Myths, tricks and hey, that's neat!

[ejp]

It is billed as bass boost , but from what I can tell it actually attenuates the higher frequencies, not boost the lower ones.

Same difference. It’s a low-pass filter with a shelf. It is the 3180-318uS part of the RIAA filter.

 

[rayma]

Here is a bit better exposition of the basic feedback topologies.
https://www.electronics-tutorials.ws/systems/feedback-systems.html

 

[MarcelvdG]

So , to understand the voltage controlled current source designation could I say that any circuit over which a change in voltage results in change of current fits that name?

A voltage-controlled current source is a network-theoretical element, it doesn't exist in real life. It has an output current that depends only on the input voltage and the gain (called transconductance or transadmittance) of the controlled source, and it has a zero input current.

The trick is to replace it with some circuit that does exist and that approximates this behaviour well enough for the application. It turns out that just about anything that linearly converts voltage into current is good enough for the feedback network of an amplifier with shunt-shunt feedback, even just a plain old resistor.