help me to understand the gain

Less power output won't solve your issue - gain is separate from power. According to Stereophile, the DNA-1 has a gain of 32dB! That's really high, and a big part of your problem. I would investigate either a passive preamp or, if you like the Primaluna, talk to Steve McCormack (http://smcaudio.com/) and see if he can cut down the gain on your DNA-1.

The problem will definitely get worse with the Zus. I own Druids, and had to take some gain out of my power amp to make the system work.

David

You don't change the gain of the amp. You change the gain of the preamp. It is easily done with a resistor change.

The McCormack DNA-1 does have a pretty high gain but still a sweet sound. Even its little brother the DNA.5 Deluxe that is really musical has a gain of 29dB.

At one time I had a McCormack DNA-1 Deluxe, with a McCormack TLC-1 Deluxe preamp with signals being fed to it from a McCormack DAC-1 and an Oppo BDP 83 as a transport. Speakers were a rebuilt pair of KEF 104/2s that have a 92 dB efficiency. The room they were in was on the small side and the sound would get really loud with volume a little past the 9 o'clock position. The soundstage was great and the sound was crisp though.

I agree with some of the posts on top. You may have to modify or change your preamp to one that has lesser gain or your source to one that has a lesser gain or warmer sound. I say keep the DNA-1 but I have a heavy bias toward McCormack gear.

Couldn't find the Vout spec (or any others) on the Maverick DAC. If it's over 2V, that could be the problem. On a Monarchy DAC, it had an internal dip switch for 3V/6V output. High output is typical for DAC/preamps with a volume control.