@Yohn,
I understand that impedance mistmatches are an issue. But one can't use that argument always as is done very often with jitter in DACs to justify anything.
This is a very good (professional)DAC with its own volume control:
Now with the GoldPoint, or maybe whatever stepped attenuator:
Noise floor with the external attenuator is lower. So, using normal cable lengths as most of the hobbists here do, what's the benefit of passive mode in the Pre90, the Shiits or whetever, over a humble stepped attenuator?. Looking at this graphs I get the impression that those pre-amps look like over-engineered for something ordinary resistences can do.
I'm sure I'm missing something, but I'm struggling to understand what. Of course, I'm always speaking of passive attenuation.