Bottomless bass and clarity all at the same time.  Planar headphones love this little amp as well.  

Nice review with good overview of what professional audio and full size gear has to
offer to the headphone experience! very valuable in addition to brining a great piece
of gear and special uses to our attention Vapman!  thank you!

I bet planars would be incredible on this. Dang it, I might have to get my hands on some again...

Great review man, i wish you wrote them like a week ago

I have a pair of these wonderful little amps, running my KEF LS50 speakers, as mono-blocks.
They are such a fantastic value.  Parasound makes great stuff.  Especially considering the price - I bought mine for around $250 each.

I have a Zamp (v3) paired with a Zdac (v2) for my computer desktop system. The Zdac feeds a Velodyne MiniVee sub, and the sub's output feeds the Zamp in bi-amped mode (crossover at 80 Hz), which powers a pair of B&W XT2 speakers. The Zdac provides the volume control (independently for pre-out and headphones), and a better headphone amp than what's in the Zamp. Everything turns on/off with one click of the power button on the front of the Zdac (the Zamp and MiniVee power down automatically after a period of no signal.)
 
All in all, a really sweet sounding system, I've been very pleased with it. I love Parasound gear.

How is the Parasound - Zamp v.2 as headphone amp compared to v.3?

Don't know about the Zamp v.2, but the Zamp V.1 runs really warm compared to the cool running V.3  Opamp rolling in the V.1 brings in great results.  Just install a 8 dip socket.

Just purchase one from eBay. I had couple vintage receivers that had the dynamic power, headroom and soundstage but lacked transparency. 
This thing is less than quarter of the price of my headphone amps. Definitely worth trying. 

I have got some different people asking me about inexpensive volume controls for this amp. I use a Gemini MM1 mini DJ mixer, but those who want their signal 100% unaffected should look into a passive preamp. Schiit makes one that I have never used, but it is cheap and gets good reviews.

When you say Mojo, do you mean the Chord Mojo? 
Are these as transparent and detailed as higher end desktop amps? 

Great review, love your style! Quite tempted (I can pick one up used on Taobao) - what's the soundstaging like? Compared to, say, the Cayin C5 (a potentially odd comparison, but since you and I both have a C5 it's a useful reference for me!) To what degree does the Zamp provide an 'almost like being there' experience?

@sling5s Yes, I do mean the Chord Mojo.
@misteral201103 soundstage and overall character is remarkably like the c5. Kind of like a turbo c5. The edge goes to C5 because the OPA opamps it uses are superior to the stock zamp opamps. If you rolled opamps could probably beat c5...

Parasound makes good stuff. Been looking at HE6's and this to power them. I'm also considering the new Emotiva a-100 BasX (Class A/B, torroidal transformer, etc.) Does this supply all the power to the headphone jack (jumper enabled) like the BasX does?

"Direct output option for low-efficiency planar headphones - This option allows you to route the main speaker outputs of the A-100 directly to the headphone jack to drive low-efficiency planar headphones properly - without special cables or adapters."