Many thanks for your explanation! I'm starting to understand this better.
My main DAC is the the Holo Audio Spring 3 KTE (5.8Vrms XLR) and I've also got a Gustard X26 Pro (5Vrms).
I have two preamps, the Holo Audio Serene with +6dB gain, and the Topping A90 in preamp mode, also +6dB in medium...