[justanut]

Grabbed from another thread:
 
 
if two phones have the same sensitivity, the one with lower impedance is harder to drive.

Say you have a source of 1.4Vrms output, two phones with 16 and 32ohms impedance. @1kHz, Current through the 16ohms one is 1.4/16=87.5mA, and 1.4/32=43.75mA for the 32ohms one. The power draw from the 16ohms one is then P=I^2*Z=0.0875^2*16=122.5mW, and 0.04375^2*32=61.25mW. You can see that the 16ohms phone is actually drawing more current and power from the source.

The reason why we think low impedance phones are easier to drive is that they usually comes with high sensitivity (>100 spl). It's just those low impedance and low sensitivity phones that are particularly hard to drive.

 

Which might explain why the T5p is so notoriously difficult to drive... Anyway I'm finding the treble better controlled on the iQube than when paired with the RSA Shadow~ No more cringe moments at least thus far...

 

[ryflmn]

I am quite pleased with the clarity of my t50p's.  I do not consider them veiled but rather quite detailed.  I am a big fan of my beyer's.  As some have mentioned there may be some quality control issues with these considering the wide array of opinions.  Maybe I'm one of the lucky one's to have a gotten a good set.  By the way my serial is in the 10300's and I haven't had any issues with placement or fit and my hat size is 6 7/8.  In fact, I find these to be quite comfortable.
 
I'm really interested in hearing more about how these phones are effected by amping.  If anyone has any experiences, I would love to hear them.

 

[ryflmn]

Addendum to my last post:  If anyone has experience with amping the t50p, would you mind giving your impressions and the amps used?

 

[justanut]

It could be that those of us who are disappointed have had exposure to better cans and are spoiled by those~ They're not bad, just not $250 worthy... at least not yet. I'm putting all my hopes into the 400hr burn in suggested on some china sites
 
Mine's 10339...

 

[AudioGlow]

I've only got about 8 hours in on my T50P's and I wouldn't call them veiled at all. Almost the exact opposite. I know they're not broken in yet, but they seem very revealing and only lacking in bass weight. When amped on my Bellari HA540 they come alive. It really is a drastic improvement from the ipod alone. The ipod provides plenty of volume, but not enough current to really control them well. Still though, I think they are a very pleasing listen even on ipod alone. They need more hours on them before I review them completely though.

 

[Henri]

Hi, I am new to Head-fi and this is my first post.
 
I am experiencing the same issue with my T-50p. I would not call myself an audiophile though I own quite a lot of headphones ranging from in-ears Shure SE530 to AKG-Q701.
I bought them expecting lots of clarity and so far, I am hugely disappointed after about 60 hours of burn-in. Maybe I have been spoiled by my experience with the AKG but the Beyerdynamics are failing hugely to please me. As said before, they sound veiled. The bass is quite muddy and they utterly lack clarity.
I compared them side by side with other phones with amp and no amp. I use an optical output from  my computer to an Onkyo  TX-SR308, a Fiio E11 and an Iphone 4. The result is the same: total lack of clarity.
The headphones I used for comparison are the ATH-ESW9, the Beyerdynamics DT880-32Ohms and the Ultrasone HFi-15G.
In each call, the other phones are clearer. My Shure SE530  are also delivering much better.
I do not know if it is due to a bad placement on my ears because I have tried shifting them many times without improvement.
It may be indeed a problem of quality control. I hope it is, otherwise my hearing might be heavily defective.
I bought them hoping for a large soundstage but it is not there either. I bought them straight from Amazon and they look like the real stuff.
I am now considering either a refund or a replacement.
What would anyone suggest? Is it worth giving it a second chance?
Edit: 01/16/2012
Today, I wrote a review on Amazon, comparing it with the ATH-ESW9A. Although the sound of the T50p has somehow improved over the weekend when I kept it plugged on Pink Noise all the time, they still were not giving me the feeling of airiness I got from the ATH. I am now set to return it for refund.