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O2 AMP + ODAC - Page 177

post #2641 of 3784

Please remember this is an 02 ODAC thread not a HE and B22 thread...

 

thanks!

 

A.

post #2642 of 3784

mcandmar,

 

The parts list is extensive, the WIMA caps are one of the largest expense in the list... $40+ just in these caps and there are lots of others.

 

A.

post #2643 of 3784
Quote:
Originally Posted by Xenophon View Post
 

Let me know, very curious .  It certainly won't lack in the power dept.  How many boards is your build, btw?  

Mine is 2 channel.  It sounds fantastic with my LCD 2.2.  Resolution is unreal, O2 sounds bloated.  I guess you need lots of power for Orthos.

post #2644 of 3784
Quote:
Originally Posted by SilverEars View Post

Quote:
Originally Posted by Xenophon View Post

 
Let me know, very curious .  It certainly won't lack in the power dept.  How many boards is your build, btw?  
Mine is 2 channel.  It sounds fantastic with my LCD 2.2.  Resolution is unreal, O2 sounds bloated.  I guess you need lots of power for Orthos.
Yeah I find the O2 to lack microdetails and control with the Alpha Dog, LCD-2, LCD-X, or HE-4. One of the Emotiva amps drives the HE-4 far better than the O2. Maybe current is more of a factor than power per se?
post #2645 of 3784
Quote:
Originally Posted by anthk View Post
 


undue stress? I am curious about this since I suppose even with the adapter, there isnt much weight stressing the port, right?

 

when the input cable gets taut (which happens in my setup from time to time) it applies bending moment to the jack, instead of the usual axial tension.  a bit of speculation on my part.  but the audio corrects itself when i push one way or another on the jack.

post #2646 of 3784

FYI:

 

~~HiFiMan HE-4/5 – They’re rated 86 dB SPL at 1 mW and 38 ohms. To drive them to realistic peaks of 110 dB SPL they need a whopping 200 mW (enough to fry some headphones). That’s about 2.8 V RMS and a peak current of 104 mA per channel in 38 ohms.

 

O2 has :

 

~~Max Output (33 Ohms) 613 mW Max Output (150 Ohms) 355 mW Max Output (600 Ohms) 88 mW.

 

The designer has said many times over that these types of can are some of the hardest to drive.

 

~~it seems the 38 ohm planar HiFiMan HE-4/HE-5LE and 50 ohm HE-6 are especially tough cans that need lots of current.

 

~~The power limits of the O2 exceed the power requirements established for the assumed worst case headphones (HiFiMan planars and 600 ohm version of the Beyer DT880):

 

110 SPL is pretty loud.

 

A.

 

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post #2647 of 3784
Quote:
Originally Posted by miceblue View Post


Yeah I find the O2 to lack microdetails and control with the Alpha Dog, LCD-2, LCD-X, or HE-4. One of the Emotiva amps drives the HE-4 far better than the O2. Maybe current is more of a factor than power per se?

When it comes down to it, it's power. 

 

The loudness it the SPL or dB/mW , which depens on power, and power is multiple of voltage and current.  

 

Although current depends on impedance, it's not just the current(it's with voltage) since the sound output is dB/mW.  W is power.  There are headphons with less impedance that is not that loud, and there are headphones with high impedance that are loud.

 

When you raise the volume, it's amplifying the voltage swing until when it distorts where the supply cannot support it any more.  I guess it would be how much Voltage headroom the amp provides.  Current is just the draw.


Edited by SilverEars - 4/17/14 at 6:41pm
post #2648 of 3784
Quote:
Originally Posted by adydula View Post
 

FYI:

 

~~HiFiMan HE-4/5 – They’re rated 86 dB SPL at 1 mW and 38 ohms. To drive them to realistic peaks of 110 dB SPL they need a whopping 200 mW (enough to fry some headphones). That’s about 2.8 V RMS and a peak current of 104 mA per channel in 38 ohms.

 

O2 has :

 

~~Max Output (33 Ohms) 613 mW Max Output (150 Ohms) 355 mW Max Output (600 Ohms) 88 mW.

 

The designer has said many times over that these types of can are some of the hardest to drive.

 

~~it seems the 38 ohm planar HiFiMan HE-4/HE-5LE and 50 ohm HE-6 are especially tough cans that need lots of current.

