We know that these preamps use RC5 device 16.
Get IRScrutinizer. On the Generate tab select RC5, enter 16 into the D field and e.g. 0x07 in the F field. Click Generate.
For example Mute = 0x07:
0000 0073 0000 0014 0060 0020 0010 0020 0010 0010 0010 0010 0010 0020 0020 0010 0010 0010 0010 0010 0020 0020 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0010 0020 0010 0010 0010 0010 0BDD
See also
[Link: irdb.tk]; This has some of the functions in Pronto Format.