Pros: Added the right amount of bass and warmth to my K702's
Cons: VERY picky amp, I have only been satisfied with this amp paired with the AKG K702's
I purchased this amp from Meg Tube Audio on eBay to drive my k702's. At the time i did not know much about it but thought i would take a risk. Thankfully the risk paid off.
the design of this amp is rather nice. It has an aluminum body coated either red or champagne paired with polished oak. I went for the champagne color and am quite pleased. Its not the most beautiful amp around but i would certainly put it up there. The build quality on the 'Headphone' is top notch. it has secure tube sockets, quality RCA mounts, rigid chassis and full point to point wiring. The only issue i had with it was that it arrived with a scratch on the top transformer housing. I contacted Meg Tube Audio about it and they were very responsive and are sending me a replacement housing. So +1 to them.
The sound of this amp is just what i was looking for with my K702's. This amp takes my K702's and gives them the warmth and bass that they are lacking. This, I find, makes my K702's noticeably more engaging than before. And for those who feel the K702's are lacking bass, this amp may be the solution. It does not turn them into a basshead's dream, but it does move them up from bass light to bass... hmmm whats the word... normal. And it adds a nice bit of bass impact, which helps with drawing me into the music. The best part is that it does this without loosing the detail, transparency and sound stage the k70X's are known for. If anything it does reduce the sound stage a tad and pushes the sound a bit more upfront, but not dramatically.
So, I highly recommend these for K70X's. The only reason i ranked the sound a 4/5
★'s was because I am unable to compare it to any other headphone amp. Regardless, if you are looking for some added warmth and bass to you K70X's or any other headphone, this amp will help you do that. I liked my K702 before, but now I adore them.
UPDATE: OK, after living with this amp for a long while and getting some more experience with some other amps I can safely say that this is a KILLER amp for the K702's. I find myself having a hard time listening to my K702's on any other amp. So I have updated the audio quality from 4 to 4.5 stars.
I have also found that that not many other headphones seem to work with this amp. Well... when i say not many i mean none. The HD650's were too smooth, the D1001's had its vocals eaten up and the DT770 Pro's became the basshead's ultimate wet dream.
So, for phones other than the K702 I would advise some caution. If you want some added warmth and beefed up mids and bass than this is great option.
UPDATE 2: I've done a little tube rolling and had the chance to try a few more cans with this amp.
Im currently using a pair of NOS Mullard CV4024 tubes based on Skylab's suggestion. from what i can hear they have improved the dynamics, clarity and transparency. Its not a HUGE difference, but its deffinately worth the money.
I have also been able to listen to Audio Technica ESW9's and M50's with the J Sound Lab. The ESW9's weren't bad but its certainly not the best combo. I have always found the ESW9's to be a little tubey in themselves (which is why i like them) so adding in more tube sound is a little overwhelming. Surprisingly though, the M50's were quite nice. I found that the J Sound Lab pushes the focus of the M50's to the lows and mids (primarily the lows) but not so much as to drown out the highs. The bass is just awesome. It is clean, punchy and it has an extension that i have never come across before. Its not the perfect match but it's good enough with certain genres that it makes me switch to my M50's for certain songs.
A THIRD UPDATE!?! 5/11/12: Ok. so after a good solid year away from the J Sound Lab/K702's and instead using a my meier concerto/HE-4 (a lovely combo) I decided to bring them back out. The results were rather interesting from my point of view... but i think... i prefer my j sound lab/k702 setup to my concerto/HE-4's. I may have missed out on a whole year of superior music. I listened to some songs that I had heard a million times on the concerto/HE-4's (particularly "Sail" by awolnation, "Bukowski" by modest mouse and "Nude" by radiohead) and felt tickled in the ear constantly. Far more dynamic and deep than anything I had been listening to the past year. silky smooth, huge separation and just a hell of a lot more fun.
UPDATE FOUR 8/19/12: Short update, but i just recently received my LDC-2's. While i cant reccomend the J Sound Lab with the LCD-2's but i can further comfirm how good this amp is with the K702's. I have been using the LCD-2's with my meier concerto and it is a better combo than my K702/J Sound Lab combo, BUT (a serious but) not by much. The LCD has better bass, better separation, better extension, better dynamics, sparklier (derp word) highs, and better imaging but the K702's with the j sound lab seem much more natural, smoother and have remarkably better vocals (so far the best i have heard). I have switched rigs many times for certain bands/albums just for the vocals.
SO, the LCD-2/concerto combo is better overall but the K702/J Sound Lab combo does best it in a few areas and in some significant areas.