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Amp recommendations for Audeze LCD-2 - Page 490

post #7336 of 7753

I believe so if you are talkin phones that have varying impedance on the graph like the dynamics.  Look at planar graphs, it's flat like a resistor(no resonance, no coils?), and phase is flat also.  I agree with more powerful amps not dipping at the low end.  I have never seen portable amps with headphones like LCD or HE-6 being measured, but my guess is that low end will dip based on my experience with portable amps.  I've seen headphones as load on DAPs where the response would skew like crazy, I would guess it would skew on the low end for the big cans.

post #7337 of 7753
Quote:
Originally Posted by Loquah View Post
 

Also, is it safe to assume that headphones have varying efficiency at different frequencies? Would this explain why planars seem to sound more full with more power? I.e. that a more powerful amp can handle less efficiency at lower frequencies?

Some headphones do, but the LCD-2 do not. If a headphone has flat frequency response it means its sensitivity is the same at all frequencies. But its efficiency might not be the same at all frequencies - it might not have a flat impedance curve. However, orthos (including the LCD-2) do have a flat impedance curve, so their efficiency curve has the same shape as their sensitivity curve.

 

Consider the LCD-2: it has flat impedance vs. frequency and also has flat sensitivity vs. frequency. Thus it should require the same power to produce any frequency at the same level.

post #7338 of 7753
Quote:
Originally Posted by Poladise View Post
 

 

Little Dot VI+ - If these had a UK supplier I'd own one already (might take a gamble)

You can't go wrong with that amp. It's amazing!

post #7339 of 7753

I can only afford a Schiit MAGNI right now.

I hope it's good enough for the LCD v2.2.

Has anyone tried this amp with LCD?

post #7340 of 7753
Quote:
Originally Posted by MRC001 View Post
 

Some headphones do, but the LCD-2 do not. If a headphone has flat frequency response it means its sensitivity is the same at all frequencies. But its efficiency might not be the same at all frequencies - it might not have a flat impedance curve. However, orthos (including the LCD-2) do have a flat impedance curve, so their efficiency curve has the same shape as their sensitivity curve.

 

Consider the LCD-2: it has flat impedance vs. frequency and also has flat sensitivity vs. frequency. Thus it should require the same power to produce any frequency at the same level.

 

OK, thanks. I wasn't sure if impedance vs frequency was directly applicable to efficiency as well

post #7341 of 7753
Quote:
Originally Posted by d marc0 View Post
 

I can only afford a Schiit MAGNI right now.

I hope it's good enough for the LCD v2.2.

Has anyone tried this amp with LCD?

As far as I know, it has the most power of any amp in that price range. The LCD-2's are best paired with an amp that can put out between 1 and 4 watts... though these cans are generally forgiving on ideas such as synergy. I'd suggest saving up for something that can do those cans justice. 

post #7342 of 7753
Quote:
Originally Posted by Loquah View Post
 

 

OK, thanks. I wasn't sure if impedance vs frequency was directly applicable to efficiency as well


I believe they're related just not directly, based on my basic understanding of EE. EE gurus correct me if I'm wrong:

 

Consider a hypothetical headphone with flat frequency response and impedance of 50 ohms at 20 Hz and 100 ohms at 1 kHz. The flat freq response means voltage sensitivity is the same at all frequencies. Yet impedance at 20 Hz is half what it is at 100 Hz.

 

Suppose we give this headphone 1 V at 20 Hz and at 1 kHz and see how much power it draws. At 20 Hz, R is half what it is at 1 kHz, so it draws twice the current. Power is i^2 * R, so twice the current squared is a factor of 4, times half the resistance, is twice the power. This this headphone is half as efficient at 20 Hz as it is at 1 kHz.

 

Or do the numbers we get the same result: the headphone is half as efficient at 20 Hz as it is at 1 kHz.

At 20 Hz: i = V / R = 1 / 50 = 0.02 A. P = i^2 * R = 0.02^2 * 50 = 0.02 W.

At 1 kHz: i = V / R = 1 / 100 = 0.01. P = i^2 * R = 0.01^2 * 100 = 0.01 W.

