I noticed that in early Fender amp designs, such as BF princeton, BF deluxe, even earlier tweed models, feedback the output of some of the gain stages back to the input of the 2nd gain stage. Newer designs, such as the Blues Deluxe, do not do this. Can someone comment on the pros and cons of these different approaches in the pre-amp gain design? Is either superior for any tonal reasons? Etc.