Angry Beard III Electric Guitar Effect

The OP-AMP can be any single low noise op-amp, the original NE5534 used. The 2N44 is likely to be replaced by PNP germanium transistors other without much change in sound. The switching aspect has been omitted from this diagram, but you probably want to add a bypass of some types to this effect.

This emphasis switch chooses a tone flavor, this could be expanded to include a wider range of frequencies, but too small a capacitor value may cause oscillation.
All tame a company internal confirmation of this effect has been omitted, but it would be easy to add. This can be noisy, depending on the platform, so that the capacitor with value 10-15pF  could be placed in a cycle of OP-amp if you are worried too much squeaking.