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Schiit Mjolnir headphone amplifier - Page 124

post #1846 of 3169

Thor's Hammer have arrived...More details later..biggrin.gif

 

 

For now i'm HAPPY...

post #1847 of 3169
Quote:
Originally Posted by keph View Post

Thor's Hammer have arrived...More details later..biggrin.gif

 

 

For now i'm HAPPY...

 

Congrats.  I love my Mjolnir...cept the fact it doesn't play nice with most stock cables (most are non-XLR) and I own a lot of headphones...recabling adds up quickly.

post #1848 of 3169
Quote:
Originally Posted by brunk View Post

If you're interested in purchasing a Mjolnir and using the Pre, I have one piece of cautionary advice. Do not use it with Emotiva amps. The gain of the Mjolnir+Emotiva amps leaves you about 25% of play with the volume knob before you start to shake your house lol. Its way too loud past the 9 O'clock position. You just barely touch the knob and the volume will very noticeably increase. 

I haven't had the problems noted above. I'm using the MJ to drive an Emotiva XPA-2 connected to speakers with a 91 dB efficiency. Yes, the knob on the MJ doesn't get much above the 9 o'clock position. But the channel tracking and control work just fine for me. 

post #1849 of 3169
Quote:
Originally Posted by brunk View Post

Haha yep. Another thing too that I'm noticing and it's quite troubling, is channel imbalancing below the 7-8 o'clock position. The majority of sound comes out the right speaker, ruining the imaging :( Does anyone else have this issue, is it a defect or documented? With the volume that low however, it's like midnight listening level, but still bothersome.

 

Channel imbalance at low levels is (from my understanding) a very common thing with analog volume controls and just how they work. Both the cmoy I built and my Asgard have the same 'issue'

post #1850 of 3169
Quote:
Originally Posted by brunk View Post


Haha yep. Another thing too that I'm noticing and it's quite troubling, is channel imbalancing below the 7-8 o'clock position. The majority of sound comes out the right speaker, ruining the imaging :( Does anyone else have this issue, is it a defect or documented? With the volume that low however, it's like midnight listening level, but still bothersome.

 

I have the same issue, through the headphone out though. Resorting to software volume control to resolve.

post #1851 of 3169

A balanced amplifier doesn't necessarily deliver higher power (although that's usually true, especially for designs running on limited voltage - like portables). Likewise, crosstalk may be lower, but that isn't necessarily true either.

 

There is are, however, other benefits.

 

With a real balanced amplifier, the output is the difference between two similar amplifier channels.

Therefore, any distortion that is produced equally by both channels (as a result of circuit design) is largely cancelled out.

This results in lower inherent distortion overall - which always good, but is especially important with low-feedback or no-feedback designs

 

Keith

 

Quote:
Originally Posted by IEMCrazy View Post

 

CMRR obviously, reduced crosstalk, though crosstalk can also be reduced just by using an XLR connector instead of a TRS connector on an SE amp, there's additional gains by going balanced.  As paradox said, power, for headphones that need it, longer cable runs are possible, and typically better SNR due to higher voltage transmission of the signal (though that's by no means absolute.)

 

 

Greater resolution just by being balanced?  confused.gif  In the sense of the above being applied, the result would be the ability to perceive better resolution, sure, but isn't that as much a simplification as the "poop analysis" of HD800? tongue_smile.gif

post #1852 of 3169

Channel imbalance is indeed a function of how analog potentiometers are made. Low cost potentiometers are very bad, and even expensive ones tend to lose channel tracking at lower settings (more expensive ones have better tracking, and maintain tracking to lower levels, but even expensive ones have limitations). Stepped attenuators avoid this problem for the most part, but you either end up with limited steps, or a very expensive and physically large control, or both. Stepped TRANSFORMERS are expensive, and you have all the distortions and other issues that come with transformers.

 

The best "external" compromise is to use an analog potentiometer and a "gain" switch - so the potentiometer can always be used out in the middle of its travel instead of down near the bottom.

 

Digitally controlled analog ladder networks work well (they have a stepped analog attenuator with a whole bunch of steps in an IC; the steps are switched by computer-controlled analog switches).

 

Next down the line would be a good digital volume control with plenty of bits and dithering (24 bits with dither is pretty good if you don't turn it down too far.)

 

Least and worst is a "plain old non-dithered 16 bit digital volume control" - which is, unfortunately, what most computer software and many lower-end DACs use. That type of control simply divides the number down to make it smaller BEFORE doing the D/A conversion, so the number of bits of resolution is reduced when you turn it down. (They're actually not too bad at higher settings, but lower settings should be avoided.) That's what you get when you use the "Windows volume control" by itself - and is why you should NOT use it.

 

Keith

 

Quote:
Originally Posted by Defiant00 View Post

 

Channel imbalance at low levels is (from my understanding) a very common thing with analog volume controls and just how they work. Both the cmoy I built and my Asgard have the same 'issue'

post #1853 of 3169

Has anyone tried the Mjolnir with a pair of Grados? I really like the sound of rock coming out of this amp and am very interested in the Grado/Mjolnir synergy...
 

post #1854 of 3169
Quote:
Originally Posted by kLevkoff View Post

A balanced amplifier doesn't necessarily deliver higher power (although that's usually true, especially for designs running on limited voltage - like portables). Likewise, crosstalk may be lower, but that isn't necessarily true either.

 

There is are, however, other benefits.

 

With a real balanced amplifier, the output is the difference between two similar amplifier channels.

Therefore, any distortion that is produced equally by both channels (as a result of circuit design) is largely cancelled out.

This results in lower inherent distortion overall - which always good, but is especially important with low-feedback or no-feedback designs

 

Keith

 

True. But we are talking about the Mjolnir. Which applies all of these attributes.

 

And yadda yadda, it comes down to implementation, etc. The Mjolnir does it right.

post #1855 of 3169

Thanks for the knowledge bombs Keith.

post #1856 of 3169

Running the Mjölnir without anything plugged into the inputs will cause something bad to happen, right?

post #1857 of 3169
Quote:
Originally Posted by mackat View Post

Running the Mjölnir without anything plugged into the inputs will cause something bad to happen, right?

http://www.youtube.com/watch?v=H1sS1TmXF38

post #1858 of 3169

Is that serious, or a joke? My apologies, I have a hard time telling between them! :D

post #1859 of 3169
Quote:
Originally Posted by mackat View Post

Is that serious, or a joke? My apologies, I have a hard time telling between them! :D

 

Try it.

 

Really though it won't matter.  The real question is "why?".

post #1860 of 3169
Quote:
Originally Posted by mackat View Post

Running the Mjölnir without anything plugged into the inputs will cause something bad to happen, right?

 

Where'd you get this idea? Mjolnir doesn't need inputs to be stable, or outputs not to burn up, you don't have to plug and unplug headphones, nor do you have to twirl by the light of the full moon with a dead chicken in your arms in order to appease the Circlotron God in order to have it run right. In terms of operational oddities, it's a totally boring amp.

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