PS Audio BHK Pre Amp and Herron VTPH-2A Phono Pre Users

I just purchased a PS Audio BHK pre amp.  I am moving to the BHK because I need to start using XLR cables for long runs to my power amp.  

When using the BHK with the Herron VTPH-2A phono pre, the sound is flat - for want of a better word.  When I use my Herron VTSP-3A(r02) pre amp with the VTPH-2A, the sound is wonderful.  I'm new to tubes.  I think I have an impedance issue.  Anyone else using a Herron phono pre with a BHK pre amp having or had a similar experience.