I hope it has a very good tuner that is not overly sensitive to amplification and overload.
Amps & especially preamps are subject to overload.
TheCM-7400 is very problematic in this regard, and very aggravating, as certain distant channels require the use of a preamp.
Sounds like either the tuner isn't as sensitive, or it doesn't have as good of a error detection/compensation of the others.
Do you have close, local stations that might be overloading your preamp (assuming you are using one)?