Mark, The effect of the LF Extend and HF Attack filters was very apparent. I suspect that the HF Attack would be useful when using a cab. I think subtleties like 'feel', responsiveness and compression would be much more apparent to the player. I did not think there was anything in your recordings with enough level to cause compression (or audible harmonic distortion). At this point I kind of favor the Zephyr because of its flexible EQ and minimal voicing when adjusted flat - I like to make my own EQ adjustments - no need for voicing. Along those lines I would be curious to know if the other pre's can be EQ'ed to sound like the DTI?