This code presumably intended to name sources "foo%a", "foo%b" etc, but
since it was incorrectly appending the character as an integer sources
instead ended up being named "foo%97", "foo%98" etc.
Also changes the branching logic to use this branch upto 26 channels,
rather than just upto 25 channels, as that seems to have been the
intention.
8810c36c6e