and that's one huge reason why you have an atten first, then a buffer after that, optionally with gain. after the buffer, you are low-z again and life is good
you never want to run cables from the atten - for very long distances - unbuffered. the high output z is very bad and noise WILL get in.
linux-works ... what a coinkidink .... My query for this thread mostly arose as a result of building myriad headphone amps -- CMoy, Tangent/Pi Meta, etc. -- so perhaps you're best suited to pontificate*** your usual excreta

=== !!WARNING!! --
SUBJECTIVE AUDIO EVALUATION BELOW. SAVE THE UBIQUITOUS "AUDIOPHILE"-BASHING MELODRAMA FOR THOSE WHOSE SINGLE PREAMP VACUUM TUBE COSTS MORE THAN MY
WHOLE AUDIO SYSTEM !! ===
Setting my DAP's (
a cheap $100 Chinese "iPod") volume to about 1/2 level [it operates in the digital domain, via the DAC], I am "forced" to use the entire range of my DIY PiMeta headphone amp's rotary (analog) volume control -- the max setting (five o'clock) being just at maximum tolerable level. To confirm,
quantitatively, I level matched the headphone amps output voltage, with a DMM.
Qualitatively, I noted a distinct improvement in subjective audio quality -- i.e., when compared
against the same voltage level with the DAP volume higher** (100%) and the headphone-amp (rotary analog) lower.
Dunno where I got the idea to test this ... maybe years or even decade ago there was some mention of it in Audio Engineering magazine ... or was it now long-out-of print High Fidelity

Anyway, it's an easy test for ANYONE to perform ... and most of you (even the most unaudiophile of the bunch) probably have orders of magnitude more invested in common/household audio gear than yours truly
HINT: There's a reason I'm headphones only ... speakers are way too $$.
** The
DAP in question has both headphone out and line out jacks. The digital volume control operates both. Most recommendations I've read -- WRT using the line-out with an external amp -- suggest one max out the source (DAP) volume. But this is not what I find works best for subjective eval. of audio fidelity. YMMV.
*** "pontifi
cate" ? ... or is that defe
cate ??
