I understand the need for audiophool blabber with headphones to a certain degree, as the interaction between a headphone and a human ear is very complex and difficult to measure, different measurement fixtures will produce different results, even moving the same headphone that's being measured on a fixture just a few millimeters can significantly change the measured frequency response, especially in upper treble regions. Therefore, if someone needs to know how a headphone sounds and they cannot try the headphone themselves, a combination of well-made measurements and a verbal review by someone with good ears and experience with audio is needed.
But DACs and amps are a different thing - they simply either convert a digital signal to analog or amplify an analog signal. Those devices only serve to feed a speaker or a headphone with a signal, the signal ideally being as close to the recorded signalas possible. Two DACs that measure close to each other enough (in terms of SINAD, FR, channel crosstalk) and use similar digital filters, cannot be different in terms of soundstage, (micro/macro) dynamics/detail, "analyticality" of the sound etc. If the reviewer compares two such DACs and mentions one of them having better details or a warmer sound, for example, it is most likely because they are imagining things based on what they know about the product (example: DAC A is made by comany X so it should sound better than DAC B made by company Y) or they have not properly matched the volume between the two DACs (ideally using a level meter or a similar precise method). You would be surprised how much of a difference increasing the volume by just 1 dB does to perceived "dynamics, clarity, details" etc, instead of being heard as a difference in volume, which is the only thing it really is.
In conclusion, human hearing is a very subjective thing, closely connected to our thoughts and emotions, and it is very easy to fool our brain into thinking we hear things that are not really there. I do not care how much experience someone has or if they have "golden ears". Hard data and measurements will always be more precise and valuable than anyone's subjective listening impressions. Take for example bluetooth audio and LDAC vs SBC. People will keep claiming how great LDAC sounds and how bad SBC is, while in reality, they are very likely listening to LDAC at 330 Kbps, which is measured to be worse than SBC (most headphones support SBC's High Quality profile with which the noise/distortion is below human audibility threshold). (sources
1 2 3)
This is not meant to be directed against VSG, their review of the Topping DACs/amps or anyone in particular, just my general opinion on audio equipment reviews
