Herron VTPH2 new in system

I just bought a Herron VTPH2 in part just to see what all the fuss is about. My question has to do with system synergy.

Upstream I'm running a Phasemation MC cartridge into a SUT into the Herron. Downstream the Herron's connected to the tape input of the Precision Fidelity C7A Revised that it may be replacing. That unit is a passive pre with a tube phono stage that's now bypassed. Downstream, is a Rogue Atlas Magnum amp driving One Thing rebuilt Quad ESL57's.

There's nothing really wrong with the system as it was- very enjoyable, given the known limitations of the Quads, which I accept as a trade-off for their incredible strengths. The Herron's an experiment.

I've only spun a few records so far. Here's the good- the Herron's very revealing and musical. I'm not a soundstage nut, but the Herron spreads instruments out on the L-R spectrum amazingly. I get a strong sense of why people rave about it.

The bad- where'd the bass go? There's much less flesh on the bones of the music. I know my system tends to favor midrange/treble as it is, but I didn't expect such a further push in this direction. The big test was Beck's Morning Phase LP- its bass has overwhelmed me in previous system iterations- a lot of the choices I've made have used this disc as a guide to bring such bass energy under control. But with the Herron inserted, while I can hear it as an instrument, just about all the lower fundamental frequencies are gone. Also, I keep turning the volume up to hear what I think I should be hearing- the music just feels "held back" somehow.

I infer there's a serious mismatch between the Herron and the passive stage of the PF. Before I test this with a spare old Belles preamp I've got laying around, any wisdom out there? There's an old, slightly banged up Herron line stage hanging around out there for $850 that looks tempting . . . after splurging on the VTPH2 I'm not up for going all out on a line stage.