Edit: SRH1540 vs Alpha Dogs
Jan 21, 2015 at 3:07 PM Thread Starter Post #1 of 10

saguro

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I'll try to keep this short and to the point.  
 
I'm looking into purchasing a headphone amp (Lambert Play it by Ear) and slowly upgrading the rest of my gear over the next year.  I currently have two sets of headphones I use: Shure SE425's for office, and Bose QC15's for when I travel.  
 
Output comes from Macbook Pro Retina, Iphone, and PC w/ soundcard at work.
 
Is my money wasted on the amp or will I notice a difference with the amp?  Should I be investing in better headphones prior to this?  I notice a significant improvement from my work PC to that of my iPhone already for instance (less roll off of lows).
 
I appreciate your opinions on the matter, and thanks!
 
Jan 21, 2015 at 9:48 PM Post #3 of 10
 
I'm looking into purchasing a headphone amp (Lambert Play it by Ear) and slowly upgrading the rest of my gear over the next year.  I currently have two sets of headphones I use: Shure SE425's for office, and Bose QC15's for when I travel.  
 
Output comes from Macbook Pro Retina, Iphone, and PC w/ soundcard at work.
 
Is my money wasted on the amp or will I notice a difference with the amp?  Should I be investing in better headphones prior to this?

 
OK, first off, there are a few problems with using a headphone amp. First is that the iPhone wouldn't be able to send out a line out signal as clean as the old 30-pin line outs without bulky adapters; it's more suited for digital audio out nowadays, but you still need the bulky adapters if you're not using a dedicated iDevice DAC-HPamp. Androids have the same problem, that's why my devices from Apple and Samsung are mostly used as desktop (at most transportable) systems when using a DAC-HPamp with them.
 
What you don't see in the photos are the bulky adapters, which was the whole point in getting the sync docks to begin with (aside from keeping them upright).



 
Second problem is that it's not a matter of "better" headphones but that your current headphones don't really need that much more power nor current, or can't use them at all. The SE425 is more likely to encounter channel imbalances with a more powerful headphone amp that uses an analog potentiometer (ie the volume control), and when using your Macbook and PC, the reason why you're not encountering this problem is because you are using the volume control on the OS. That doesn't have the problem with uneven tracking on an analog unit, but it has another problem: using it below 100% means you are reducing the bit depth of what you're listening to and hence the dynamic range. You could be listening with the dynamic range equivalent to 10bits for example (note that it doesn't mean the whole recording will sound like an NES midi soundtrack - it only affects dynamic range). At the same time the SE425 might even produce an audible hiss due to its high efficiency and this happens with amps that don't have a very quiet background (ie very, very low background noise), although this is more of a problem with the SE53x.
 
The Bose QC15 on the other hand has its own amplification circuit, since it has an active noise cancelling feature. That means what it receives technically is just as good as sending it a line out source. Sure, a headphone amp may have a higher voltage hence it will be effectively louder, but all the benefits that can be derived from having that amp driving the transducers directly - like better control, low output impedance, low THD, etc - won't matter anymore since in effect it will just be a line out signal going into the QC15's active circuit, which then still ends up as the primary amplifier driving the headphones.
 
 
 
I notice a significant improvement from my work PC to that of my iPhone already for instance (less roll off of lows).

 
Like I mentioned above, this isn't the ideal set-up either. It may not necessarily just be due to the more powerful circuits on the Mac and the desktop PC vs the iPhone, but for example simply the higher voltage (which, as explained above, can be achieved with an ampbut in the end invalidates its qualities as an actual amp on the QC15, while potentially causing some other issues on the SE425) or you might be hearing dynamic range compression if you are using the software volume control. In some cases DR compression doesn't sound like what its name sounds like, since you perceive some sounds - in this case the lows - to be louder, but there is a possibility that what is happening is you lose the relative dynamic range as recorded and you are hearing everything at an equal volume (which, as per DR compression, doesn't necessarily mean more hi-fi). There are actually tricks via software or even hardware DSP that deliberately does this to compensate for playback hardware shortcomings, or as deliberate sound shaping. Or it could all be a combination of DR compression as well as the higher voltage/output off the computer.
 
You could try something like the Ibasso D-Zero MkII, and use it on low gain with the SE425 for now. Don't expect much for driving the Bose with them though - even if you can go louder since it increases the voltage, ultimately the distortion levels, current, and damping factor on its own amp will be what determines how well the drivers are controlled - but that should be enough to upgrade to other headphones. Note though that a circumaural headpone may not necessarily be more efficient vs ambient noise compared to the Bose, which even if they have a more neutral response and less over distortion, can still be a problem is ambient noise is getting through, like at the office. What you can opt to do of course is use the Bose at work, and then maybe use another headphone at home.

Given that, it might be better to just save your money and focus on building a completely fixed desktop rig for your home - DAC, HPamp, headphone - than upgrading anything portable or for work.
 
Jan 23, 2015 at 12:37 PM Post #5 of 10
Thanks for all the helpful replies. I think the general consensus is upgrade gear and source first, then worry about a new DAC and amp. I guess I got caught on the amp hype after switching power amps on my stereo from an onkyo to a Bose 1801 and hearing the difference.

With regard to new cans, I'm currently really interested in the Hifiman HE-500 and the mr. Speakers alpha dog. Thoughts on one over the other? Especially if I use them occasionally with an iDevice?
 
Jan 23, 2015 at 12:44 PM Post #6 of 10
Thanks for all the helpful replies. I think the general consensus is upgrade gear and source first, then worry about a new DAC and amp. I guess I got caught on the amp hype after switching power amps on my stereo from an onkyo to a Bose 1801 and hearing the difference.

With regard to new cans, I'm currently really interested in the Hifiman HE-500 and the mr. Speakers alpha dog. Thoughts on one over the other? Especially if I use them occasionally with an iDevice?


500 is the better headphone, but it also requires more to max out potential-wise. The alpha is a closed back so it might be better if you'll be using it on the go at some point. 
 
Jan 26, 2015 at 12:50 PM Post #7 of 10
After further research I've decided I want to go the route of closed back for when I'm at the office; however I can't find a lot of direct comparisons between the SRH1540's and the Alpha Dogs/(Mad Dog Pro's?).  When at work, I typically am boosting my SE425's 21db around 50hz to get the punch in the bass that would be equivalent to my QC15s with a flat eq.  I do love the SE's ability to reproduce the mids that the Bose seem to lose somewhere along the way.
 
I don't know if this makes me a 'basshead', but the Shure SE-425's at that level provide, tight, albeit hard hitting (sub?)bass. If I plug them into my iDevice and play the same song, they sound hollow by comparison.
 
Work PC settings below:
 

 

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