[adamlr]

sorry for the weird text layout - my computer is being weird...
 
headphones, and all drivers of any kind "receive" ac, alternating current - which is what music is. a dc signal
 will kill most any driver. the inner workings of the 02 are powered by dc voltage (the only kind a battery 
knows how to supply. but "the signal sent to the headphones" will definitely be ac.
the 02 runs on ac power. 14-20 Volt. that why you need the adapter - to turn 110/220V ( depending on where
 you live) into 20V (for example).
i imagine theres a componenet that converts the ac into dc in order to charge the batteries...
gain settings are there to be played with. i have mine on unity gain - always. i rarely use the x2.5 option.
if yours in completely "regular" from the site, x2.5 will be the low gain, and x6 (i think) is the high gain - which will]
 definitely be too much for your grados.
if you feel that x2.5 is too much aswell, you can easily make unity gain an option with some super easy diy - why not cross that bridge
 when you get there?
i say listen first and see. if on the low gain setting you cant listen at a comfortable level with the pot at (atleast)
 9 oclock, then maybe you should think of a little diy - the further you twist your volume pot right, the less imbalance
 between the channels you see.
but if you can twist your pot to 9 oclock or more and the volume if good to your ears, i imagine youll be fine.

 

[Sam21]

headphones, and all drivers of any kind "receive" ac
 
Wrong, Headphones receive a varying DC current. it is like a sinusoidal wave with varying wavelength and amplitude over time.

 

[adamlr]

  headphones, and all drivers of any kind "receive" ac
 
Wrong, Headphones receive a varying DC current. it is like a sinusoidal wave with varying wavelength and amplitude over time.

the driver works by pushing air. it moves forward, and backward. an ac current, say a sine wave at 1 KHz will make the driver move backwards AND forwards 1000 times per second. a dc current doesnt alternate - direct current. feeding a driver dc current will make the driver move backwards only, or forwards only - which is a sure way to kill the driver. that why distortion (the unintentional type) is so damaging to the pa systems. "clipping" creates small amounts of dc current at the "clipped" peaks, and if the technicians arent carefull - drivers may blow.
 
music and sound are composed of frequencies. i,e how often the signal alternates. if a 100 Hz tone is played, the driver will alternate 100 times.
 
theres no such thing as "varying dc current". by definition, direct current DOES NOT ALTERNATE.

 

[adamlr]

from wikipedia: 
"Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries,thermocouples, solar cells, and commutator-type electric machines of the dynamo type... ... The electric current flows in a constant direction, distinguishing it from alternating current (AC)."

 

[Sam21]

yes but a DAC chip outputs different values of DC voltages at any given time...it is DC current but varies at any given time..in mathematical terms it is like a sinusoidal wave that is smooth.

 

[adamlr]

mate. a "sinusoidal" wave is another way of saying "sine wave". a sine wave alternates between positive and negative polarity at a given frequency. i guess you could say that a sine wave "alternating" at 0 Hz is like a direct current - but thats just a backwards way of seeing it.
a smooth sinewave isnt really a sinewave is it? 
direct current doesnt change its polarity... it remains positive (if im correct). if it doesnt change - you simply cannot hear it...
 
from wiki:

note the difference between the green line and the red line...
 
im sorry, but will have to continue this at some other time, im done for the night...

 

[adamlr]

one more thing actually....
 
you mentioned dacs. im assuming your talking about the 2Vrms standard output?
rms means in laymens terms "average". the 2V will also fluctuate depending on the music...
 
understand. the dac takes data and translates it into an analogue signal - which is electricity. 
said signal passes on to be amplified and eventually to move the membrane. in order to create movement, the polarity has to change, or the membrane will only move in one direction.

 

[Ritwik]

I have received my Grado SR325e and O2+ODAC Combo a week back. So as you can all understand, I was busy last week experimenting.There are some noticeable attributes what I have found so far. I am listing them down.


 


My set:


Source: Apple Music(256 kbps AAC)


Player: iTunes in laptop/ Apple Music in iPhone 5s


DAC/AMP: JDS Labs O2+ODAC Combo (I only use low-gain)


Headphone: Grado SR325e Prestige series


 


My findings:


------------------


1. O2+ODAC is treble heavy(NwAvGuy said multiple times that it is neutral). The hi-pitch growls and shrills are crystal clear. I listen to post-hardcore bands like UnderOATH, Papa Roach and the output is tremendous.But sometimes the treble gets too sharp and it feels more of a bullet and less of a song.  


2. Whenever I listen to Adele(e.g. Don't you remember), I find the output to be not full. It lacks bass and sometimes the treble gets way sharper making the overall experience one-sided. Whenever I listen to the same song from my iPhone 5s without any amping, the overall performance seems better. With amp, the vocal is crystal clear but the overall output lacks fullness. It feels a bit cold sometimes.


3. People say Grado is only for metal. But I find Diana Krall or Adele sound supreme with these cans. Problem is if I use amp, I am not getting that out of the world feeling. 


4. SO I did the easiest thing possible. I changed the default EQ in iTunes.And now the output is far better with amp. But still I'd expect more.  


5. Out of context but still: _/\_ DAC in iPhone 5s _/\_


 


Can anyone please tell me how to get a better overall experience? I know Grado is not famous for bass. But if I am more than happy with the performance without amp, I should be happier with the performance with amp . But for some sound signature, i am not.


 


Thanks in advance!

 

[Mmet]

  I have received my Grado SR325e and O2+ODAC Combo a week back. So as you can all understand, I was busy last week experimenting.There are some noticeable attributes what I have found so far. I am listing them down.
   
