I feel obliged to add my two cents, since I'm one of the advocates of the maxime «Say no to amps!» Actually there are enough HE1000 (V1, V2) users who drive their favorite headphone (probably in most cases) direct from the DAVE, and there may be even a few Hugo₂ owners who do the same (if they haven't been talked into using an amp). Logically my standard configuration today is the DAVE/HE1000 pairing, but before the DAVE area the Hugo₁ was at its place – to my full satisfaction, to say the least. Since I own a few high-quality headphone amps, I've tried them out of interest, but none came close to the sound of the direct connection in terms of impulsivity, clarity and control.
Show me an amp that sounds like a wire with gain! I haven't met one. So what causes most of the difference compared to the input signal is harmonic distortion, there's no question about it. You're using a popular argument for an amp: control. I suppose you're not familiar with amplifier electronics. The only sort of control an amp has over membrane movement is via an output impedance as low as possible to avoid an emphasis of the resonant frequency. That's valid primarily for dynamic headphones. Planar magnetic headphones with their almost flat impedance response don't bear that risk, at least not to the same degree. So when you want maximum membrane control in any case, your choice should be the Hugo₂ – direct! Its output impedance of just 0.025 Ω is probably unrivalled among all the headphone amps you've ever tried. It belongs to Rob's concept «shortest signal path for maximum accuracy and transparency».
To weissja36:
There's a reason for the large preference of the direct connection with Chord DAC/amps. It's simply the best variant if you value honesty and transparency over euphonic effets such as artificial warmth of phat bass. With its even higher output power than my then Hugo₁ the Hugo₂ will have even less power problems with the HE1000, and now that we're talking about the HE1000 SE, there's no question that it will be an appropriate match both sonically and in terms of power reserves. Right now I'm listening to the Hugo₂/HE1000 just out of interest, and there's not the least wish to change something on the sound characteristic.
Of course the TT₂ will be even better than the Hugo₂, but with the M Scaler in the mix the latter is an option that deserves to be taken seriously.
Addendum: I'm a medium- to rather high-level listener.