Yea thats why I want to keep the RME ADI 2 DAC FS, so I can tweak EQ a little to bring me whatever I need.
About to receive Burson Soloist 3XP next week. Cant wait! Should be some serious sound upgrade. HP: LCDX 2021.
I am pretty sure it will be an improvement, but speaking from personal experience, do not put your hopes too high. I had the exact same gear as you. The ADI-2 drives the LCD-X pretty well to be honest. You can add some mild EQ and so on.
Adding the 3XP to the chain with single ended output did not turn the world upside down for me. Yes, balanced mode was more improvement and then using the 3XP in headphone power amp mode another step. (Make sure, you do not use the low impedance LCD-X in high-gain, as you will hear some hiss. Medium gain is alright.)
What I am saying from my own experience, is that the ADI-2/3XP combo with the LCD-X versus the ADI-2 alone was not as big of a revelation to me as the ADI-2/3XP combo can be with some truly high-end headphones like the Empyrean for example.
While I definitely heard some improvements with the LCD-X (and a little more improvements with the Arya), the combo basically transformed my Empyrean versus ADI-2 alone.
There is always a limiting factor in anyone's chain. To my personal experience the limiting factor in the ADI-2/3XP/LCD-X combo is the headphones. Which is a rare case, as usually that is the link in the chain that lasts the longest. Saying this as someone who really likes the LCD-X.
I just want to save you from potential disappointment due to high hopes. This was my experience, your experience might differ.
Either way, please make sure you share your thoughts once your 3XP arrives.
Also, don't judge the amp too soon. Give it the deserved burn-in time and your ears to adjust to the sound and appreciate its delicacies.