# Informant Filter mods, less highs?



## Allthumbs (Dec 12, 2019)

what can be done to get the high roll-off to happen somewhere about noon?  right now I have the filter cranked to the right to get a minimal amount of high roll-off but I find that many amps need it to happen sooner, or to get a bit more roll-off than is available.  

in short:     it's a bright pedal.


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## Nostradoomus (Dec 12, 2019)

Socket your 1k5 resistor and 3n3 cap after the tone control and play around...it’s the tonestack from a RAT.


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## phi1 (Dec 12, 2019)

The A sweep on the cut pot means the sweep will be gradual and then drastic at the end. You could change it to a B (linear) 100k pot.

otherwise, I agree with @Nostradoomus, play around with those components. Look up info on the rat circuit (electro smash has great articles) or about RC filters in general.


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## Chuck D. Bones (Dec 13, 2019)

[UPDATED 12/30]
Not so with the Informant.  The CUT pot is wired for brightest tone at zero, darkest tone at 10.  As-designed, the CUT control ranges from 475Hz to 32KHz.  You can bring the entire range down by increasing C8.  6.8nF would be a good start.  Or you can leave the bottom end of the range at 475Hz and just bring the top end down by increasing R11.  3.3K or larger would be appropriate.  If R11 is less than about 10K, then stay with A-taper for CUT.  If you increase R11 beyond 10K, then B-taper will have a better feel.


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## Allthumbs (Dec 13, 2019)

thanks, all.  will try the pot then the board parts


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## Ktid (Dec 30, 2019)

Chuck D. Bones said:


> Agreed, the CUT pot should not be A-taper.  As-designed, the CUT control ranges from 475Hz to 32KHz.  You can bring the entire range down by increasing C8.  6.8nF would be a good start.  Or you can leave the bottom end of the range at 475Hz and just bring the top end down by increasing R11.  3.3K or larger would be appropriate.  If you leave R11 alone, then go with C-taper for CUT.  If you increase R11, then B-taper will have a better feel.


I am piggybacking this post, but if you change R11 to resistor higher than 3.3k is the change in potentiometer required?


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## Chuck D. Bones (Dec 30, 2019)

I had to go back and edit my comments from 12/12.  On review, I see that the CUT pot gets darker as you turn it clockwise, like the Rat.  If R11 is below 10K, then A-taper will be fine.  For reference, a 100K A-taper pot will be 15K at noon.  The top half of rotation will span the remaining 85K of resistance.


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## Ktid (Dec 30, 2019)

Chuck D. Bones said:


> I had to go back and edit my comments from 12/12.  On review, I see that the CUT pot gets darker as you turn it clockwise, like the Rat.  If R11 is below 10K, then A-taper will be fine.  For reference, a 100K A-taper pot will be 15K at noon.  The top half of rotation will span the remaining 85K of resistance.


Awesome man, thank you!


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## seiche (Apr 16, 2020)

I like doubling the 220nf cap (on a switch) or substituting 470nf. Makes the whole range of the cut and drive knobs actually usuable for me.

Stock is way too bright and brittle. This is subtle but effective (and easy).


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## jubal81 (Apr 16, 2020)

seiche said:


> I like doubling the 220nf cap (on a switch) or substituting 470nf. Makes the whole range of the cut and drive knobs actually usuable for me.
> 
> Stock is way too bright and brittle. This is subtle but effective (and easy).



Do you use the pedal more for high gain or low gain? I haven't built this one yet, but I get the impression it's tuned to sound best on lower gain settings. More gain means more harmonics and IM distortion on the high end. Curious if you use the extra filtering on a switch to compensate for high gain use.


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## seiche (Apr 16, 2020)

I like it better for both but especially for low gain as there are more bass freq coming through


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## phi1 (Apr 16, 2020)

A similar mod would be the voice knob I put on my build (I did a bass knob first, but changed to voice knob later). Similar in that it changes the frequency of the high pass filter (bass cut) before clipping. Different in that the voice knob also affects gain, whereas the capacitor switch doesn’t affect gain. A bonus for the knob is that they are often easier to fit into a build since they fit more comfortably than a switch under the pcb (especially for 1590B). 






						1981 DRV (Informant)
					

Here's one I finished a few days ago.  I don't normally post my vero builds here, but my understanding is that @PedalPCB gets credit for the trace they used on the tagboard site.  Why did I go to the trouble to build it on vero instead of use the easy pcb here?  I like to try to fit any pedal I...



					forum.pedalpcb.com
				




I prefer voice knob up for higher gain (tighter bass), and lower voice knob for lower gain settings (more bass through like seiche said). but voice low and high gain can be nice and thick sounding too. 

Chuck graciously ran some simulations In that thread of the voice knob vs bass knob vs some other mods.


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