 

With the LCD-2, both the sensitivity AND the impedance curves are flat vs. frequency, so its efficiency must be flat vs. frequency as well. Edit: this is an oversimplification because it ignores HRTF. A headphone with subjectively "flat" frequency response must follow the HRTF curve which isn't flat so the headphone cannot have a flat sensitivity vs. frequency response.


Edited by MRC001 - 4/28/14 at 6:27pm
post #7343 of 7753
Quote:
Originally Posted by MRC001 View Post
 


I believe they're related just not directly, based on my basic understanding of EE. EE gurus correct me if I'm wrong:

 

Consider a hypothetical headphone with flat frequency response and impedance of 50 ohms at 20 Hz and 100 ohms at 1 kHz. The flat freq response means voltage sensitivity is the same at all frequencies. Yet impedance at 20 Hz is half what it is at 100 Hz.

 

Suppose we give this headphone 1 V at 20 Hz and at 1 kHz and see how much power it draws. At 20 Hz, R is half what it is at 1 kHz, so it draws twice the current. Power is i^2 * R, so twice the current squared is a factor of 4, times half the resistance, is twice the power. This this headphone is half as efficient at 20 Hz as it is at 1 kHz.

 

Or do the numbers we get the same result: the headphone is half as efficient at 20 Hz as it is at 1 kHz.

At 20 Hz: i = V / R = 1 / 50 = 0.02 A. P = i^2 * R = 0.02^2 * 50 = 0.02 W.

At 1 kHz: i = V / R = 1 / 100 = 0.01. P = i^2 * R = 0.01^2 * 100 = 0.01 W.

 

With the LCD-2, both the sensitivity AND the impedance curves are flat vs. frequency, so its efficiency must be flat vs. frequency as well.

 

Ah, my confusion was that I don't think I've ever seen a graph of efficiency versus frequency. Or is it called something different?

post #7344 of 7753
Quote:
Originally Posted by MRC001 View Post
 


I believe they're related just not directly, based on my basic understanding of EE. EE gurus correct me if I'm wrong:

 

Consider a hypothetical headphone with flat frequency response and impedance of 50 ohms at 20 Hz and 100 ohms at 1 kHz. The flat freq response means voltage sensitivity is the same at all frequencies. Yet impedance at 20 Hz is half what it is at 100 Hz.

 

Suppose we give this headphone 1 V at 20 Hz and at 1 kHz and see how much power it draws. At 20 Hz, R is half what it is at 1 kHz, so it draws twice the current. Power is i^2 * R, so twice the current squared is a factor of 4, times half the resistance, is twice the power. This this headphone is half as efficient at 20 Hz as it is at 1 kHz.

 

Or do the numbers we get the same result: the headphone is half as efficient at 20 Hz as it is at 1 kHz.

At 20 Hz: i = V / R = 1 / 50 = 0.02 A. P = i^2 * R = 0.02^2 * 50 = 0.02 W.

At 1 kHz: i = V / R = 1 / 100 = 0.01. P = i^2 * R = 0.01^2 * 100 = 0.01 W.

 

With the LCD-2, both the sensitivity AND the impedance curves are flat vs. frequency, so its efficiency must be flat vs. frequency as well.

Yes, since R is constant since the impedance is flat throughout the spectrum.  That means it only depends on voltage even for efficiency, although V^2.  This all depends on if voltage is constant at all frequencies.  

 

What I'm not understanding is the FR graph not being flat, why is that? 

post #7345 of 7753
Quote:
Originally Posted by SilverEars View Post
 

Yes, since R is constant since the impedance is flat throughout the spectrum.  That means it only depends on voltage even for efficiency, although V^2.  This all depends on if voltage is constant at all frequencies.  

 

What I'm not understanding is the FR graph not being flat, why is that? 


Unlike loudspeakers, a headphone with subjectively flat response does NOT have objectively flat response. Because the headphone is attached to your head it has to compensate for sounds traveling through your head and bypassing your ears in ways that actual sounds in the real world don't. That's called the HRTF curve. Essentially, the headphone has to have a response that is the opposite of the HRTF curve in order to sound subjectively "flat" or neutral to the listener.

 

That means a headphone with subjectively "perfect", neutral flat response (the LCD-2 is close to this) does NOT have a flat sensitivity vs. frequency curve. Its sensitivity is different at different frequencies, and since the LCD-2 impedance is actually flat, its efficiency is NOT flat. Thus it requires more power at some frequencies than others.

