Running DCS Vivladi DIRECT?

Fair point @seigen but the other consideration is level matching with my phono stage. With the current settings the two need the same rough preamp volume settings and so avoid the danger of playing too loud. 

Gain matching across the entire amplification cascade is an interesting topic and one I’ve previously commented on (albeit in the context of phono)

Why do you need to match the output level between your DAC and phono stage? I mean, are you doing on the fly changes between inputs on the preamp while listening simultaneously to your TT and DAC? In that case the Vivaldi would be quieter than your phono stage at the same volume level on the preamp.

The 0.2V setting on the Vivaldi might sound better when run direct into the amps since you'd hardly get to use the volume control at all, keeping it mostly at max.

Why match? To avoid having to remember to add or cut 20-30 steps on the volume control or risk playing way too loud. As it stands the two inputs use the same range which is what I want. Also we want to avoid at all costs using any gain at all in the pre-amp and reducing to 0.2V would mean needing to use almost the full gain stage (12dB) to get 0.7V rated output (not that I of course drive the amps that high but peaks may) while 600mV is much closer to the desired 0.7B output sans gain ... make sense?

In other words the volume control setting and cuts I describe represent the average, the peaks may be close to unity

Plus I should add that the test tone I used for level setting is -20dBFS so if you like the peak you are actually hearing with 14dB cut is +6dB

This all gets confusing which is why I always keep my gain cascade spreadsheet handy and check all the levels so that I get as close as possible to 0dBFS at power amp input sensitivity at the level of preamp gain I prefer

If you attenuate between 9.5dB and 14dB on the Vivaldi with the 0.6V output setting going direct, running 0.2V into the preamp won't need its 12dB gain at all.

Using your preamp you first attenuate the signal from the source and then amplify it back to the level required for your listening anyway, since you're forced to apply the preamp gain to the signal no matter what. (the gain stage in your ARC preamp is fixed not variable like in Ayre's preamps btw)

If you have a TT you need a preamp anyway and it's irrelevant to the discussion what output setting you prefer on the Vivaldi through the preamp for various reasons; the discussion is about differences between DAC direct vs preamp and I think the Vivaldi direct should be used in its optimal configuration to the amps in question, for the result to be as meaningful as possible.

My take is that if you wouldn't prefer the Vivaldi direct on its 0.2V output setting to the preamp route, you don't really like how the DAC sounds and prefer the coloration/enhancement that the preamp gives you.