Its my guess, its good to stay away from driving Z's 1 to 3 times the nominal headphone Z. Lower and you get constant voltage, and much higher you get constant current feed. This I am thinking will minimize impedance responce errors.
greg
OK - wasn't even half concentrating.
d-- Pearce Consulting http://www.pearce.uk.com
I have the impression that headphones are designed to work in range from no higher than matched impedance to constant voltage. Hi-Z phones tending more towards constant voltage, and Lo-Z phones more like matched impedance.
In the case of HD-580s, I am comfortable with source impdances from about 80 ohms to 16 ohms to minimum.
There is a lot of variation among the Z plots from that web page. i'll have to study them some more.
greg
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