I have a pretty noobish question:
If I hook up two headphones at the same time, does a multiple input amp like the E9 (or even the E7) work harder to power the headphones? I ask because I actually have my DT990s on my 6.35mm jack, and my desktop speakers (with it's own volume control, so I keep the volume regulated) on the 3.5mm input. I don't use my desktop speakers often, and 90% of the time are off, but I was wondering if this is stressing the E9 more when driving something like my 600ohm DT990s than if I had the speakers or another headphone unplugged...
Another example is:
The K701 and DT990/600 are close in volume level despite very different ohm ratings, and was wondering if it's okay to have them both plugged in and gain the same benefit as if I only used one at a time. Just curious. I'm completely new to understanding how an amp's internals work and my first assumption iwas that the 990/600 is getting less juice to drive them when I plug in something else in that is also being driven...