Divo,
If you're running into a high gain phono stage (no transformers) then IME 100 ohms is ABOUT right. Every system is unique however. In one (slightly bright) system an Airy 3 wanted something a bit lower than that. I haven't heard one in any system where 300 ohms was right, though YMMV of course.
In any system, be prepared for changes during the break-in period. If you've read my review you'll remember that our Airy 3 needed 6 or 8 progressively lower impedance settings during the first 100 hours. Don't be surprised if what sounds well-balanced today becomes too bright tomorrow. Our Airy 3 did that repeatedly. Be patient, it's worth it, but don't expect any adjustment to hold until you have at least 100 hours on the cartridge.
The sign of full break-in is a sudden and startling integration and extension of soundstaging, imaging and air plus a reduction of grain in the upper mids and treble. When those things happen the cartridge's impedance needs should remain stable and the adjustments Thom suggested should hold for longer than a few hours or days.
Enjoy the ride!
If you're running into a high gain phono stage (no transformers) then IME 100 ohms is ABOUT right. Every system is unique however. In one (slightly bright) system an Airy 3 wanted something a bit lower than that. I haven't heard one in any system where 300 ohms was right, though YMMV of course.
In any system, be prepared for changes during the break-in period. If you've read my review you'll remember that our Airy 3 needed 6 or 8 progressively lower impedance settings during the first 100 hours. Don't be surprised if what sounds well-balanced today becomes too bright tomorrow. Our Airy 3 did that repeatedly. Be patient, it's worth it, but don't expect any adjustment to hold until you have at least 100 hours on the cartridge.
The sign of full break-in is a sudden and startling integration and extension of soundstaging, imaging and air plus a reduction of grain in the upper mids and treble. When those things happen the cartridge's impedance needs should remain stable and the adjustments Thom suggested should hold for longer than a few hours or days.
Enjoy the ride!