Originally Posted By: Matt Finley
A line out signal is a specific voltage and impedance standard. The headphone out can be set with the right gain to approximate the correct line out level if you get lucky, but the impedance is still 'off' by a bit.

Unfortunately, some consumer equipment will muddy the waters by labelling one output as both.


I'm not used to seeing stereo Line Outs — yikes!

Headphone Outs are not Line level but doesn't mean you can't use them in a pinch—or at least try.

Another thing that's confusing is that interfaces can have inputs labelled Line In and clueless Marketing departments will state that you can hook up your keyboards etc. when Engineering designed them as Line level inputs. MOTU did that with the M4—when we hooked up our keys, they could barely be heard. MOTU fixed the ads and documentation eventually.

Most keyboards need Instrument level inputs, BTW. The TRS center jack on most interface CombiJacks is where they plug in.


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