AlexS wrote: is it possible for a layman like me to diagnose/test my setup on whether or not I'm having that impedance difference problem?
I'm not sure of a way of quantitatively diagnosing this without an oscilloscope. If you have one, you could send a sine signal via your sound card to your headphone jack/amp (e.g., you can do that in Audacity with the tone generation utility), and measure its amplitude by connecting the oscilloscope across your headphone jack/amp. Then, look at how the amplitude of the signal varies with frequency of the sine wave. If the amplitude varies by orders of magnitude as you sweep the frequency between ~ 50 Hz and ~ 20 kHz, chances are the source signal's being filtered somewhere.
Though as I mentioned in the above post, I just ended up getting a cheap TDA1308 amp (which has an output impedance of 0.25 ohms) to power my headphones, to test if filtering was occurring in my laptop headphone jack -> headphone setup, and could easily hear the difference. The mids dropped, and the bass and highs rose, making the sound seem much less muddy.
AlexS wrote: I'm currently struggling to find some way to make PTQ sound the way I would like, and also sometimes have impression that sound sort of "muddy".
I'd second what NormB said here about trying a variety of different headphones (being sure you're not using an amp that results in a filtering of the signal, and maybe also using it with an external DAC), and only then changing PTQ presets/parameters. For what it's worth, I currently use a pair of Sennheiser 558 HD's with the TDA1308, and am generally pretty happy with their PTQ performance.
skip wrote: I did some testing of one of my laptops once, and found that when I selected the Headphone output, the output impedance was much lower than it was when I selected the Line Out.
Interesting - how'd you measure the output impedance of that laptop port (that might also answer AlexS's other question)? I guess the relatively high output impedance of the line out is consistent with it providing a relatively low current (and hence power) compared to a headphone amp.
Last edited by Andrew Spargo (17-06-2016 15:43)