Apart from the fact that you can change cycles on the fly using CTRL+F11/12, for me after a normal install of v0.74 in the default path it's situated in
\Users\<user name>\AppData\Local\DOSBox

You really couldn't find it searching for dosbox*.conf? Strange. Search is smart enough to find it even if you search for the wrong "dosbox.conf" filename.

found it:

I did the search directly in the C folder
and the path is different from what you said

this is the path he was in:
C:\Users\<user name>\AppData\Roaming\AppClient\Dosbox1
and the AppData Folder was hidden

in the path you said there was another file:
C:\Users\<user name>\AppData\Local\DOSBox\dosbox-0.74.conf

witch one I need to edit?

The Local one should be the correct one.

thanks