# Small Fry/Tater Tot EQ circuit function



## Devoureddeth (Jul 15, 2019)

Wanting to adjust the EQ of the Small Fry for bass just not familiar with the EQ circuit so I am not sure what to search. If anyone know what to call this or is familiar with how the the bass, mids, and treble control works it would save me a lot of random breadboarding. Schematic here https://www.pedalpcb.com/product/tatertot/


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## Nostradoomus (Jul 15, 2019)

What do you want to change about it? Make it more bass frequency friendly?


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## phi1 (Jul 15, 2019)

Tone control is just a simple RC low pass filter where the pot changes the R and thus the cutoff frequency. You could change C5 so that the tone pot works over a different range. 

I'm not familiar w that exact setup for bass and mid, but it seems like changing C8 an C9 would adjust the frequency of those bands. 

There is a bass cut pre-clipping (like most opamp dirt pedals) that depends on the pres knob. Increase C4 to get more bass there. 

You could always populate the PCB and put sockets for those caps and experiment that way.


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## Nostradoomus (Jul 15, 2019)

I’d put 100n for an input cap too


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## Devoureddeth (Jul 15, 2019)

I have a Deep Fryer so I already have a bass friendly version just trying to incorporate the additional Small Fry controls like presence, treble, and middle. There is no schematic of the Deep Fryer yet but it is close to the Small Fry.

Yeah it looks like it adjusts those frequencies I am at a loss as to what to look up to understand that bit better. I probably end up plugging and playing. I was wondering if their was a calculation to figure out the frequencies each control alters.


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## Nostradoomus (Jul 15, 2019)

http://www.learningaboutelectronics.com/Articles/Low-pass-filter-calculator.php Is a pretty great read (with calculators)


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## Devoureddeth (Jul 15, 2019)

I figured it was probably just a filter of some sort this useful thanks!


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## phi1 (Jul 15, 2019)

Tone control is passive low pass like the link above, R is adjusted by the tone knob. 

Shape and presence are high pass filters (oddly enough the formula for the cutoff freq is exactly the same as the low pass). Again, the trimmer position changes the R, and thus the freq. In this position the R also affects the gain. I forgot in my other post, C3 could be experimented with too (increase for more bass). 

I recommended it somewhere else, but the electro smash articles are really helpful, like the Tubescreamer or rat. It's a lot to digest, but mainly focus on the gain and tone stages.


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## Devoureddeth (Jul 15, 2019)

Yeah I like their articles, I am DOD 250/Disto+ a RAT circuit for shits n giggles after reading about both the Dist + and Rat circuits. It won't do anything fancy but it should be cute.


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