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

[snow123]

hello, how can i add a mids control to a tube screamer? I'm building a tube screamer clone that is supposed to work more as a clean boost (so far I've removed C4, replaced the clipping diodes with red LEDs, replaced R6 and the 500k drive pot with a single 68k resistor, and I've replaced R4 with a b10k pot to function as a bass cut control). And I have tried replacing R7 with a 5k pot wired as a variable resistor, but that just seems to work more as a presence control (which is not what i want), and it got super noisy and super bright when i maxed out the pot (idk why).

[snow123]

i have also considered replacing the tube screamers tone circuit with the jet drivers tone circuit, but im not sure how i would go about doing that.

[GibsonGM]

The way a TS is designed, it doesn't really 'make' a mid hump.  It has a low cut, and a hi cut, which leaves the mids 'over-emphasized' - to some.  I like it for blues, but anything else, meh.   There are variations on this theme, some Wampler stuff and others, that eliminate that.  But then - it's not a Tube Screamer once you mod it that way    

It wouldn't be very hard to design something taking the basic parts of a TS and to incorporate a mid control.

Edit: here, found this...there are others too.  https://www.premierguitar.com/gear/5-diy-mods-to-perfect-your-ibanez-ts9-and-boss-sd-1
Easy esp. on a new build.

If you're doing a 'clean boost'...why are ya looking at the TS?  Why not something like a Mosfet Boost or a Fetzer or something?

[snow123]

If you're doing a 'clean boost'...why are ya looking at the TS?  Why not something like a Mosfet Boost or a Fetzer or something?

i really like using the TS as a clean boost, and i mostly use it (instead of any other clean boost) because of how the tone control cuts the bass and boosts the mids and stuff.
i just sometimes need to adjust how much its boosting the mids and how much low end its cutting out.

[GibsonGM]

Play with the 'mod' they show in that article, it looked like it has promise!    Yeah, for bluesy stuff the TS is pretty good.  I like the "Timmy" version myself ("Timber Booster").   I'd also like to be able to cut that mid back some.  For 'general purpose' boosting, tho, I tend to go to a Mosfet or Fet gain stage, simple and 'transparent'.   Just a matter of taste and what material you're playing!

[Ben N]

As noted above, the TS mid-hump is a function of low & high cuts. Timmy gives you control over those, so you can tailor the shape & amount of mid emphasis, and it does a great clean or near-clean boost with emphasis. Fairly easy to DIY, although they are fairly reasonably priced and readily available, now that MXR is making them.
I just finished a different pedal, a clone of a Pearl OD-05 (Aion pcb) with an interesting approach because it allows you to get anything from extreme, c0cked-wah emphasis over a range of frequencies (if you mounted the frequency pot in a wah shell it would make a decent wah) all the way to scooped tones over the same range. It's a pretty cool alternative to a TS, although it may require a bit of tweaking to serve as a clean boost.

[antonis]

I just finished a different pedal, a clone of a Pearl OD-05 (Aion pcb) with an interesting approach because it allows you to get anything from extreme, %^&*ed-wah emphasis over a range of frequencies (if you mounted the frequency pot in a wah shell it would make a decent wah) all the way to scooped tones over the same range. It's a pretty cool alternative to a TS, although it may require a bit of tweaking to serve as a clean boost.

Schematics, build & sound demos, plz...!!!

[iainpunk]

i know the treble control on a tube screamer is quite close to the treble control in the boss hyper fuzz, and i have done a treble to mid conversion mod to a hyper fuzz clone. basically, replace the cap and resistor thet come of the pot with a daughter board which houses only a gyrator circuit. it now boosts and cuts mids.

a good bit of info in this thread:
https://www.diystompboxes.com/smfforum/index.php?topic=123374.msg1211856#msg1211856

hope this helps,
cheers

[Vivek]

Have you decided if you need mid control before the clipping or after the clipping ?


The Tech 21 Character series have one before clipping. It is just a slightly modified Baxandall mid control. You could use the same before and after the clipping stages

But to make it effective, you need to first remove / modify any mid shaping filters that are already present.

[iainpunk]

Have you decided if you need mid control before the clipping or after the clipping ?


The Tech 21 Character series have one before clipping. It is just a slightly modified Baxandall mid control. You could use the same before and after the clipping stages

But to make it effective, you need to first remove / modify any mid shaping filters that are already present.

this, but to add a mid control before clipping, you probably need a whole extra opamp stage.

if you want a simple mod for more bass and treble, i suggest swapping the 47nF cap coming off of pin 2 and the 220nf coming off of pin 5 of the opamp, this gives more gain to the bass, and less treble cut. this results in a perceived lowering of the mid range

[m4268588]

[snow123]

Have you decided if you need mid control before the clipping or after the clipping ?


