CJ Premier 17LS2 vs ET5/7

Hi,

I enjoy a Conrad Johnson Premier 17LS2 that is paired with a McCormack DNA 500 and Thiel CS5 speakers.

My problem is that the 17LS2 has an output impedance that can rise to 1600 ohms on the low end. The DNA 500 has an input impedance of 10,0000 ohms so I suspect that I am missing the last bit of bass. 

When I listen to other preamps with a lower output impedance, the bass goes a bit lower, but I sacrifice musicality and nuance.

My thinking is that, if I like the CJ sound, an ET5/7 with 100 ohm output impedance would get me that last bit of bass without losing the musicality and nuance.

Has anyone listened to these preamps and can tell me how the ET5/7 sounds compared to a 17LS2?

Thanks for listening,

Dsper