From what I understand of the methodology:

- This was a DBT between a Schiit Magni 3+ and Schiit Magni Heresy amp. According to

Schiit's webpage both amps look the same apart from paint finish, sell for the same price. Looking at the specs, the obvious differences between the two include IMD (<-103dB vs. <-112dB at 1V, 300 Ohms respectively), SNR (>110dB vs. >115dB at 2V), Output impedance (<0.2 Ohms vs. <0.33 Ohms), input impedance (25k Ohms vs. 50k Ohms), and topology (one has fully discrete components, the other has op-amps with no overall feedback).

- He level matched all the headphone amps at the output using a DMM (Digital Multimeter) to 0.01V RMS.

- His kids did the swapping for him while he was in another room, and he used the same headphones.

- There were no measurements of any kind apart from level matching with said DMM, perhaps he does not own an appropriate setup. However, the manufacturer does post results of both amps using an Audio Precision APX555 here for the

Magni 3+ and for the

Magni Heretic.

- I might have missed it somewhere, but he does not mention which headphone he was using.

Result: 100% correct out of 10 attempts. The likelihood of guessing 10 correct answers with a choice of 2 is 1/2^10, or 1/1024. If this is true, then in my opinion this is a valid result.

Feasibility: is it possible for two amps by the same manufacturer with different circuit topologies, different input and output impedances, and different measurements to sound different, such that a trained ear can reliably pick them with 100% accuracy in a DBT? I would think so.

Opinion: IMO his methodology was sound. I would like to have seen more test subjects and some measurements (to verify the manufacturer's own posted measurements), along with presence of unbiased observers, but I can understand the limitations of hobbyists conducting experiments at home so I do not necessarily mark him down for this one. I have ignored all the anti-ASR snark just as I ignore all the snark on ASR. For me this is a valid DBT result and I warmly congratulate purr1n for making the attempt.