I would not expect there to be any adverse sonic effects from the higher impedance. In fact it may be somewhat beneficial, just as it is desirable to have the input impedance of a power amp be as high as possible relative to the output impedance of the preamp that drives it (everything else being equal).
You probably would have to set the volume control higher, perhaps by 10db or more. That can be calculated from the specified sensitivities and impedances. If you have specific models in mind I can do the calculation, assuming the specs are available.
BTW, the sensitivity of many of the Grado headphones is indicated at their site as 98db/1mV. I believe that is incorrect, and that they meant to say 98db/1mW (milliwatt, rather than millivolt).
Regards,
-- Al
You probably would have to set the volume control higher, perhaps by 10db or more. That can be calculated from the specified sensitivities and impedances. If you have specific models in mind I can do the calculation, assuming the specs are available.
BTW, the sensitivity of many of the Grado headphones is indicated at their site as 98db/1mV. I believe that is incorrect, and that they meant to say 98db/1mW (milliwatt, rather than millivolt).
Regards,
-- Al