The Tech 21 Character series have one before clipping. It is just a slightly modified Baxandall mid control. You could use the same before and after the clipping stages

But to make it effective, you need to first remove / modify any mid shaping filters that are already present.

this, but to add a mid control before clipping, you probably need a whole extra opamp stage.

if you want a simple mod for more bass and treble, i suggest swapping the 47nF cap coming off of pin 2 and the 220nf coming off of pin 5 of the opamp, this gives more gain to the bass, and less treble cut. this results in a perceived lowering of the mid range

yeah, i'd rather just add a transistor stage or something for a mids control. and I dont need to add anything to control the bass or treble, i already replaced the 4k7 resistor coming off of that 47nf cap with a 10k pot to control how much low end is cut off, and im really happy with how that turned out.

[snow123]

Have you decided if you need mid control before the clipping or after the clipping ?


The Tech 21 Character series have one before clipping. It is just a slightly modified Baxandall mid control. You could use the same before and after the clipping stages

But to make it effective, you need to first remove / modify any mid shaping filters that are already present.

this, but to add a mid control before clipping, you probably need a whole extra opamp stage.

if you want a simple mod for more bass and treble, i suggest swapping the 47nF cap coming off of pin 2 and the 220nf coming off of pin 5 of the opamp, this gives more gain to the bass, and less treble cut. this results in a perceived lowering of the mid range

yeah, i'd rather just add a transistor stage or something for a mids control. and I dont need to add anything to control the bass or treble, i already replaced the 4k7 resistor coming off of that 47nf cap with a 10k pot to control how much low end is cut off, and im really happy with how that turned out.

[snow123]

what values would you suggest using for that?

[FiveseveN]

What happens when you turn "bass cut" all the way up?
Hint: division by zero.

[snow123]

What happens when you turn "bass cut" all the way up?
Hint: division by zero.

the guitar turns into a tin can.
well, it will literally turn into a tin can if you increase the 10k pot to 25k, or decrease the 47nf cap to 22nf or 10nf.

[snow123]

Have you decided if you need mid control before the clipping or after the clipping ?


The Tech 21 Character series have one before clipping. It is just a slightly modified Baxandall mid control. You could use the same before and after the clipping stages

But to make it effective, you need to first remove / modify any mid shaping filters that are already present.

after the clipping.

[FiveseveN]

if you increase the 10k pot to 25k

Other way around: lower resistance is higher cutoff frequency. Notice how similar controls (DS-1, Timmy etc) have a series resistor so it doesn't go down to zero.

[Vivek]

If you decided you need a mid control after the clipping

And it will be active

Then we have few choices

A. The stand alone mid control Baxandall

It has very low Q close to noon, and acts more like a volume control, but gets slightly peakier at the extremes of pot travel


Here is one example from ELECTRIC DRUID TOM
https://electricdruid.net/designing-the-hard-bargain-distortion-pedal/

B. Another option could be a parametric mid a la Metal zone

That would be more complicated, but give you more control

I again refer to Tom's web pages https://electricdruid.net/boss-mt-2-metal-zone-pedal-analysis/

C. There are other gyrator based mid controls with fixed F and variable G. Many examples exist on the net. They will remind you of sections of a gyrator based graphic equaliser.

When we add a tone control with boost to a distortion circuit, more often than not, the tone control also clips at moderate to high boost settings. You might like it.

Then again, you might not, in which case you will need higher Vcc for the tone controls.

[snow123]

If you decided you need a mid control after the clipping

And it will be active

Then we have few choices

A. The stand alone mid control Baxandall

It has very low Q close to noon, and acts more like a volume control, but gets slightly peakier at the extremes of pot travel


Here is one example from ELECTRIC DRUID TOM
https://electricdruid.net/designing-the-hard-bargain-distortion-pedal/

B. Another option could be a parametric mid a la Metal zone

That would be more complicated, but give you more control

I again refer to Tom's web pages https://electricdruid.net/boss-mt-2-metal-zone-pedal-analysis/

C. There are other gyrator based mid controls with fixed F and variable G. Many examples exist on the net. They will remind you of sections of a gyrator based graphic equaliser.

When we add a tone control with boost to a distortion circuit, more often than not, the tone control also clips at moderate to high boost settings. You might like it.

Then again, you might not, in which case you will need higher Vcc for the tone controls.

well i just want 1 knob to control the mids, so the Baxandall i guess?