setting freq of tone controls TDA7440 and other simular chips

[eef]

I am a newbie here 🙂

Question: How to calculate capacitators for changing freq of tone controls.

And searching for some way to build a nice preamp for double bass.
I have a jfet high impedance input
Also planning to use ICEPOWER as power amp.

But now the in between. Thinking about a chip amplifier TDA7440 or better, so I can control the amp with arduino or otherwise.

Now I want to change the control of the treble + bass controls. THere is a formula for that. But that is above my possibilities, so perhaps there are some examples, calculators etc. to work with. Other tips also welcome.

Regards, Eef

 

[Pano]

Welcome to the forum
Is this a rig for a musical instrument? If so, I'll move it to that section.

 

[eef]

Yes, it is. But these chips are also use in several other audio-concepts.
Please place it where we get the best answers 🙂
Regards, Eef

 

[Mooly]

The TDA7440 is quite a complex chip although it seems to operate in the analogue domain but with digital control...

Have you looked at the data sheet which seems to show how to alter the tone stages.

TDA7440

let me think where would be best for this.

 

[Mooly]

Moved to Analogue Line Level... for now 😉

 

[eef]

Yep, I read that "The treble stage is a high pass filter whose time constant is fixed by an internal resistor (25KΩ typical) and
an external capacitor connected between treble pins and ground."
In the sheet they use 5.6 nf and then the freq = 4-5 khz

 

[Mooly]

The formulas for the bass section look a bit scary but ultimately I think all you have control over are the turnover frequencies, in other words at what point in the spectrum the controls operate.

I would say trial and error might be as good as anything, at least to gauge the effect and how it actually sounds in the real world.