Clever passive tone stack slipped into the feedback path?

[Electric_Death]

Came across this at DIY Audio, am I interpreting this properly because to me it basically looks like a passive tone stack slightly modified and slapped on the feedback path of an active boost stage:


I realize plenty of "active" EQ's out there will be nothing more than a passive stack placed post gain stage but I've come across several designed like this, many of which were for hi fi use though this one did in fact come from a pedal.

[R.G.]

There's a lot of background reading you need.

That's the classical feedback form of the Baxandall tone controls. It's worked over in great detail for a three band setup like that in the "Tone Controls" section of the National Semiconductor Audio Applications handbook.

That circuit is a development of the treble/bass shelving equalizer from hifi work. Baxandall developed the earlier form for hifi.

[Electric_Death]

Well considering that I knew it was hi fi based without anyone telling or hinting to me, I think I've been doing pretty well without retracing the steps of others