low pass filter for DSD

Ah, I see. What kind of circuit drives your filter? What is the HF behaviour of your tube stage?

I don't know the HF behaviour of the tube stage, the tube stage to be used in attached pic.


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Butterworth or Chebyshev would be fine - I suggest Butterworth as its simpler to design. The corner frequency depends on you - perhaps 50kHz -3dB would be fine as a first attempt.

A 4th order LC would have two series inductors and two shunt capacitors, followed by a resistive termination

<edit> Attached a schematic based on a design I did for an ESS DAC. Its Butterworth but 30kHz -3dB.


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What Low pass filter: Butterworth or Chebyshev?

What is more important for you - steepness of the filter, or minimizing ripples?

What is the corner frecuency necessary?

As low as possible - I would put it at 22-25 kHz.

What kind of filter: series or shunt?

When you go beyond a simple first-order RC filter, it doesn't really make sense to talk about a series or shunt filter - if you implement the filter as a passive filter, it will have both shunt elements and series elements, and be a fairly complex filter with both inductors and capacitors - and making a 4th order passive filter is not easy! Usually some active buffer elements are used.

If you want to go ahead anyway, all the required formulas are here and here.
I don't know the HF behaviour of the tube stage

I am all for experimenting, but I have to ask what it is that you are hoping to accomplish? You are not likely to produce anything that has superior sound quality compared to systems designed by professional designers, and there is a real risk of burning out your tweeter or causing some other damage to your speakers.