[wuwhere]

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That's interesting. I wouldn't equate hiss with distortion, but it seems like there is a bit of a noise floor that rises with more efficient headphones.
 
Perhaps Mr. Guttenberg could chime in at some point too

!

Interesting indeed, from headfonia review of DS, hiss was never mentioned by anyone who listened to it.

 

[kevin gilmore]

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edit:
oh, and the hiss is a constant.
it also does not change based on the volume level of the dark star.
doesn't get louder when the dark star is turned up.
 
 
 

The TI datasheet
http://www.ti.com/lit/ds/symlink/opa541.pdf
 
page 4 bottom left, noise density vs frequency.
You should be able to calculate the levels of noise at the frequency of your choosing.
This is why the noise level is constant, the input amplifier has a noise level at
least 20db better than the output amplifier.
 
page 4 bottom right, THD + NOISE with respect to power levels.
Yes the distortion rises as the power level goes down.
 
Translation:  This amp likes to be played loud. VERY LOUD
Translation:   This amp is NOT designed for sensitive IEM's
 

 

[musicman59]

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Anyone knows or has experience -  how it compares to Head-Direct's EF-6?
 
Thanks
 
PS: Nice review ...

 
Yesterday we had our Detroit Metro meet at Headfi.com headquarters. Jude had a EF-6 there to demo and I brought my Dark Star.
The EF-6 is a good looking amp, fairly big and heavy with a lot of heat sinks to dissipate the heat of its class A operation of 5 watts.



 
I was needing to bring the volume knob in the EF-6 up to 12 O'clock to get my normal listening volume in the HE-6 while in the Dark Star is only at 10 O'clock. Also, IMO the sound of the EF-6 is not as dynamic, clean and refined as out of the Dark Star. Sure the price differential is substantial but I think the quality of the sound is also significant so it all depends of your budget and the value you put in getting the best possible sound. If you are in the $1,500 range surely the EF-6 is a great option but if you can extend yourself to the next level then the Dark Star is a sure bet IMO.
 
 

 

[El_Doug]

So both amps have too much gain for even one of the hardest-to-drive cans in existence, and thus are creating useless noise for no reason? 

 

[mulveling]

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and, by the way bcg27, knowing technicalities does not qualify one to comment on an amp they've never heard.
 
i don't go around in the beta 22 theads knocking that amp.
i'm sure it's a great amp.
 
but since you brought up THD, i'll illustrate something for you about the 2% figure.
 
2dB is the sound of someone rubbing the skin on their fingers together.
go ahead, try it.  it's awfully quiet.  try it in a noisy environment, and you won't hear  it.
 
100 dB is the sound of standing next to a car with its engine revving.
 
now stand next to a car with its engine revving, and rub your fingers together.
that is the sound of the distortion products of the dark star.
 
 

Here's a quick brush up on high school math:
2% distortion means that the power of the distortion signal divided by the power of the full signal is 0.02
By definition:
delta in decibels = 10 * log_base_10 (power factor) =>
10*log(0.02) = -16.99 dB
 
So the 2% distortion signal in your 100dB revved engine analogy would actually be at 83dB, not 2dB. THAT would be more like the sound of a vexed girlfriend/wife trying to get your attention to turn the damn thing off (at least, for the first couple tries). Note that many tube amps (not all) will have a similar levels of distortion, except that it tends to be more aesthetically pleasing than that of their solid-state counterparts. So back to your car analogy - a tube amp's distortion would be like a hot single babe going "hey hon, wanna take me for a ride?"
 
 

 

[sillysally]

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So the 2% distortion signal in your 100dB revved engine analogy would actually be at 83dB, not 2dB. THAT would be more like the sound of a vexed girlfriend/wife trying to get your attention to turn the damn thing off
 
<snip>
 

That's funny and sadly so true. That's why I embarked on the path I am on for my music and movie viewing, got tried of hearing about it. Now everybody is happy, and the wife actually encouraged me to get my latest Stax rig.
 
 

 

[Kremer930]

Could you provide some basis as to where this conclusion comes from?  Or have I just missed something here?
 
From my interpretation of what has been seen only the Dark Star has adequate gain.
 
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So both amps have too much gain for even one of the hardest-to-drive cans in existence, and thus are creating useless noise for no reason? 

 

 

[Syan25]

Yeah - I would imagine it has BAGS of gain....

 

[El_Doug]

Of course it has adequate gain - it has far far far far too much gain!  If even the HE-6 maxes out at 10 o'clock, then a lot of excess gain is contributing to the higher noise floor
 
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Could you provide some basis as to where this conclusion comes from?  Or have I just missed something here?
 
From my interpretation of what has been seen only the Dark Star has adequate gain.
 


 

 

 

[Frank I]

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So both amps have too much gain for even one of the hardest-to-drive cans in existence, and thus are creating useless noise for no reason? 

Unless you have heard either amp this post is  pointless.

 

[Steve Eddy]

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Unless you have heard either amp this post is  pointless.

Sort of reminds me of an old George Carlin bit about how to get out of jury duty. You tell them "I'd make a great juror! I can tell if someone's guilty or not just by lookin' at 'em!"

 
se
 
 
 
 

 

[musicman59]

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Of course it has adequate gain - it has far far far far too much gain!  If even the HE-6 maxes out at 10 o'clock, then a lot of excess gain is contributing to the higher noise floor
 


 

I never said that the HE-6 maxed out at 10 o'clock. I said that they reach my listening levels at 10 o'clock while the EF-6 had to go up to 12 o'clock.
That is different than maxing out the HE-6.
So for instance in my Woo WA5-LE I just go up to 9 o'clock to reach my lsitening level with the HD-800 then you think the WA5-LE has far far far too much gain too?
 
My whole point in my post was to say that IMO the EF-6 has less power than the DS and in additon the DS IMO has lower floor noise and cleaner sound too.
 
Please listen to both side by side and let us know what do you think of them.
 
 
 

 

[justin w.]

Quote:

I never said that the HE-6 maxed out at 10 o'clock. I said that they reach my listening levels at 10 o'clock while the EF-6 had to go up to 12 o'clock.
That is different than maxing out the HE-6.
So for instance in my Woo WA5-LE I just go up to 9 o'clock to reach my lsitening level with the HD-800 then you think the WA5-LE has far far far too much gain too?
 
 
 

Gain and power are not related
Position of the volume knob is also not related to gain or to power, as different volume controls have different attenuation curves
(I assume both amps were attached to the same source, or that's another variable)

 

[TheWuss]

Quote:

Here's a quick brush up on high school math:
2% distortion means that the power of the distortion signal divided by the power of the full signal is 0.02
By definition:
delta in decibels = 10 * log_base_10 (power factor) =>
10*log(0.02) = -16.99 dB
 

you can call it a brush up on high school math if you wish.  i can take the ribbing.
 
however, i'd call it "forgetting that decibels are a logarithmic unit of measurement".   a simple mistake that i'd like to pretend is made all the time, right? 

 
 

 

[choptalk]

Can anyone compare this to the LF using LCD2