I use my Rossini with a passive preamp, perhaps the best on the market, a bespoke audio
Here is what @PaleRider had to say on the subject:
I don’t use an active preamp, but my experience has been similar. My system sounds better with the Vivaldi DAC running at 6V with a Townshend Allegri Reference Pre attenuating the volume, than it did with the DAC at either 2V or 6V and controlling the volume with the Vivaldi.
I am a big fan of autoformer passive attenuators and Dave Slagle makes some of the best,
he can make a balanced unit