Switch one or more AMS-lite or 1 to 4 external spools with one-or more A1 or A1mini
A 90 degrees turn does the job.
Based on a question and with the help of EricDeNice.
It uses the standard filament hub.(Added:) The clip must be removed, by turning it.

July 2024 The beta test is over.

This is an extended beta testing. Make your own evaluation and use at own risks.
No representation is made that it will fit your requirements, nor that the project will be continued. I have no relationship with Bambulab.
Please only submit comments that can improve the project.

Installation: remove 2 screws, install the "support", do not overtight the screws. Slightly longer screws can be envisaged.
The delicate square locking ring of the filament hub is no more used. Take it off by a smooth turn.

The locking ring can be printed in 2 colors if desired, this is just for fun.
An hook is provided to separate tubes and electric cable, for an easy switch.
And a cap to protect when not in use.

The device is also very easy to access in case od filament broken.

Printing:
Use minimal tree supports.
My test parts were printed with PLA in 0.2mm layer, standard walls and filling, but you are free to improve.
Notes:

• The spring must be kept in place in the extruder block.
• This device makes also interventions in the extruder block easier (e.g. filament broken)

Hook3 has a better grip when using only one PTFE (with multiple PTFE tubes, the hook is simply inserted between the tubes that are held together by the "flower" piece (Note: the electronic cable must be separated from this flower to ease the switching).

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News October 29,2024:

I am using this adaptor for 6 months now. Fast switching from the AMS-lite to an external spool, never playing with the PTFE tubes, fast access inside the head if needed. Just a charm!

PS: remember to remove the small square ring, and keep the spring inside the head. Refer to the pictures.
The 'AMS' letters should be visible in the block part window.
Note that one (or more?) additional filament hub(s) should be purchased from Bambulab.

Bambulab info (Filament hub cleaning)
https://wiki.bambulab.com/en/a1/maintenance/filament_hub_cleaning