@tobi
There is some overlap with the filters here as ‘Preamp’ also includes patching (but patch does not include preamp).
This is because the preamp settings can be stored with a channel, but they control an analogue preamp which exists at each socket which can also be controlled from the I/O screen independently of the channel.
Preamps not connected to input channels can be used with tie lines for recording or sending on to other systems.
If preamp changes on the input channel are blocked but the patch is allowed to change, then the question is which preamp setting should be used?
You could for example, instantly apply phantom power to a socket, or lose the gain settings of the preamp which may have been set for the next band on in a festival situation, or mess up the signal level going to another console…
There is some discussion about whether this is all acceptable however, so although the input channel patch library is designed for what you want to achieve here, if there are other examples where you need this to be separate, please do say!
Cheers,
Keith.