Tonestack Components Values

Stompboxes circuits published in magazines, books or on DIY electronics websites.

Tonestack Components Values

Postby POTL » 17 Sep 2017, 13:16

I found the information that if you reduce the resistor values ​​by 10 times and increase the capacitor values ​​by a factor of 10, the noise in the circuit decreases.
Tell me how much this information is correct?
Does noise only come from resistors or potentiometers too?
Is there any meaning or difference that will not be noticeable?
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Re: Tonestack Components Values

Postby deltafred » 17 Sep 2017, 19:31

That is correct.

All resistive devices generate noise, the higher the resistance (and voltage IIRC) the higher the noise figure. It's a long time since I had to learn this so rather than get it wrong I will leave it to the younger guys who can remember the theory better than I can.

The drawback of using lower value resistors is that it will load the circuit that is driving it more so you will need either a lower impedance buffer to prevent the signal being attenuated too much, or feed it with a larger signal, or add a make up gain stage after it.

All 3 methods need additional gain (the first current gain to lower the impedance, the other 2 voltage gain) and will add noise. Also the make up gain stage will amplify any noise generated by the tonestack.

As you can see getting the lowest noise is a balancing act. It requires quite a bit of trial and error or a whole lot of maths (and a good understanding of electronics helps as well).
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