Thank you for your reply. Currently ( not wishing to cause conflict as your experience and your system YMMV ) I have a GSX mk2 but oddly I found the GSX slightly less transparent ( small margin ) no extra brightness but more musical than stand alone Dave.... I guess the extra power and headroom helped with the LCD4 I currently have. So I will give the Dave - GSX Mk2 another listen in the next few weeks.
So I guess with the Phonitor X ( or XE my preferred ) will be warmer than my current set up which answers my question, Thank you.
Sorry, it looks like I cut-off the end of my 2nd sentence, which should have read: "Transparency was similar to, if not a perfect match for, the Phonitor X".
The Phonitor X is still the only solid-state amp where I can't tell a difference in transparency vs. DAVE's direct output.
I don't think I tried my LCD-4 in a GSX Mk2 vs. DAVE-direct comparison (don't have any notes on that combination). Before I got to doing so I'd already decided I wasn't going to go with that amp due to not liking the 24-step volume control so further testing wasn't useful. I don't care for my LCD-4 straight out of DAVE, though, and via my Phonitor X they definitely exhibit a more impactful and controlled bottom-end than vs. DAVE on it's own.
I don't know if the Phonitor X will actually sound any warmer than the GSX Mk2 with the LCD-4. That the HeadAmp was a little brighter with the Abyss and Utopia may not translate the same way to higher-impedance (or even just "other") cans. But, again, once I was off the idea of having one I didn't listen further.
It's worth noting that, with DAVE specifically, the 24-step attenuator is not an issue, since you have much more granular control on DAVE itself. But for my purposes, the amp wasn't just going to be used with DAVE, so the limited granularity of the stepped attenuator didn't work for me.