Are sealed cabs the choice for a classic tubes head? I am thinking classic SVT, V4, Showman heads. The original cabs for these heads were all sealed, given the available tech in those days... IDK the tech details, but something to do with damping factor, cone control etc. SO... Do tube heads work best with sealed cabs? If so, is it because the speaker cones aren't as free to move in a sealed cab, as they are in a ported design...and tube heads were designed with this in mind? Thanks.