 

~~The power limits of the O2 exceed the power requirements established for the assumed worst case headphones (HiFiMan planars and 600 ohm version of the Beyer DT880):

 

110 SPL is pretty loud.

 

A.

 

.

No.  I own a HE-6.  Tried it at the time with O2/ODAC.  It most definitely, empathically does not  work for them.  I don't care what numbers get pulled out of hats but this I know for sure, it's plain and simple to anyone simply trying it.  Not even a question of volume, it sounds like fried crap.

post #2649 of 3784

My Beta 22 is 40Vpp and O2 amp looks like 10Vpp since it's 7Vrms.  O2 amp is current limited to 200mA for very low impedance phones.  For 35ohms or above, the power is limited to Voltage supply and headphones impedance.  


Edited by SilverEars - 4/17/14 at 7:12pm
post #2650 of 3784

Just looked at my LCD-2 specs:

 

  • Impedance:  60 Ohms, purely resistive
  • Efficiency:  90 dB/1 mW
  • Maximum power handling:  15 W (for 200 ms)
  • Optimal power requirement:  1-4 W
post #2651 of 3784

In my post I did mention the he 6's they are even more difficult to drive at 83.5 db/mw and 50 ohm.

(than the 4 or 5's).

 

I would not use an O2 to drive HE6's.

 

My LCD2's are driven my O2's to ear splitting hearing damage levels with aplumb.

 

The O2 is not the perfect amp but for 98% of whats out there it works as well as most anything else out there.

 

A.

post #2652 of 3784
Quote:
Originally Posted by miceblue View Post


Yeah I find the O2 to lack microdetails and control with the Alpha Dog, LCD-2, LCD-X, or HE-4. One of the Emotiva amps drives the HE-4 far better than the O2. Maybe current is more of a factor than power per se?

 

Insensitive low impedance cans are current hungry as a general rule.  That said, I found my AD's to be quite good with my stock O2 (even at unity gain) and very good with the agdr booster board (3.0) and dual LME49990 adaptor in place.  

 

AD's aren't ever going to rival hd800's, for example, when it comes to microdetails, but I haven't noticed anything suggesting a lack of control or power.  Any chance you might elaborate on the latter observation?  I'd be interested to see if I could perceive the same if I knew exactly what you were listening to and for?  Theoretically, my understanding has been that part of the beauty of orthos is that damping is pretty much a non-issue due to the flat impedance curves.  (See Steve Eddy's posts at the bottom of page 2: http://www.head-fi.org/t/617902/effects-of-damping-factor-on-planar-magnetics-orthodynamics/15)

post #2653 of 3784
Quote:
Originally Posted by skeptic View Post
 

 Theoretically, my understanding has been that part of the beauty of orthos is that damping is pretty much a non-issue due to the flat impedance curves.  (See Steve Eddy's posts at the bottom of page 2: http://www.head-fi.org/t/617902/effects-of-damping-factor-on-planar-magnetics-orthodynamics/15)

I thought damping factor was a ratio, and 1 is ideal.  ratio of impedances not about flatness.  If the impedance is high everywhere relative to output impedance, it has high damping factor.  It could still be flat but low everywhere.

 

Even the ones that are not flat can have low damping.

post #2654 of 3784
Quote:
Originally Posted by SilverEars View Post

I thought damping factor was a ratio, and 1 is ideal.  ratio of impedances not about flatness.  If the impedance is high everywhere relative to output impedance, it has high damping factor.  It could still be flat but low everywhere.

Even the ones that are not flat can have low damping.

The point (per Steve Eddy's post no 28 in the link above) is that damping is simply a moot consideration with orthos if the headphone has no resonances in the audible range. A flat impedance curve means no resonances that need to be controlled.
post #2655 of 3784
Quote:
Originally Posted by skeptic View Post


The point (per Steve Eddy's post no 28 in the link above) is that damping is simply a moot consideration with orthos if the headphone has no resonances in the audible range. A flat impedance curve means no resonances that need to be controlled.

Well if you look at a resonance on an impedance vs frequency graph, it's the point where impedance is the lowest.  If the impedance is low everywhere, the damping is still low at any frequency.  If the there is only resonance dip at certain frequency, that means at certain frequency it is not damped well.  This makes sense to me, I still don't get how orthos explanation logically go with that example.

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