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- Jan 24, 2012
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From level matched listening tests using the HE-560 driven by the O2+ODAC and higher wattage Hifiman EF5, I'm not getting any distortion from the O2. If anything, the EF5, being a tube hybrid, subtly smears the detail more due to the tube input stage. This is on tracks that I know well and what details to listen for.
I was impressed with the detail level on the EF5 already, but the O2 is just cleaner. The gain on the O2 should be matched with the input voltage, of course, and the EF5 has more headroom on the volume knob.
Since you mention it, I also switch between to a STAX electrostat from time to time, and as far as this 'inaudible distortions that smears the micro details' are concerned, it really seems you like to cherry pick your arguments, providing technically plausible but one-sided explanations that have no basis in actual usage an experience.
I'd personally put much more weight on extended listening experiences of people who actually have the equipment on hand, over your soap box musings.
Where did you get that the Hifiman EF5 is higher wattage?
It uses an OPA275 op amp for its output stage, as far as I know... (unless Hifiman doesn't know their specifications well), the datasheet recommends that the OPA275 be current-limited to 30mA (peak to peak) swing. Even when the designer decides not to do that limitation, the op-amp itself has an internal 30-Ohm resistor that limits its current swing to +40mA and -90mA, so if anything that's actually worse current specs than the O2's theoretical +200mA and -200mA.
Here is the datasheet in question:
http://www.analog.com/static/imported-files/data_sheets/OP275.pdf
So in fact, you just supported my argument that when you have less headroom, distortion would smear details way before the brick wall is reached.
But please feel free to correct me if you find anything else.