 

Some loudspeakers also need to have non-flat response in order to have flat response at the listener position. For example, Magnepan 3.6 speakers have a response bump at 50 Hz. You place them the right distance from the back wall so the back wave is 180* out of phase with the front wave which cancels the bump. If you measure them near-field, you see a big bump at 50 Hz, but if you measure them far-field at the listener position you get flat response (if they're correctly positioned). Similar concept as headphones with HRTF corrected response, just a different application.


Edited by MRC001 - 4/28/14 at 6:32pm
post #7346 of 7753
Quote:
Originally Posted by d marc0 View Post
 

I can only afford a Schiit MAGNI right now.

I hope it's good enough for the LCD v2.2.

Has anyone tried this amp with LCD?

 

I think you will enjoy it as long as your DAC is better than the Modi DAC (which is slightly lacking detail and energy vs an AE D1 or uDAC-2 SE).

post #7347 of 7753
Quote:
Originally Posted by HeadphoneAddict View Post

I think you will enjoy it as long as your DAC is better than the Modi DAC (which is slightly lacking detail and energy vs an AE D1 or uDAC-2 SE).

Thank you! I'll check them out...
post #7348 of 7753
Quote:
Originally Posted by vkalia View Post
 

^^^    Lyr with Amperex tubes.    I had the original tubes and swapped them out a couple of days ago and oh. my. lord.....

 

What was the difference you noticed?

 

Quote:
Quote:
Originally Posted by Poladise View Post
 

 

Little Dot VI+ - If these had a UK supplier I'd own one already (might take a gamble)

You can't go wrong with that amp. It's amazing!

 

Yeh, I bet it is. I've just become a little paranoid about shipping tube amps overseas. I'm very close to ordering one though.

post #7349 of 7753
Quote:
Originally Posted by PTom View Post
 

So the updated list of the most widely recommended amps for the LCD 2 within different price ranges is:

 

Below $2000:

 

- Auralic Taurus

- Beta 22

- Burson Soloist

- Burson Conductor (DAC/amp)

- Bryston BHA-1

- Decware Taboo MK II/MK III
- M2tech Marley

 

Below $1000:

 

- Audio GD SA31SE/MFB 6/Master 9

- Audio GD NFB 28 (DAC/amp)

- Centrance DACmini (DAC/Amp)

- Lake People G109

- Little Dot  MKVI+/MKVIII

- Meier Concerto/Classic

- Nuforce Icon DAC (DAC/amp)

- Schiit Mjonir/Lyr

- Violectric V200 

- Yulong A18

 

Below $200:

 

- O2

- Schiit Magni/Vali

 

As mentioned before, I'm looking for the most widely recommended amps for the LCD 2. Any more suggestions? Are there any in the above list that should be removed since they are not universally praised with the LCD 2 or are uncommon?

 

Update

 

Added: 

 

- Bryston BH1
- Auralic Taurus
- M2tech Marley

- Yulong A18

- Decware Taboo MK II/MK III

- Nuforce Icon DAC 

- Centrance DACmini (DAC/Amp)

Based on the above nominations, I've started a poll to find Head Fi's favourite amp to drive the LCD 2.

 

To vote in the $200-$1000 category click on the following link:

 

http://www.head-fi.org/t/716576/head-fis-favourite-amp-for-the-audeze-lcd-2-200-1000-poll

 

For the $1000-$2000 category click on the following:

 

http://www.head-fi.org/t/716577/head-fis-favourite-amp-for-the-audeze-lcd-2-1000-2000-poll

post #7350 of 7753
Quote:
Originally Posted by Poladise View Post
 

What was the difference you noticed?

 

I didnt do an A/B comparison with specific songs, so can only provide general impressions, based on long-term listening at different levels before and after.   

 

With the Amperex, the Lyr started sounding more like a single-ended-triode tube amp - voices had a fullness that sounded closer to live than recorded, instruments gained a presence that they did not have before.  I am guessing the lower mids gained some.    In short, the music has gained more "weight", realism and greater dynamic impact/slam.    

 

I am actually quite surprised - i was expecting a much smaller difference (I am the guy that typically takes all the talk about huge differences between amps, DACs, cables, etc with several grains of salt).


Edited by vkalia - 4/29/14 at 10:24am
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