Pros: power, sound quality, and features.
Cons: Clipping at high gain, size, and a bit rough
Can I buy it?:
No. If you could, I wouldn't post a review on it from a product that I was involved in. This is for the people in the group that did buy them to see how it is from my point of view.
The build of the P-H for $150 is extremely good. But if we were to analyze it without care for cost, then it does have a few flaws. The top panel will exhibit some cave in if force is put on it. Also there is some loosening of the DAC line out on the back. Heavy bass songs will cause crackles as the bass rattles the connection loose. The frontal knob when pushed hard up and down does exhibit a few mm of freeplay but does not come loose. Otherwise, it is quite good. And if we consider the price of the unit, and the size of it, it is good for the price.
The buttons on front are very fun to push. It is always a joy to press them. There is no slow delay before unit change happens or LED lightup as some Chinese products will have which is very nice. The lettering is also nice to look at if you ignore the mistakes the contractor made.
The P-H has some problems with usability. The stoppers on the bottom do not fully actualy resist the unit on many surfaces that aren't already fricticious. This means that when inserting the quarter inch jack, you would need to hold the unit still to insert the jack. This is a problem exhibited on many units including my Audio-Gd but none the less, not fully being stable is still a black eye. Output to DAC line out when nothing is connected exhibits line out level noise by design. This was routed to DAC line out so headphone out doesn't have it but if someone has speakers attached, when they turn off their computers, it will play until they turn the unit off.
The only thing else with usability is operational usability. It is a bit confusing and there are some bugs as to when it will remember settings, and auto force I/O. It is confusing at first.
Otherwise, the unit works fluently. Plug the USB and power in, and press the power buttons and turn the volume. Easy as 1-2-3.
Sound Quality Introduction:
P-H uses a Burr Brown OPA2228 equipped Objective 2 Amplifier with dual NJM 4556 output buffers. It's DAC is a Cirrus Logic Flagship, the CS4398. It is commanded by a custom B1O command board. Let's take a look.
Project-H has a warm sound. It delivers slightly less sound-stage than say something like an Audio-Gd (and their discrete's). However, the soundstage while being reduced a bit is made up for with much more powerful presense of audio. I would say that P-H is a good amp. Honestly, what do people even think neutral can mean? The Audio-Gd is much more flat in terms that it doesn't accentuate as much as P-H does. P-H has a tendacy to really bring out the vocals and the bass which I find fantastic. But both have no sonic problems, so what can truly be neutral? The more active and natural sounding amp or the one that is more analytical by not accentuating anything? Well we aren't here to ask questions. The P-H itself also has a slightly accentuated bass response. This caused some problems with the Q701's but none on any other headphones.
To sum up the sonic qualities of the P-H, I would say that it is an active, fun, and natural sounding amp. It accentuates the mids and lows which makes things extremely pleasant to listen to. There are many amps that are fun in this price range of course, but few offer the level of detail and quality that can be heard from P-H. This is a full size source.