simple and compact ms20 filter

[kragg]

Hello,
I am considering building a two-in-one version of the filter : 2 filters in serial, first a HPF then a LPF (like the original MS20).
But the switch wiring is a bit unusual to me, and i can't figure out how i should wire my " two-in-one version"
I would like IN > HPF > LPF > OUT (so i wouldn't need a switch).
Also, is there any component which i can remove on the HPF board ? And on the LPF board?
Thank you

[cjonesplay]

Check out Ciaran's layout; I think it is better suited for this and he explains it there in detail:)

[kragg]

Hi,
Ah, yes : I see it in the notes, thank you !

I had seen the Ciaran layout previously, and considered building it, but being +/-15V, it involved a 9V>+/-15V daughter board so i went for this layout instead.

By the way, what does the TL074 and transistors do in Ciaran's layout? Is it acting as a buffer?
I'd like to understand why some layouts feature an opamp, and some doesn't...