Available as an assembled Module and as a DIY project.
This Module is currently available.
The 73P is an authentic, complete adaptation of the vintage 1073®* mic preamp circuitry to the 500-series format. The 73P is authentic in that it uses only components that are hand-selected to match the original, and there are no changes to any of the preamp circuitry. The 73P is complete in that it adheres to the original, three-stage amplifier design. Many current preamps that claim to replicate the 1073® use a two-stage design, which does not have the same character.
https://www.diyrecordingequipment.com/products/73p-class-a-mic-preamp