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

Started by snow123, December 06, 2021, 05:24:00 PM

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snow123


Vivek

Gyrator based mid with fixed F and Q can also be one knob.


Vivek

If you dont mind dual pots

Here is a mid boost, fixed gain but variable frequency, before a clipper

https://www.dirk-hendrik.com/temp/ibanez_st9.pdf

Vivek


Ben N

Quote from: antonis on December 07, 2021, 07:40:47 AM
Quote from: Ben N on December 06, 2021, 06:31:39 PM
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...!!! :icon_mrgreen:
If you insist, although these are all over the internet. But I draw the line at schematics.

Ignore everything below the dotted line.
The schematic at Aion (Fractal project) is cleaner, but it's only as part of the build doc pdf. Also note that it does require a 100kC dual pot. At the moment I can't recall where I sourced that, but it might have been Small Bear, so that's not too encouraging. But the drive section is a fairly generic non-inverting op-amp soft clipper, so it would seem that the frequency boost (and cut) section could be grafted into most any overdrive, or even be boxed up separately.
Edit: Come to think of it, it's essentially the same as the ST-9, at least in terms of the variable mid boost, except that the OD-05 let's you mix the mid-boosted signal with clean going into the clipping stage, while the ST-9 gives you a post-clipping tone control.
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iainpunk

wait, do you want to boost AND cut, or do you just want to cut the mids?

if yo just want to cut some mids, i suggest adding a bridge-t filter like this one


the values are set up to scoop around 1300Hz-ish but you can easily change them to two 10k resistors, a 10n on top (bridge capacitor) and a 100n on the ''leg'' of the filter. this gives a 500 Hz filter

cheers
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers

GibsonGM

#27
I posted a link to an article that talks about exactly that, near the beginning... :)   Both types of mid control are viable; yours probably has less insertion loss, Iain...and may be the better choice IMO. 

Mod 5: https://www.premierguitar.com/videos/hooked/deerhoof
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niektb

Quote from: iainpunk on December 08, 2021, 09:54:57 AM
wait, do you want to boost AND cut, or do you just want to cut the mids?

if yo just want to cut some mids, i suggest adding a bridge-t filter like this one


the values are set up to scoop around 1300Hz-ish but you can easily change them to two 10k resistors, a 10n on top (bridge capacitor) and a 100n on the ''leg'' of the filter. this gives a 500 Hz filter

cheers

I used a Bridged T to cut at 400Hz in the past and while that works wonders for bass, I rarely ever touch it for guitar... :(
But maybe at  the 700Hz it's useful :)

iainpunk

my pedals are full of bridge T filters, all over the frequency spectrum, with different purposes in mind. if you place such a filter in the feedback loop of an opamp it can even boost the frequencies it cut before.

cheers
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers


snow123

Quote from: iainpunk on December 08, 2021, 09:54:57 AM
wait, do you want to boost AND cut, or do you just want to cut the mids?

if yo just want to cut some mids, i suggest adding a bridge-t filter like this one


the values are set up to scoop around 1300Hz-ish but you can easily change them to two 10k resistors, a 10n on top (bridge capacitor) and a 100n on the ''leg'' of the filter. this gives a 500 Hz filter

cheers
i want to be able to boost and cut the mids. like the knob at noon would be how it is stock, then i'd be able to cut or boost the mids.

snow123

Quote from: Vivek on December 08, 2021, 07:37:49 AM
and here is a gyrator one knob mid control after clipper

Fulltone Secret Freq

https://www.pedalpcb.com/docs/Arcana.pdf
ok, so how would i go about adding that kinda thing to what im building?

Vivek

While connecting up one part from one circuit to another part taken from another circuit, we need to check


Supply voltages match
Impedances match
Bias match
Signal level match


Please post a proposed schematic of existing circuit + new part taken from other circuit, and the lovely people will check out the compatibility and interconnection between the two

snow123

#34
heres the schematic i drew up in DIYLC. i just took the mid control from the seymour duncan 805.



iainpunk

you might want to lower the 100k pot, otherwise, it wil do a lot of nothing in the middle 90%, and go from a little to a lo in the last 5% on each side.

cheers
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers

snow123

wait what will increasing/decreasing the values in the gyrator mid control do?

GibsonGM

Do you use any simulation software, Snow? Like, LT Spice or Tina TI?  (both free).  You can model this stuff, and see what those changes do!  ;)   
Per Iain, I'd lower the 100k pot to 10k.

And check out LT Spice or Tina TI....you'll want to start messing with 1 or both since you'll be addicted to this hobby, and will want quick answers to this stuff on your own!
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snow123

Quote from: GibsonGM on December 09, 2021, 04:13:24 PM
Do you use any simulation software, Snow? Like, LT Spice or Tina TI?  (both free).  You can model this stuff, and see what those changes do!  ;)   
Per Iain, I'd lower the 100k pot to 10k.

And check out LT Spice or Tina TI....you'll want to start messing with 1 or both since you'll be addicted to this hobby, and will want quick answers to this stuff on your own!
lol im actually messing with ltspice rn

GibsonGM

Cool...maybe mock it up in there, and see what you come up with?  Yes, you can alter the cap values and so on to move the freq. around.  Getting a 'hump' AND scoop becomes more of a problem, tho, IIRC.   That's more of an 'active filter' kind of problem.  You'd end up with a TS on acid, lol.

If you get going in LT and have questions, many of us use it so you will get a lot of help.  You might even post something in the 'Simulation' section, that isn't very busy and it'll give everyone something to do!  :) 
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MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...