At this point I am wondering if anyone with a USB audio has tried this yet and if it worked for them. I thought to check where Audible is supposed to work and it appears that more Kindles are supported than I expected. See here:
https://audible.custhelp.com/app/ans...indle-devices/
Since it was Audible support that gave me the missing information to get this extension working it might work on a wider range of devices than I thought. Of course if Audible support varies by device this might not hold.
So anyone who has this working on a non-bluetooth device let me know. If there is a wide enough range I might need to ask a moderator to add additional tags to this thread.
Dave