fastricky, I have never seen a schematic of the Trumpet, but chances are the 12AU7s are not doing any "heavy lifting". Chances are they are used as cathode followers in that circuit. A CF does not add gain; its job is to convert voltage to current or in other words to provide a low output impedance so as to drive downstream components (a linestage most likely). Because the CF does not add gain, it is less likely to color the sound. Now to repeat what I have said here many times before: 12AU7 is not a great sounding tube, no matter how much you pay for them or how exotic the brand. You can usually replace them with 6FQ7 or 12FQ7 (depending upon the filament voltage in the component), which are relatively cheap and to my ears audibly better sounding even as a CF in an output circuit of a phono stage or linestage. That is my opinion based on trials and errors in more than one instance.
