[Somnambulist]

Well there was a mention of a IEM-centric amp coming out eventually. I imagine that it would probably be a little more pleasing dimension-wise to most, although having used the uHA it's not really that big. Macro shots of gear on Head-Fi always make stuff look nice but a little larger than it really is!

 

[estreeter]

Quote:

Well there was a mention of a IEM-centric amp coming out eventually. I imagine that it would probably be a little more pleasing dimension-wise to most, although having used the uHA it's not really that big. Macro shots of gear on Head-Fi always make stuff look nice but a little larger than it really is!

Said 'mention' came from a Head-Fier - my read of Justin's response was that he wasnt willing to commit to the production of said 'IEM-centric' amp : always happy to hear otherwise.
 

 

[Somnambulist]

I think that was someone who went to the UK meet and actually talked to Justin, his reply to someone's online enquiry was "we won't talk about stuff till it's available".  I think.

 

[Mute-on]

Hi All,
 
First post after a while viewing.  This has been prompted by my recent purchase of a uha-120 with the Vishay volume pot.
 
I actually had Justin perform the high/low gain mod on my sample.  A genuinely nice guy who is obviously more than enthusiastic about both his own products and headphone audio in general.
 
Even at the low gain setting (6dB.  High is 12dB!) it drives my Beyer DT 250 80ohm with ease.  Comfortable low level listening at no more than 9 o'clock.  The reason Justin suggested this setting was to use with the output of my M2Tech Young DAC, which I just tried.
 
Playing Red Book through Macbook Pro > M2Tech > uha-120 > AT AD900 the sound through the uha at no more than 9.30 on the dial  was AMAZING!!!
 
Totally balanced, tight deep bass (yes on the AD900), solid attack, full midrange, shimmering treble (no sibilance), excellent depth and soundstage.  Honestly, though I have no other amps to compare the uha to, I can't imagine a significantly better presentation to my ears, at least in so far as you get the overwhelming impression that what you are hearing is simply what's on the original recording.  Nothing is exaggerated and nothing is left wanting.
 
Clearly the source has a lot to do with the final sound, and all I can say is any deficiency is more likely a result of poor source than Justin's little uha-120.  It compares more than favourably with my Naim pre-power and 2.1 stereo (10" sub and studio monitors).  I've also tried it fed by iPod Touch alone, and iPod Touch > Pure i20 (internal DAC) > DT250/AD900. In all cases, Justin's amp showed up the limitations of the source and clearly improved on the unamplified arrangement.  
 
In short a transparent, balanced and highly musical amp.  Now all I need is a pair of LCD-2 or HE-500 to justify owning it ... 
 
Just my 2c, anyway.
 
 
 
 

 

[estreeter]

I agree that the amp works well with the AD900, but I hope you were joking about the HE-500. Big difference between being able to get reasonable volume levels out of something like that and being able to drive them with authority - just my 2 cents worth. LCD-2 would be closer to the mark, but I'd still prefer a desktop amp for any of those cans.

 

[RobinHiFi]

We received a new batch of the Revision B uHA-120 amps at HiFi headphones earlier this month. Justin has tweaked the design slightly to allow the end user select one of two maximum gain presets along with providing a tool kit needed to disassemble and select the desired maximum gain. He has made some other slight refinements to make it easier to open the amp (assuming that you know how to use a hex key). Full details of the changes along with a handy jumper setting guide are on the uHA-120 product features page - http://www.justaudio.co.uk/uha-120.html. He has also created an online sound pressure level estimator, which he hopes will be useful, since it should help to provide some estimate of perceived loudness for different headphones/IEMs - http://www.justaudio.co.uk/tools.html.

Due to lack of availability of the customised Vishay  P11 volume pot (remaining parts reserved for AHA-120), we are stocking the standard professional audio pot version. What is surprising however is how good these are in terms of the feel, channel balance and low level adjustment. Justin has told us that he is quite amazed how good these are and he grades these himself to guarantee better than 1dB channel balance for custom orders in place of P11 (P11 throw is really too short for IEMs).

Anyway Justin asked us to check over one of Revision B amps, to (a) see how we found the process of changing the maximum gain preset and (b) also check the sound quality and confirm that we were happy that there was no perceivable variation in sound quality over the Revision A version.

All care should be taken not to damage the main board or any components, I found taking the unit apart nice and easy, the instructions felt clear and the demo photos really do help. I was a bit worried when removing the battery connection but again this was no problem and once done the board slid out easily. The jumpers are small and care is required but it is not Rocket Surgery, everything goes back together nice and easy and you are all done!

A little bit of experimenting shows the volume is the only noticeable effect, and it is immediately noticeable. A clever little addition which helps this great little amp make even more sense to IEM owners as well as Full size headphone owners or, since it is so easily reversible, fans of both!

 
 

 

[estreeter]

Thanks for the update, Robin.

 

[zer0hero]

Hey there everyone.
I'm contemplating between purchasing an iBasso D12 and this little amp here.
Could anyone provide a comparison between the two amps?
 
Thanks and Much Appreciated.
Zer0

 

[cn11]

There simply aren't many owners of the uHA at this point..
 
If you were looking for comparisons with the Arrow, I could help you with that, but that's about it unfortunately...

 

[ungucpho]

amp looks nice and compact

 

[estreeter]

Quote:

Hey there everyone.
I'm contemplating between purchasing an iBasso D12 and this little amp here.
Could anyone provide a comparison between the two amps?
 
Thanks and Much Appreciated.
Zer0

I cant provide a comparison, but I believe it would be an excellent combination : use the D12 as DAC into the uHA-120. Justin's amp will flatter most sources, in my experience, and when HiFlight confirmed that the D12/P4 combination (the P4 is another brilliant portable amp worthy of your consideration )  was very good I immediately wanted to plug a D12 into the uHA-120. Like everything in audio, budget is always an issue and I am not currently prepared to throw money at a luxury item. Will let you know if that changes 
 
(fwir, the one thing the D12 lacks is raw power - I believe the D4 was more powerful - and both the aforementioned amps have sheds of power)
 

 

[cn11]

Today I was using Headstage's DAC cable to my uHA from the work Mac.... just awesome sounding. 

 

[Anaxilus]

Quote:

Today I was using Headstage's DAC cable to my uHA from the work Mac.... just awesome sounding. 

Ahhh, so you like the DAC cable more than the UHA4 DAC it seems.

 

[cn11]

Unfortunately I haven't heard the UHA4... but it does sound like a pretty solid amp/DAC option. But as it so happens I was just perusing that comparison thread on the UHA4 vs. Arrow... 

 

[estreeter]

The DAC in the uHA-4 is pedestrian - it does the job but its the weak side of the equation compared to the amp section.