  My set:
  Source: Apple Music(256 kbps AAC)
  Player: iTunes in laptop/ Apple Music in iPhone 5s
  DAC/AMP: JDS Labs O2+ODAC Combo (I only use low-gain)
  Headphone: Grado SR325e Prestige series
   
  My findings:
   

---

 
  1. O2+ODAC is treble heavy(NwAvGuy said multiple times that it is neutral). The hi-pitch growls and shrills are crystal clear. I listen to post-hardcore bands like UnderOATH, Papa Roach and the output is tremendous.But sometimes the treble gets too sharp and it feels more of a bullet and less of a song.

 
  2. Whenever I listen to Adele(e.g. Don't you remember), I find the output to be not full. It lacks bass and sometimes the treble gets way sharper making the overall experience one-sided. Whenever I listen to the same song from my iPhone 5s without any amping, the overall performance seems better. With amp, the vocal is crystal clear but the overall output lacks fullness. It feels a bit cold sometimes.
  3. People say Grado is only for metal. But I find Diana Krall or Adele sound supreme with these cans. Problem is if I use amp, I am not getting that out of the world feeling. 
  4. SO I did the easiest thing possible. I changed the default EQ in iTunes.And now the output is far better with amp. But still I'd expect more.  
  5. Out of context but still: _/\_ DAC in iPhone 5s _/\_
   
  Can anyone please tell me how to get a better overall experience? I know Grado is not famous for bass. But if I am more than happy with the performance without amp, I should be happier with the performance with amp

. But for some sound signature, i am not.
   
  Thanks in advance!

a bright headphone with a neutral to bright amp is not balanced compo i think ... so you can try to change either the amp or the headphone ....

 

[MrMateoHead]

  I have received my Grado SR325e and O2+ODAC Combo a week back. So as you can all understand, I was busy last week experimenting.There are some noticeable attributes what I have found so far. I am listing them down.
   
  My set:
  Source: Apple Music(256 kbps AAC)
  Player: iTunes in laptop/ Apple Music in iPhone 5s
  DAC/AMP: JDS Labs O2+ODAC Combo (I only use low-gain)
  Headphone: Grado SR325e Prestige series
   
  My findings:
   

---

 
  1. O2+ODAC is treble heavy(NwAvGuy said multiple times that it is neutral). The hi-pitch growls and shrills are crystal clear. I listen to post-hardcore bands like UnderOATH, Papa Roach and the output is tremendous.But sometimes the treble gets too sharp and it feels more of a bullet and less of a song.

 
  2. Whenever I listen to Adele(e.g. Don't you remember), I find the output to be not full. It lacks bass and sometimes the treble gets way sharper making the overall experience one-sided. Whenever I listen to the same song from my iPhone 5s without any amping, the overall performance seems better. With amp, the vocal is crystal clear but the overall output lacks fullness. It feels a bit cold sometimes.
  3. People say Grado is only for metal. But I find Diana Krall or Adele sound supreme with these cans. Problem is if I use amp, I am not getting that out of the world feeling. 
  4. SO I did the easiest thing possible. I changed the default EQ in iTunes.And now the output is far better with amp. But still I'd expect more.  
  5. Out of context but still: _/\_ DAC in iPhone 5s _/\_
   
  Can anyone please tell me how to get a better overall experience? I know Grado is not famous for bass. But if I am more than happy with the performance without amp, I should be happier with the performance with amp

. But for some sound signature, i am not.
   
  Thanks in advance!

 
The problem is that you are listening to Grados which you don't seem to like . . . in the long-run, far easier, and far cheaper, to change your speakers than attempt to change your sound by looking for amps with the right "distortion" profile. Just sayin'

 

[Ritwik]

That's not at all true. I am loving my Grado from day 1. It's the performance of the amplifier that is making me puzzled.

 

[MrMateoHead]

  That's not at all true. I am loving my Grado from day 1. It's the performance of the amplifier that is making me puzzled.

Other than issues with recordings, like clipping from excess dynamic compression, the speakers are typically 99% of the problem. The O2 should be no more "treble heavy" than the recording + speakers. Sorry.

 

[henkie196]

It's all relative. The O2 is supposed to be neutral, i.e. no colouration of the sound. However, if you are used to listening to an DAC+amp that colours the sound to be a bit warmer, the O2 will sound bright or cold in comparison. If this is combined with headphones that are already somewhat on the brighter side of things, the treble might become too much.
 
If the DAC and amp are indeed neutral, the brighter sound is actually what your headphones sound like. Technically, one could say that you should look for a more pleasant sound signature from the headphones themselves, as there is nothing wrong with the DAC/amp itself. On the other hand, if you like the sound of your Grados straight out of your iPhone, you could also ask yourself why you'd even bother with an external amp and possible uncomfortable sound signatures combinations. Or you could look for a DAC/amp with your prefered sound signature, or synergy as they like to call it here. Beware that this can be a rather lengthy and expensive pursuit.

 

[Ritwik]

I bought the DAC+AMP because it's written in almost all reviews that within 300$, it's the best you can get. And I have as a friend an international death metal band member in FB who suggested me this amp. So I didn't think much. I wanted to get the best sound in 600$ setup .
 
This is my first DAC+AMP combo. I like it with no doubt. But I am more amused with the prowess of iPhone DAC. Anybody who will listen to Adele's "Don't you remember" by using both iPhone and this DAC+AMP from Apple Music, will find that out.

 

[ostewart]

Lets revive this thread, just finished building my HeadNHifi desktop O2 amp, it has RCA inputs and outputs, 6.3mm jack on the front and power jack on the back. My new reference stack is the O2 paired with the OL DAC.

Built with 1x and 4x gain

http://www.headnhifi.com/objective2