Headphone Heights

Sure, headphone output jacks can be used as a "preamp out"...

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This Post Has Been Edited by the Author

In Reply to: RE: Can headphone-out be routed to RCA Jacks in-Amp? posted by Rapalyea on December 20, 2013 at 09:16:58

All you would need in most cases is a simple (1/8" or 1/4" plug to dual RCA) adapter cable.
However, headphone amps will often have a much higher output impedance rating than dedicated preamps do. It is almost always better when the output impedance rating of your "preamp" is very much lower than the input impedance rating of your power amp (a ratio of 10 to 1 or higher would be good). If this ratio of output impedance to input impedance is too low, dynamics and/or flat frequency response can become compromised.
So, unless the input impedance rating of your power amp is unusually high, the sound quality you will get from a typical headphone amp (used as a "preamp") will probably not be as good as the sound quality you will get from a decent dedicated preamp with it's much lower output impedance rating.
That said, I do have a pair of ASL Wave 8 tube monoblocks that have unusually high 100 K ohm input impedance ratings. And they do sound surprisingly good when driven by my DNA Sonett tube headphone amp (again, with it's high-ish output impedance rating) - partly because the aforementioned ratio of output to input impedance is acceptably high. Just remember that many (or most) power amps do not have such a high input impedance rating...
But, the basic answer is "YES". A headphone amp can most certainly be used as a makeshift "preamp", in a pinch.

Edits: 12/21/13

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