CHORD ELECTRONICS DAVE
Dec 12, 2016 at 3:12 PM Post #6,076 of 25,747
   
The abyss is an easy load to drive with an impedance of 46 ohms, so there is no way Dave will run out of current - so you can run Dave at +4dB and the output from Dave will be linear. So assuming you are not running above +4dB, there is plenty of drive in voltage and current available.
 
The interactions of headphone and outputs are not simple, and for sure a lack of distortion will make it sound brighter, as low order (particularly 2nd) harmonics fatten up the sound. An additional factor is output impedance in terms of damping factor. A high damping factor better controls the drive unit, making the bass sound fast, tight and somewhat leaner. Additionally, low output impedance itself reduces distortion. The load presented by a headphone varies with cone displacement, so the impedance itself varies with amplitude. Now with an amp and cables that have zero impedance, this variation in load has no effect - no increase in distortion. But with a finite cable and amp impedance, you will increase distortion, and because it depends upon bass, this will fatten up the sound too, making the bass much bigger.
 
Now Dave has only 55 milli ohms of output impedance (0.055 ohms), so it has a substantial damping factor (much lower than any other amp I have seen), which will ensure the bass is tight and accurate; also it will almost eliminate distortion due to load non-linearity (assuming you have a low impedance cable too).
 
My view is if a headphone is too lean, then use good EQ - or even better, use headphones that innately have more bass to suit your taste. The problem with using distortion to fatten up the sound, is that everything then sounds the same - big and fat. I want my music to be fast, tight and lean when the musician wanted that sound - and big and fat when that was the intent. You can only get that when the system is truly transparent.
 
Rob

The abyss is 46 ohms but the LCD-4 is 200 and I must say it is tough to drive,I do wonder what Rob thinks about the LCD-4 with the Dave direct
 
Dec 12, 2016 at 3:26 PM Post #6,077 of 25,747
LCD 4
Specifications
Style Open circumaural
Transducer type Planar magnetic
Magnetic arrays Double Fluxor magnets
Magnet type Neodymium
Transducer size 106 mm
Maximum power handling 15W (for 200ms)
Sound pressure level >130dB with 15W
Frequency response 5Hz – 20kHz extended out to 50kHz
Total harmonic distortion <1% through entire frequency range
Impedance 200 ohms
Efficiency 97dB / 1mW
Optimal power requirement 1 – 4W

OPTIMAL POWER 1 - 4W

Do the Dave provide this optimal power? I think so...
 
Dec 12, 2016 at 3:32 PM Post #6,078 of 25,747
  The abyss is 46 ohms but the LCD-4 is 200 and I must say it is tough to drive,I do wonder what Rob thinks about the LCD-4 with the Dave direct

 
Here are the power requirements of both headphones.
 
Abyss AB-1266
e33de3c7_abysspowerrequirements.png
 
Audeze LCD-4
9488832e_lcd4.png
 
As you can see, the Abyss is far harder to drive, primarily due to its much lower sensitivity.
 
Dec 12, 2016 at 3:36 PM Post #6,079 of 25,747
LCD 4
Specifications
Style Open circumaural
Transducer type Planar magnetic
Magnetic arrays Double Fluxor magnets
Magnet type Neodymium
Transducer size 106 mm
Maximum power handling 15W (for 200ms)
Sound pressure level >130dB with 15W
Frequency response 5Hz – 20kHz extended out to 50kHz
Total harmonic distortion <1% through entire frequency range
Impedance 200 ohms
Efficiency 97dB / 1mW
Optimal power requirement 1 – 4W

OPTIMAL POWER 1 - 4W

Do the Dave provide this optimal power? I think so...

 
The DAVE, according to Chords site:
 
1% THD 6.8v RMS with 300Ω (154mW)
1% THD 6.8v RMS with 33Ω (1.4w)
 
So that 1.4 watts into 33 ohms.
 
If we take 1.4watts X (33ohms/200omhs) we get 0.231 watts into the LCD4.
 
I found the two to pair just fine in practice, however. 
 
Dec 12, 2016 at 3:48 PM Post #6,080 of 25,747
"The abyss is an easy load to drive with an impedance of 46 ohms, so there is no way Dave will run out of current - so you can run Dave at +4dB and the output from Dave will be linear. So assuming you are not running above +4dB, there is plenty of drive in voltage and current available. "

Current!!!
 
Dec 12, 2016 at 4:13 PM Post #6,082 of 25,747
Not my statement, but Rob Watts...
Not my observation but house specifications of the LCD4...
 
Dec 12, 2016 at 4:21 PM Post #6,083 of 25,747
I'm not trying to argue with you...  Your post made no mention of it being quoted.  You simply said:
 
"OPTIMAL POWER 1 - 4W [into the lcd4]
Do the Dave provide this optimal power? I think so..."

 
I just pointed out that based on wattage, no the DAVE falls short.  What you stated I found a little misleading.  I feel it insinuates that DAVE can output 1-4 watts into the LCD4, which is can't.  
That's all.
 
