Filtres TAD/Kinoshita pour TSM et TSM like

[marco_gea]

OK, I think I got it now.

The 'PC' capacitors in the HF section of the filter are probably all the same value, i.e. 10uF, except for the little one at the far left.

So here are the revised values:

High-Pass Horn (2nd ord. Q = 0.9 @ 1.31 * 650 = 850 Hz)
C1+C2+C3 = 10+10+2.2 = 22.2 μF; L1 = 2.7 mH

Fixed L-Pad (-10dB)
R1 = 5.6 Ohm; R2 = 3.3 Ohm

parallel RLC (equaliz. horn)
C4+C6 = 10+10 = 20 μF; L2 = 0.2 mH; R3 = 3.9 Ohm

series RLC serie (impedance comp. horn)
C5 = 10 μF; L3 = 1.1 mH; R4 = 22 Ohm

Et voilà!

Funnily enough, the high pass value now give a 'textbook' electrical 2nd order Butterworth high pass at 650 Hz into 8 Ohm! Ha ha ha...

And the low pass section is also an almost perfect electrical 6th order Linkwitz-Riley low pass at 650Hz into 8 Ohm!

So it really just seems as if the TAD designers just started with two 'textbook' electrical sections, and then tweaked them a little bit till the summed response was to their liking.
But really, most of the tweaking boils down to just the HF RLC contour network to flatten out the mid-range hump of the TD-4001+TH-4001.

OK, as far as I'm concerned, the case is closed.

Cheers,
Marco