Yes, definitely so. Could you post your findings, as it would be useful. I found it difficult to do decent listening tests as I found it hard to keep swapping inputs and keep my concentration up. By Swapping I mean taking the high level leads off the amp completely.
In the end I settled for perception, and I perceive the low level inputs to be much cleaner, even if I am scientifically wrong. May be the signal from the pre-out is the cleanest signal path - dunno.
The bass from the sub seems more detailed as well, but again may be due to imaginary tone control.