Is there any 'scientific' reason that may suggest a high powered valve/ tube combo might be inherently more nosier (hum. buzz) than the equivalent head/ cabinet set up?

I'm probably barking up the wrong tree, but it seems possible that the close proximity of power tubes and speaker magnets in a combo could potentially cause some problems.

Any truth in this?
Thing is, most tube amps are more expensive and generally higher quality than solid states (obviously they're mostly seen as budget amps), so it'd be difficult to get an objective comparison. Interesting question.

EDIT: Missed the point completely, sorry.

Yes, combos tend to be a little noiser, mostly due to tube rattle.
Last edited by kyle62 at Feb 2, 2012,
Are we talking about the same model amp here? i.e., Mesa Mark V combo vs. head?
Gibson Les Paul Studio
Highway One Telecaster
Dean Evo
Mesa F-50
Laney GH50L
Vox AC30 C2
Ampeg V2