I finally got around to comparing the A90 D and my schiit freya s. This was as pre amp only, not HP amp though. Listening was not blind, but observations were kept private until end. I level matched(72 db) using a chesky test tone and cell phone app. then used a cd quality chesky recording, node 2i to modius e to pre amps to ATI 542 ncore to ls50.. All balanced. I told my son to listen to tonality of instruments and "image", which I purposely didnt define.
My 21 year old son and I listened to same 30 seconds of music 12 times on the a90d in high gain. It took about 30 seconds to switch cords. Then 12 times on schiit freya s in its active mode. I told him to write down, in short phrases, how the two compared.
we both noted: more bass for a90D, slightly hot treble for Freya, cellos sounded more prominent on a90d, violins on schiit(elevated highs?). schiit wider, bigger image
contradictions: subjectively we preferred different pre amps, I distinctly noticed a smaller more forward image on the a 90d and better and better bass extension. I thought the schiit's image depth was subjectively better, but more diffuse.......my son said he did not really understand my lingo or agree with what i heard. he thought they both sounded good, and not real different in the end. I will not impart that whole vernacular on him. This part belongs in psychoacoustics probably, but Noam Chomsky and others have shown that the vocabulary(and understanding of it) we have can influence/limit our cognition in those areas. I sometimes worry I'm hopelessly biased by 30 years of audio reading. i dont want to pass that on.
On tuesday i will cover rack, so it is blind for my son. Same process, but only 6 plays each. by memory and his own written description i will see if he can tell them apart.
I'm pretty sure i wouldn't sell either. I've had no operational problems with a90D, but have not even listened to the headphone amps..........
