[r010159]

I hope all is doing well! I have a question. I am looking at a second pair of headphones for my mother. She does appreciate good headphones. I am deciding between the HD600s and the HE-4s. Do any of these two work well with the O2D? Anyone know the difference between the two?
 
Bob Graham

 

[skeptic]

  I hope all is doing well! I have a question. I am looking at a second pair of headphones for my mother. She does appreciate good headphones. I am deciding between the HD600s and the HE-4s. Do any of these two work well with the O2D? Anyone know the difference between the two?
 
Bob Graham

 
Difference boils down to one being a high ohm dynamic and the other a low ohm ortho.  While I like my bedside odac->o2 quite well with my alpha dogs, westone 4's and, to a lesser extent, my dt880's, I don't care much at all for the combo with my hd650's or hd800's.  The Senns just sound much better from my bottlehead amps.  hd600's are fairly similar to hd650's, so I wouldn't recommend either to be paired with the O2D.

 

[PTom]

Anyone tried the O2 with the beyerdynamic T1? Any good?

 

[headwhacker]

Anyone tried the O2 with the beyerdynamic T1? Any good?

O2 can properly drive T1. I use DX50 as source and the 2.5X gain provides loud enough but noise/distortion free sound. O2 is quite flat and neutral. T1 will let you hear what the source feeds it thru O2.

 

[PTom]

The epiphany acoustics O2 is battery powered so I am wondering if it will have as much power as say the FiiO E9, matrix mstage, schiit magni etc.

 

[Dano91]

  I hope all is doing well! I have a question. I am looking at a second pair of headphones for my mother. She does appreciate good headphones. I am deciding between the HD600s and the HE-4s. Do any of these two work well with the O2D? Anyone know the difference between the two?
 
Bob Graham

I'm using HD 600 with O2+odac and I simply love that combination. Difference between those two is that hd 600 are more neutral/linear, easier to drive and more comfortable for long listening, HE-4 has better bass.

 

[Dano91]

  The epiphany acoustics O2 is battery powered so I am wondering if it will have as much power as say the FiiO E9, matrix mstage, schiit magni etc.

I don't know about matrix, but E9 and magni has more power, but the real question is, if you really need that more power? Simple answer is no, you don't, because O2 can drive 99% of all headphones to crazy  volumes.. (That can be calculated with quite simple math)

 

[PTom]

Thanks for the reply Dano91. My main concern is that the T1 has a really high impedance i.e. close to 1400 ohm at mid bass frequencies (http://www.innerfidelity.com/images/BeyerdynamicT1.pdf) so I'm guessing they would require rather large voltages to drive properly?

 

[chococya96]

It seems like O2+ODAC combo is not self-powered via AC instead, uses USB as power source (it only powers the amp).
 
I always had a impression that it was self-powered but... Oh stupid me.

 

[jring]

  It seems like O2+ODAC combo is not self-powered via AC instead, uses USB as power source (it only powers the amp).
 
I always had a impression that it was self-powered but... Oh stupid me.

 
In the O2+ODAC combo the battery space is usually taken up by the ODAC board (although other solutions exist either with a larger box or creative packaging). The O2 part is then powered by the wall wart (or batteries if these are still present) and the ODAC is always USB powered.
 
Joachim

 

[Dano91]

  Thanks for the reply Dano91. My main concern is that the T1 has a really high impedance i.e. close to 1400 ohm at mid bass frequencies (http://www.innerfidelity.com/images/BeyerdynamicT1.pdf) so I'm guessing they would require rather large voltages to drive properly?

Not really, in fact voltage requirement is depended only on headphone's sensitivity which doesn't necessarily correlates with hp's impedance curve. Look here: http://doctorhead.ru/upload/iblock/efd/fr.png
At 500 Hz it has higher sensitivity than on 1 kHz despite being higher impedance on 500 Hz.
 
In worst case they measured sensitivity of 96 dB/V and at best 109.9 dB/V. Which means that for playing 110 dB you would need 5.01 V in worst case and 1.01 V in best case and in average it's 3.13 V. O2 amp max output is 7.15 V, but exact number depends on used source and gain.
Feel free to ask more if you are interested
 
P.S: Beyers T1 has a relatively hot treble which when used with O2 can make some not very pleasing sound.

 

[Xenophon]

I own the Epiphany acoustics DAC/Amp implementation of the O2 and while it's extremely good for its price, it's not the end-all in terms of quality amplification.  You'll be able to drive most headphones loud, yes.  But loudness is only part of the equation, as are voltage swing and current considered independently.
 
I owned the DT-880's in 600 ohm, sold them since as I upgraded my headphones and after auditioning I came to the conclusion that the BD 'house sound signature' was not my cup of tea (just a matter of taste, no reflection on quality).  
 
They worked well with the O2-stack but occasionally it just ran out of steam.  You don't just need gain (voltage), the power source needs to be able to supply sufficient power to meet demand and with high impedance cans or low sensitivity ones, especially listening to music with a large dynamic range (classical) the O2 just isn't enough, distortion will start popping up and hitting the gain button only makes that worse, what you need is power on tap and that simply doesn't come in small packages with small power supplies, sorry.  Take a look at the distortion graphs on the designer's site.
 
Having said this, I still use this little dac/amp daily in my office and it's a sight better in terms of SQ compared to the FiiO combo imho.

 

[PTom]

From the last two posts it seems that it would be better to go for another amp for my T1. Any suggestions in the under £200 ($300) range?

 

[Xenophon]

Sub 200 GBP will be tough for something half decent, I'm assuming you only need the amp, not the DAC.  
 
I'd advise the classifieds here or ebay, what you could also do is pick up a used stereo receiver or small low-power speaker amp and run the T1 from the speaker taps but I can't recommend anything in particular as I don't own the T1 so can't say anything about good pairings.  
 
Caution:  if you go the speaker amp way you can save lots of cash and get great sound BUT research it well and be sure to understand all aspects of it before proceeding as this has the potential to blow up your eardrums, the headphone and/or the amp.

 

[Dano91]

Regarding O2 power capabilities I have one question - according to designer's site, O2 is able to produce 7.15V when powered from AC. In a same time designer states that max input voltage before clipping is 7.15 / GainValue.
Does this mean that when used with ODAC, which has 2V output and standard O2 gain options (2.5x and 6.5x) you can produce 5V on output at 2.5x gain? This will also mean if we want to reach that 7.15V limit with 2.5x gain, we have to use some other source capable of outputting cca 2.8V ?