The high outout mode comes on at 50ohms. So whatever gets you to 50 or more ohms.With my 64ohm Brainwavz HM5 I typically listen at 15-25 out of 75. The HM5 is somewhat high impedance, but is pretty sensitive. With my 62ohm Q701, being slightly less sensitive I listen to them at 25-35 out of 75. For my listening habbits there is always plenty of power. Even with my lower impedance iem's that dont trigger the higher output I still never exceed 40 out of 75.
1/20/16 at 12:40pm