I agree that switching between an AM and an FM station, as well as switching between the radio and MP3s, tends to have significant volume differences.

I think what happened was that the empeg guys tested this out and adjusted it to what they thought sounded good. But perhaps English radio stations do things a little differently than US radio stations.

I think this is similar to the bass boost on the tuner. The empeg guys got it sounding right for the radio stations in Cambridge. I think the bass boost sounds PERFECT for all of the AM radio stations I can pick up here, but it's too much for FM radio stations here.

I think it would be nice if we could adjust the global volume offset between FM, AM, and MP3. I also think it would be nice if we could select the bass boost to be on or off for FM and AM independently.