jea48, i think you made a mistake on those grey plate Siemens CCas. If you take a closer look, those are the silver plates or shields. You can see on the nearer tube where the shield is pinched (below the final s in Siemens) that it is clearly a shiny metal. That is what you don't want. Another indicator is the aluminum tag with the tube codes stamped on it above the silver shield. These are later vintage tubes and are supposedly (I've never compared them) brighter and poorer sounding in general than the grey shields. The grey shields have the codes etched into the glass like other Phillips tubes.
That may be the OP's problem. If he got a pair of these instead of grey shields he would probably be disappointed.
That may be the OP's problem. If he got a pair of these instead of grey shields he would probably be disappointed.