[gahung]

The issue is amp manufacturer don't highlight the output current. So what way could one tell if if the amp will be suitable for low impedance headphones.

Yeah, I don't know the answer for this my friend, but for me I have been buying used amps to try as many amps as I can with limited budgets. Sometimes reviews are helpful but people have different taste and most of the time they mislead me. I had design some non audio amplifiers and I will look at the datasheet a little when I looked into an amp but it's not everything. In addition, many experienced audiophiles have proved that specs is not everything(look at those "duplicate" designs on ebay that is far below the performance of the original). I think I am trapped in a loop now.

 

[headwhacker]

  Easy to drive does NOT mean any amplifier with enough power can drive it WELL.
From my experience, the low impedance high sensitivity phones are the hardest to find a matched amp since it needs a lot of CURRENT. (P = I^2*R, so to output the same power, low impedance hp needs more current. I know it's too simplify but that's an easy way to look at it. I don't see why the output power matters that much to some people)
For high impedance phones, it may need high output power to have sound but generally they are really easy to drive(despite the picky HD800), but for a long time, I have had a hard time finding a good amp for planners.
As far as I know Dr. Bian Fang is one of those who will laugh at people driving headphones using their computer sound cards, ( yes, I go to Chinese hp forums a lot) and from how much money he spent on the EF1000 you can tell what's his attitude towards driving his headphone. I am not saying that some budget amps are bad or something, and I believe there are many overprice amps in the market so price doesn't mean anything. But really, driving a flagship planner like this using a $100 dollar amp? Sounds to me driving a Ferrari but get the regular gas and a set of $400 all season tires.

 
The key to getting the correct amp is to know the power it can deliver at a given headphone load(impedance). For HE-1000, 1W of power @ 35 ohms has enough current to drive it at 120dBSPL. But 1W maximum @ 16Ohms is barely enough.
 
Common mistake and confusion is to just look at the total power output but at a different impedance of the headphone intended to be driven. Worst, manufacturer will try to hide as much as they can and give bogus or confusing numbers.  Example is chord hugo in moon audio's page, it says "Headphone output: 110dB SPL into a 300ohm headphone load". It doesn't mean anything until it state the sensitivity of the headphone load they use to come up with that number. How hard is it to just publish the maximum power output at a given load?
 
Other manufacturers manage to give the maximum power output at different headphone loads. This is the most important information a user need because amplifiers react differently with different load.  More important than THD numbers in my opinion.

 

[potkettleblack]

Had an 800 for months compared an 02 with two cambridge audio amps and a bryston and preferred my o2
 
Also preferred my o2 with the lcd 3's over a bryston
 
And I tried it with the he560's and preferred the o2
 
As far as I'm aware the below is a beast:
 

 
 
I believe your luxury car analogy isn't correct - at least in my world and the other person I was with that agreed with me

 

[gahung]

   
The key to getting the correct amp is to know the power it can deliver at a given headphone load(impedance). For HE-1000, 1W of power @ 35 ohms has enough current to drive it at 120dBSPL. But 1W maximum @ 16Ohms is barely enough.
 
Common mistake and confusion is to just look at the total power output but at a different impedance of the headphone intended to be driven. Worst, manufacturer will try to hide as much as they can and give bogus or confusing numbers.  Example is chord hugo in moon audio's page, it says "Headphone output: 110dB SPL into a 300ohm headphone load". It doesn't mean anything until it state the sensitivity of the headphone load they use to come up with that number. How hard is it to just publish the maximum power output at a given load?
 
Other manufacturers manages to give the maximum power output at different headphone loads. This is the most important information a user need because amplifiers react differently with different load.  More important that THD numbers in my opinion.

You are right about the sensitivity. That is a big consideration when talking about headphones. Maybe I am wrong about the current but my main concern to the performance of analog amplifier is if the transfer function is linear. Even though an amp may have enough peak voltage or current to amplify it so that its signal not rolled off(for small signal amplification, it is almost impossible so I don't even consider that),the signal can be greatly distorted at some frequency which is not we want for a audio equipment.
I agree that some specs are misleading but maybe that's a common marketing method for manufactures? I don't know.
THD is important for high sensitivity headphones since the white noise from other components are more obvious.
Correct me if I am wrong.

 

[money4me247]

potkettleblack, blind test?

 

[potkettleblack]

I sustained opacification of both of my eyes during the second gulf conflict, due to radiation. I could only determine which amp was which (if I wanted to) by trying to pick them up.
 
Does this qualify?

 

[mowglycdb]

@potkettleblack, blind test?

His opinion is valid, I listened to the combo o2/odac and it sounded nice on my LCD-2(90dB/mW 50ohm), but I did feel it had some THD+N on high volumen, something that I'm sensible to over time.
 
If you we're listening to the old LCD-3 91dB/mW 50ohm, it should be noticeble at high volumes. I assume you listen at safe volume. At close to 113dB it should reach 1% THD+N   or you have LCD-3F

 

[headwhacker]

 
His opinion is valid, I listened to the combo o2/odac and it sounded nice on my LCD-2(90dB/mW 50ohm), but I did feel it had some THD+N on high volumen, something that I'm sensible to over time.
 
If you we're listening to the old LCD-3 91dB/mW 50ohm, it should be noticeble at high volumes. I assume you listen at safe volume. At close to 113dB it should reach 1% THD+N   or you have LCD-3F

 
I have the 560 and it sounded great on O2. On several classical music, it felt like O2 is running out of juice rather than hearing noise or distortion even at max volume level.
 
You must be hearing clipping noise. What is the voltage level of the source you use and the gain O2 is set when you hear noise?

 

[jude]

@potkettleblack, blind test?

 
That's a discussion you can take here, but not have in this thread.
 
He likes his O2--a lot. If he wants to drive an HE-1000 or LCD-3 with it, and is happy with the results, that's all that matters.
 
Now let's get this thread back on topic.
 
EDIT: Of course, the discussion about whether or not the O2 will drive the HE-1000 (like in the post above) is on-topic discussion for this thread.

 

[pearljam50000]

delete

 

[potkettleblack]

 

[money4me247]

lol just a simple question. not trying to derail the thread or anything. just curious if the comparison was done blinded or not.

 

[goldendarko]

Lol wut da...

 

[potkettleblack]

It was supposed to suggest that Jude is saving the day again like the eagles from the Hobbit.

 

 

[XVampireX]

 
It was supposed to suggest that Jude is saving the day again like the eagles from the Hobbit.

 

 
https://www.youtube.com/watch?v=Wx3by7ZaaZA