Most Neutral Desktop Amp (Preferably cheap)

The O2 appears neutral, but you'll need to DIY it.

Otherwise, I'd look at the new $300 Dynalo or a used Gilmore Lite.

If you're going to DIY, The Wire has even better specs and should be more neutral (may or may not be audibly so).  There's also the issue of rigging up a volume control if you're interested in that, and you may need better gear to do the few surface-mount components.  It also costs more.

O2 is available from JDS Labs (of CMoy BB fame) web store, assembled, for $95 with batteries but no AC adapter or enclosure.  This is competitive in price with like FiiO E9, all things considered, so I don't think you were expecting much cheaper?  It can work on AC or on batteries.  Take out the batteries and pretend they never existed, if you want.  Note however that the current version has kind of awkward placement of the on/off switch, jacks, gain switch, volume control--they're all on the front side, though spaced reasonably.

http://www.jdslabs.com/storeAmps.php

It says that the AC adapter is not included.  The cheapest AC adapter that works (120V mains power) is this WAU12-200:

http://www.mouser.com/ProductDetail/Triad-Magnetics/WAU12-200/?qs=sGAEpiMZZMtpkqKkT5w3un3pkjTLcmETCiy%252bdMCoShs%3d

If your AC line voltage is low or you intend to drive very insensitive, lower-impedance headphones (think like HiFiMAN planar magnetics), use the stronger WAU16-400 instead:

http://www.mouser.com/ProductDetail/Triad-Magnetics/WAU16-400/?qs=sGAEpiMZZMtpkqKkT5w3uqDKK8oOgNqoNREaAcZppQ4%3d

In general, the WAU12-200 is not a problem for listening to music, and there is no degradation in sound quality using it.  The builds fit into a Box Enclosures B2-080 (available in several colors) box, but you still need to figure out a front panel if you want one.  You may want to order the AC adapter and enclosure from the same place to save on shipping.

I've heard you can get a B22 built for under $300 - 400 if you do it yourself with cheap components.

Quote:

Originally Posted by Sonic Atrocity 

The 02 option sounds kind of interesting. Is an enclosure and front panel necessary? And is it actually neutral? Also, would I be able to run this from a Clip+ (Rockboxed) sitting at my desk? Right now it is my "dac" until I establish better finances. I really want a flat FR hence I have the Clip+ (Rockboxed) and will be purchasing the Fischer Audio 003.

Enclosure and front panel are unnecessary, though there may be a little more noise without what amounts to a ground plane running underneath the PCB (the metal of the default enclosure would act as one).  It probably goes without saying, but don't touch contacts on the bottom of the PCB or allow them to rest on any type of conductive surface, for fear of shorting them out.

Follow the link on JDS Labs or search O2 (short for Objective2).  There are links to many measurements of the device.  It has very high fidelity, so what goes in is what goes out (with very few additives), regardless of what you're loading it with and at what reasonable output level.  That would be my definition of "neutral" but some may have others.  The designer is a member that's banned from head-fi, so direct links are not allowed.

I built one and was unable to detect any noise from it.  I ran it through RMAA and loaded it with 32 ohms @ 1.1V, but the performance was limited by my sound card and not by the amp.

Max output is about 7V rms into 80 ohms or more, 2.25V into 15 ohms.  FR is flat:  -0.04 dB at 20 Hz and -0.01 dB at 48 kHz and flat between those frequencies.  Noise is about -115 dBV, typical THD+N is about 0.002% into 15 ohms but usually less than 0.001% into 80 ohms or higher, typical IMD below 0.001%.  Check the rest at the source.

You can run this from the Clip+ with no problem.  There's actually a Clip+ review at "that" place as well.  The max output of the device is just a bit under 500 mV.  O2 default gains are 2.5X and 6.5X to bring that to 1.25V or 3.25V, so you couldn't actually use all 7V it is capable of...then again, most headphones don't need more than 3.25V anyway.