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https://www.audiosciencereview.c ... ectstream-dac.9100/
Listening Tests
For subjective testing, I chose to use the recently reviewed and superb Monoprice Monolith THX 887 Balance Headphone Amplifier. This Monolity has vanishingly low distortion and hence is completely transparent to DACs being tested. For the alternative DAC, I used my everyday Topping DX3 Pro 's line out RCA to Monolith. I then used the XLR input to connected the DirectStream DAC. Once there, I played a 1 kHz tone and used my Audio Precision analyzer to match levels using PS Audio's volume control. PS Audio claims perfection there ("bit perfect") so I figured they can't complain about that. The final matching was 0.3 dB difference between the two.
For headphone I used DROP + MRSPEAKERS ETHER CX with its XLR connection to THX 887 amp.
I started the testing with my audiophile, audio-show, test tracks. You know, the very well recorded track with lucious detail and "black backgrounds." I immediately noticed lack of detail in PerfectWave DS DAC. It was as if someone just put a barrier between you and the source. Mind you, it was subtle but it was there. I repeated this a few times and while it was not always there with all music, I could spot it on some tracks.
Next I played some of my bass heaving tracks i use for headphone testing. Here, it was easy to notice that bass impact was softented. But also, highs were exaggerated due to higher distortion. Despite loss of high frequency hearing, I found that accentuation unpleasant. WIth tracks that had lisping issues with female vocals for example, the DS DAC made that a lot worse.
Conclusions
Many of you would have guessed that PerfectWave DirectStream DAC would not do well on the bench. That is of course true. The real issue in my opinion though is not the internal design of the DAC functionality. After all, there are other companies that use the same approach and achieve superb measured results. The problem here is simple: the output transformer. Transformers are just not linear to the levels we expect to have in a DAC (as opposed to say, in a tube amp).
The sonic effects are there in my semi-formal tests. Perhaps the older audiophiles including the designer Ted Smith, have lost so much high frequency hearing that the harmonic distortion this DAC adds makes up for some of that and they think they are hearing more. If that is the case, just buy a Jensen transformer and put it on the output of your DAC and you would get the same effect!
The fidelity loss here is apparent in both objective and subjective testing. There is nothing to hang your hat on hence the decapitated Pink Panther which leaves no room for such attire.
Needless to say, I cannot in any shape or form recommend the PerfectWave DirectStream DAC.
These companies need to hire trained listeners and perform a simple level matched test before spending so much money on engineering and producing subpar products. Our hobby deserves better. Much better. |
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发表于 2019-9-28 15:13