As I said, I didn't mean to step on any toes or get anyone upset.
 
Dec 12, 2016 at 4:41 PM Post #6,084 of 25,747
"OPTIMAL POWER 1 - 4W [into the lcd4] Do the Dave provide this optimal power? I think so..."
 
I just pointed out that based on wattage, no the DAVE falls short.  What you stated I found a little misleading.  I feel it insinuates that DAVE can output 1-4 watts into the LCD4, which is can't.

 
The "optimal power" statement is also misleading because at 97 dB/mW @ 200 ohms the LCD-4 only uses 20 mW to reach 110 dB, 63 mW for 115 db, and 200 mW for 120 dB.
 
Dec 12, 2016 at 4:42 PM Post #6,085 of 25,747
I find the discussions about Dave vs Dave with an amp to be among the most interesting I have read...I have both the Dave and the Moon 430 and to date the most perplexing thing to me has been whether or not to use the 430 along with the Dave when I listen to my LCD-4's...yes,I know it is all about how it sounds and that should be the only thing I consider but sadly I find myself going back and forth and one day thinking straight from the Dave sounds better and the next day I find the 430 with the LCD-4 to be better....

I believe that binaural recordings played through headphones are a great way to quantify a difference between two systems: transparency results in "life sized" rendering of the recorded performance. So I think it's possible to compare two systems using the difference in the way two systems render the size of the space and the distances to the musicians, and the feeling that the performers are present and that they seem to be full size.


[VIDEO]https://www.youtube.com/watch?v=itLxXeyM2aM[/VIDEO]


I'm interested in whether you find a difference between DAVE + LCD-4 and DAVE + Moon 430 + LCD-4. Does one of these two setups sound "bigger" than the other?

Similar for people who have Abyss and the choice of an amplifier or straight from DAVE. Does the sense of scale in a binaural recording differ in these two setups?

I'm also interested in what people find with different headphones when listening to binaural. Does a headphone with a reputation for having a "small" soundstage, such as Focal Utopia, sound "small" compared to headphones that have a "big" soundstage? I suspect Utopia won't sound "small" compared to other headphones when playing binaural.

So, in the end, I'm curious if binaural recordings, which are much better at sounding "transparent" on headphones, are a good way to compare headphone systems. I think so, but I only have my TT and 3 headphones (IEMs, HD 650 and HD 800).
 
Dec 12, 2016 at 4:58 PM Post #6,087 of 25,747
   
The "optimal power" statement is also misleading because at 97 dB/mW @ 200 ohms the LCD-4 only uses 20 mW to reach 110 dB, 63 mW for 115 db, and 200 mW for 120 dB.


So the Chord Mojo, Hugo and Hugo TT can drive the LCD-4 fine too also then. Unless you want to go listen at 120 db :p
 
Dec 12, 2016 at 5:30 PM Post #6,088 of 25,747
I have certainly found that different people listen to music at significantly different volume levels. This is almost regardless/independent of whether their system has distortions at high volumes. I found that my general music listening level is somewhere around 60-75dB which means that musical peaks can get to 85-95dB. Most audiophiles I know of generally listen to music at 10-15dB louder than I do. That means their average listening level can be somewhere up to 75-90dB and musical peaks can get to 100-110dB. And then my Chord dealer would once in a while have customers show up at his store and want to listen to music at 10dB louder than that so now we are talking about average volume levels around 85-100dB and with musical peaks reaching 120-130dB. They like to say they want to listen at concert level...
 
I suspect Chord DAVE has enough drive for most headphones for most people. But I think it really depends on the person...
 
With all that said, I've found I'm tempted to crank up my Mojo & DAVE because there is so little distortion I can keep on cranking it up without significant distortions. I'm really worried about my hearing. I have to remind myself to turn down the volume once in a while so I won't go deaf.
 
Dec 12, 2016 at 5:54 PM Post #6,089 of 25,747
In my opinion and according to my ears, if you got a very good transparent solid state amplifier, the only time you need to worry about the loss of transparency is with classical music. 
 
When listening to a violin, the transient response of the Chord Dave directly is more accurate . It's real instruments like violins that made me stop using an external amplifier with the Chord Dave. 
 
Dec 12, 2016 at 6:50 PM Post #6,090 of 25,747
So the Chord Mojo, Hugo and Hugo TT can drive the LCD-4 fine too also then. Unless you want to go listen at 120 db :p


Try to play the LCD-4 @ 120 db, with music on a Hugo or a TT :beers::grin:

What do you think will happen with the impedance when your headphones demands power of the amp to produce a 50hz signal @ 120 db? = impossible

200 Ohms are just a average value.

The automatic amp/hp calculator are not accurate unfortunately, because it is many more values that matter thug ( we are not listen to pink noise or sinus waves, we listen to music) , but it gives you a guidance direction, but far from accurate tool to relay on.

You need to measure the headphone on the fly with music signal to get a hint of how much power ( volt / current ) the hp's will drawn from the amp.
 

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