DVC - Drastic tone changes?

[Barib]

So, I'm an audio enthusiast/musician with a few different headphones, DACs and amps. Poweramp is my main music app. 

But I've always been conflicted with DVC; whether I want to enable or disable it. 

It seems to have VERY different effects, based on my amps or headphones. For example, my 1000Xm3's sound more bassy and bloated with DVC on. I have to EQ the bass much lower. 

However, with a full headphone amp and DT 1990's, it sounds very 'shallow' and bright with DVC on. There's no body or bass, but detailed treble. With DVC off, it sounds fuller/more punchy, but also quite muddy. It's a drastic difference. 

With an underpowered amp/dac, it sounds best with DVC on. It's full and warm, with good treble. Now, there shouldn't be such a big difference. Through my PC with WinAmp, both these amps sound identical (as they should). 

I'm just so confused. DVC has the opposite effect with different headphones. Is it something about controlling the DAC directly? 

[maxmp]

@Barib DVC controls volume in the way you have enough dynamic range for tone/equalizer frequency amplification. It doesn’t in any way process or modify audio signal.

As you have enough dynamic range, your basses may go way higher without overloading output/hitting limiter.