]

Sorry snow, we appear to have crossed schematics.  I meant for you to move YOUR volume pot, 100k, to where Your R8 is in Your schematic, not mine    In other words, you could eliminate the output buffer to make it more simple. 

MY R8 is required, of course, as part of the power supply! 

[snow123]

Sorry snow, we appear to have crossed schematics.  I meant for you to move YOUR volume pot, 100k, to where Your R8 is in Your schematic, not mine    In other words, you could eliminate the output buffer to make it more simple. 

MY R8 is required, of course, as part of the power supply!

no, i was talking about the 1k resistor that goes before the volume pot on my schematic.