what's this

Link to book:
Small signal audio - Douglas Self
amzn.to/3tc83yV

[@anthonyatwork]

MGR: Mirrored & ground-referenced

[@riccardogariboldi8537]

SFBD Symmetrical Full Bridge Driver....professional deformation (working with motor bridge drivers...😅)

[@anthonyatwork]

FDA: Fully Differential Amplifier

[@anthonyatwork]

SGR: Symmetrical Ground-Referenced

[@KIRA_VX]

Balanced Line Driver / Balanced Line Receiver (the other side)

[@hintoninstruments2369]

This is a poor circuit and should not be recommended. The author does not know what ground symbols to use where. Not to be used if you want AES48 compatibility or are sending through a patchbay.

[@Likeaudio]

The circuit is good and very widely used, the illustration has those errors I agree.