This will be a long rant that comes a bit late given that Alpha Prime is (just about) extinct, but then I happen to discover them late and think the cans deserve (more, even if late) recognition. And is just my ears' opinion.
Before I start ranting, let me say the Prime need imho the best possible source/signal one can feed them so the'lly expose ability. One may argue that's the case for most cans, I think not. So I took all the steps I can think of to clear/improve the signal in my setup as much as possible. All added together, these steps are rather expensive (may rival the cost of whole setup) but I supplemented with diy, ingenuity and patience to reign tough on cost. And succeeded to a great degree.
My setup as I write this (if you're interested I'll provide all details & sources) consists of end-to-end: excellent power conditioner/filter (pro audio unit), superior (7 awg, flat wire, top name) power cables and connectors (can't believe the price on these suckers
) for both the DAC and the amp, top USB cables (needed 2 and combined one with pure silver and with 7 Ns OCC coper), active USB ground-noise filter and re-clocker, top XLR cables between DAC and amp, with ferritte cores spruced across all cabling. And should mentioned if I haven't as DACs are important, mine is Matrix X-Sabre; as good as anything under 2K imho.
So as I mentioned, got around to make me a pair of headphone cables, one with 28 awg double-wired per channel pure silver (99.9999, found it ridiculously cheap, all supply's gone though), the other cable using the best OCC copper IC cable available consisting of 2 pairs of solid and 2 of stranded 22 awg wires. Burnt in the cables for about 20 hours, then gave the Primes some good listen for about two days, balanced output only (already listened to them thru the unbalanced output for 3-4 days, though using the standard oem cable only, which in all fairness is lame).
Balanced Vs unbalanced in regards to the Prime - the difference in both power and sound is significant, in that it can be clearly and immediately recognized. The power from A28's balanced is way more than my ears can handle, and of course much more than the juice flowing from the standard. As I write this, I listen to Miles' Live-Evil in 24bit-96Khz resolution (HD Tracks), volume positioned at at 9 o'clock even, about as loud as I would listen to under normal circumstances. Volume at 10 o'clock nears my 'everyday' threshold; at this point for me to go thru an entire album would be only possible if I am closing the day with a drink (or few) in my hand
Volume above 10 becomes intolerable to my ears for more than a song or two. And depending on genre/recording level not even that long. Which makes me think that if the amp in its current configuration (meaning transformer & power regs) can drive the Primes with such authority, and I mean hard-handed authority, why it wouldn't be able to drive more power-hungry cans even if the volume goes all the way to say 3-5 o'clock and max? I don't consider cans like HE6, but just wonder how will it drive them, just curious given our discussion on the previous pages.
Sound-wise, from the balanced output the Primes are expanded across the board. Sound-stage, clarity and detail, bass as a whole, every aspect. I'd say, yes there is a notable improvement going from unbalanced to balanced, even though A28's unbalanced signal is great to begin with, not like most balanced amp where the unbalanced is just an afterthought. The most striking thing for me is their neutrality - Prime will be flat out boring with flat recording, and will blow your expectations, imagination, mind, when given quality production in quality wrapping. To me that defines neutrality, the ability to sound truly outstanding when given the opportunity, it is what for me sets Prime apart from most anything else under $1500. Few cans can play true to source yet turn in stunning performance when called upon. Source may not be exciting and when that is the case Prime won't make it exciting for you. If the expectation is otherwise, skip them and get 'colored' headphones, TH-0XX point in case, awesome! I found for myself ( credit goes to Prime, helped me here big deal) that I rather have 'kings' of neutral and apply EQ when needed. I think is worth mentioning here that I have notable experience with Senn headphones which are often regarded as neutral - well, to me they are detailed and some of them extremely so. but they cannot go across the spectrum of sound the way Primes do. And that's neutral to me, the ability to reproduce the sound as intended, whether it calls for deep, shaking, bass growl, well define mids or clear and natural highs.
To sum it, the improvement in the signal path I implemented (noted above), supplemented by playing high-res/HD audio (at lest 24-96K and more like 192K and DSD, which on its own can make as much difference as all else together) allowed me to get a very good feel of what the Primes are capable of when given a chance, and form a conclusive (for myself as least) opinion - for those of us that value uncolored, balanced sound across the spectrum with rich details, the Primes are indeed exceptionally good headphones. I am repeating myself with different words, regardless if one wants to hear his/her favorite music for what it actually is, I think the only sub-2K headphones that are better than the Primes may likely be LCD-3 and Ether. That's how much I'm impressed with 'em!
And oh yes, real good amp is needed too, it is where A28 stepped in and marvelously so....i'd say....
...I am continuing after some listening break....hmmm, the Primes are not everyone's cup - agian, very detailed and neutral, unlike any other headphones I've heard, and it seems many music fans don't really like that. I'll try to poke my finger into it - the so called 'exciting' headphones tend to have exagerated sub-bass, that 'makes' the music more 'full' and 'engaging', among other descriptions. And I would agree, and admit that in a way it does. It is also my observation that most people fall in that category, hmmm....then I must fall in a 'purist' type of bracket, so who cares what my opinion is, right? ....