I thought I'd mention my experience with my ZROCK2 and CSP3 for those who might wonder if one or both are needed.  I was using the ZR2 after my CSP3 and I really liked the additional weight the ZR2 brought.  I am sending my CSP3 in for service though and I now just have the ZR2 in the chain.  It turns out that I can't tell a difference with the CSP3 gone other than a loss of gain which isn't an issue since I can still bring the amp up to clipping.  The one difference is that now I have to dial in more of the ZR2.  For example, if with the CSP3, I would set the ZR2 at 2 o'clock, without the CSP3, I have to set the ZR2 at 3 or 4 o'clock.  So, if I were doing this over, I'd start with the ZR2 before automatically going for the CSP3.  That said, I like what the CSP3 brings to the table in terms of flexibility, but it might just be the icing on the cake.

The ZROCK2 is pretty astonishing and does work well on its own. What it does with the tonality and the "heft" is special and can make a system really shine.  I'm spoiled though. . . the ZTPRE allows me to connect three sources via balanced outputs and makes all my sources sound BETTER without sounding as if there's another component in the mix if that makes sense. And the ZBIT feeding the ZROCK2 from the ZTPRE is the icing on the cake. Talk about gain flexibility. . .I can adjust gain at the ZTPRE, the ZBIT and the ZROCK (not to mention at two of my sources). This is the best my system has ever sounded and I'm so so happy.

Something interesting happened after trying the direct to ZR2 minus the CSP3 that I thought is worth sharing...

Next day I came down with a massive sinus cold so I thought I would check the forums as I could not do much more.  Artem posted about the 6N5P and as I have the exact ones he tried I thought I would give them another listen, by this time the CSP3 was back in the mix.  

Turned everything on and the volume was no where near what I’m used to.  Checked all the settings and had a hard time getting the volume up even when everything was cranked.  In frustration I even flipped the Hi/Lo impedance switch on my UFO2 to the back position and things improved and not just in volume, although the volume was still not as before.  So I gave up for the day.

Next day I was feeling much better and tried again at the previous days settings.  The volume now just about blasted me across the room. Turns out that I didn’t take into account just how congested I was and to what degree my hearing was affected.  I’m a lot smarter than this and would consider the fact that I had this massive cold so why didn’t I?  In my defense the only possible reason for the above is that some practical joker switched my Cold & Sinus pills with Stupid pills.

Anyway, I did notice that the Hi/Low impedance switch set at the rear position on the UFO2 and the ZR2 set at about 2 o’clock instead of 3 o’clock yielded greater detail, density and tighter bass.  So for those of you who have the ZR2 and the UFO try flipping the Hi/Lo impedance switch on it, you never know.

Still like to get my hands on the bugger that switched my pills.