The circuit has remained Revox. What do you want to improve there?
The headphone amp is still one of the best that can be found in a tape machine! The switch-on delay with voltage monitoring is ingenious and has been copied several times by us from revox-online.
Nevertheless, some optimizations have also been made here.
Support capacitors on the ICs, no electrolytic capacitors, bypass capacitors, buffer electrolytic capacitors for the circuit board, current and procurable relays, peak displays on the rotary controls!