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Schiit Mjolnir headphone amplifier - Page 3

post #31 of 3329
Quote:
Originally Posted by purrin View Post

Mjolnir/Gungnir combination really kicks ass

 

photo.JPG

 

BTW, the HE400 (not pictured) also kicks ass

 

yeah, sorry I didn't see you there yesterday, I cannot attend today, might sneak back tomorrow. the HE400 also impressed me, and I took some cellphone pix of the Schiit set-up:

 

schiit.jpg  schiit2.jpg  schiit3.jpg

post #32 of 3329
Quote:

Originally Posted by SeaHawk View Post

 

But this is a generalization, no?  And single-ended relying on a common return brings us to the next point :)

 

It's only a generalization insofar as "balanced" amps use bridged outputs, which is the case for the vast majority that I'm aware of save for those using output transformers. Each single-ended "half" will have a given output impedance. Bridge two of those and you have an output impedance that's twice that of the single-ended halves.

 

Quote:

This is where the fun part starts. Assuming the common ground is on a perfect conductor we can virtualize the return back into the amplifier, but we're assuming this is a perfect electron sink and source of electrons simultaneously? I believe this would cause differential error/crosstalk between the channels and affect diaphragm control.

 

No idea where you've got this from.

 

Crosstalk is largely going to be by way of capacitive coupling between the left and right channels. Doesn't matter if the source is "balanced" or single-ended.

 

Quote:
I agree on the first point, however think there's a bit of fudge factor on the second, as I believe capacitance rather than resistance is the killer in headphone cords in single-ended systems and is a spec often overlooked in favor of low resistance claims (though, admittedly, very very small to the point it's at least inaudible if not unmeasurable unless you're trying hard to introduce the problem ;)

 

The capacitance of the cable is going to be the same whether it's driven from a "balanced" source or a single-ended source.

 

Quote:
The way I see it, if the diaphragms are being driven in opposite phases (yeah, not that common with lower frequencies that would exacerbate the effect and higher frequencies would be transient enough to minimize any effect), it would look like resistance was added or lowered to the other channel, not only affecting diaphragm control.  (Given that constructing said source material would be as useless as trying to reproduce perfect square waves, but dampening is the word for today.)

 

As far as the headphone's concerned, there are no "opposite phases." The headphone doesn't know balanced from a hole in the ground. It just sees the differential voltage applied to its terminals and behaves no differently whether it's driven from a "balanced" output or a single-ended output, save for whatever differences there may be in the output impedance between the two.

 

Quote:
In fact, you're kinda taking the wind out of the sails of balanced amps.. If none of this holds true, what's the benefit/why should we pay for this along with the trouble of recabling our phones?

 

I was just addressing your specific claims. I'll leave it to the makers of balanced amps to make their own case as to advantages.

 

But if nothing else, balanced outs, using four separate contacts for the connector does eliminate the common ground contact resistance of TRS plugs which can increase crosstalk.

 

se

post #33 of 3329

I was thinking along the lines of capacitance on the common return.. the circuit, not just the headphone cables.  I misused the term crosstalk - mea culpa - I'm still learning :)

 

As you say, the headphone diaphragms themselves don't care, unless there's a perfectly sealed chamber between them... Eh... I'll give up on the airhead joke while I'm still ahead...

 

They'll play what is fed to them, and my concern is that what's fed to them may be somehow degraded -- the two channels pull and push against each other through the common return -- I just find it hard to digest that this common return is Hand of God stable enough to prevent the two circuits from interfering with each other AT ALL.  I can see this logically possible in my head, but my id keeps going "but, but, but".  (I do enjoy the conversation).

 

Full disclosure: I'm likely misusing telco analogies since that was a field I've worked in for years. I know tip and ring -- sleeve is alien in the world I come from ;)  I've seen high capacitance on longer line runs and the use of load coils/inductors to offset that (you didn't really expect 56k with your modem, do you?).  I understand the importance of line impedance for termination to prevent echoes/ringing.  I have seen issues with bridge taps (basically extra wire on your circuit acting like a very good AM antenna and causing an impedance mismatch), and as often as not, results similar to a "single-ended" system by putting two circuits on three wires when there's a shortage of free copper pairs (the signal on each channel is entirely different, unlike most audio, and we can tell when this is done to a T1 by detecting errors in specific bit pattern tests).  With the latter, I've probably seen the worst-case scenarios of the three-wire/two-channel system, but can only describe the symptoms and the fix or work-around rather than the actual physics employed in the problem.

 

Two channels - three wires - we always fixed that with two pairs, and in my mind I desperately want to translate that into the audio world, or at the very least rationalize the purchase of new Schiit! ;)

 

If you haven't ignored me by now, what I'm grasping from you is that the biggest improvement technology-wise is in the connector... 

Seems that going with a whole different breed of amp just to get a new connector is a bit overboard?  Otherwise it just comes back to what product is engineered better (how boring is that?)


Edited by SeaHawk - 6/3/12 at 4:26am
post #34 of 3329
Quote:
Originally Posted by SeaHawk View Post

I was thinking along the lines of capacitance on the common return.. the circuit, not just the headphone cables.  I misused the term crosstalk - mea culpa - I'm still learning :)

 

As you say, the headphone diaphragms themselves don't care, unless there's a perfectly sealed chamber between them... Eh... I'll give up on the airhead joke while I'm still ahead...

 

They'll play what is fed to them, and my concern is that what's fed to them may be somehow degraded -- the two channels pull and push against each other through the common return -- I just find it hard to digest that this common return is Hand of God stable enough to prevent the two circuits from interfering with each other AT ALL.  I can see this logically possible in my head, but my id keeps going "but, but, but".  (I do enjoy the conversation).

 

Full disclosure: I'm likely misusing telco analogies since that was a field I've worked in for years. I know tip and ring -- sleeve is alien in the world I come from ;)  I've seen high capacitance on longer line runs and the use of load coils/inductors to offset that (you didn't really expect 56k with your modem, do you?).  I understand the importance of line impedance for termination to prevent echoes/ringing.  I have seen issues with bridge taps (basically extra wire on your circuit acting like a very good AM antenna and causing an impedance mismatch), and as often as not, results similar to a "single-ended" system by putting two circuits on three wires when there's a shortage of free copper pairs (the signal on each channel is entirely different, unlike most audio, and we can tell when this is done to a T1 by detecting errors in specific bit pattern tests).  With the latter, I've probably seen the worst-case scenarios of the three-wire/two-channel system, but can only describe the symptoms and the fix or work-around rather than the actual physics employed in the problem.

 

Two channels - three wires - we always fixed that with two pairs, and in my mind I desperately want to translate that into the audio world, or at the very least rationalize the purchase of new Schiit! ;)

 

If you haven't ignored me by now, what I'm grasping from you is that the biggest improvement technology-wise is in the connector... 

Seems that going with a whole different breed of amp just to get a new connector is a bit overboard?  Otherwise it just comes back to what product is engineered better (how boring is that?)

Hey, I used to work in Telco myself, but I was in the power distribution end.

A headphone circuit is a very short, low frequency line so we are not concerned with terminating the line impedance properly, the wavelengths are too long, the cables are too short, so echoes and ringing are not an issue like they are in RF.

Analog audio is low frequency, long wavelength information when compared to a T1 line.
In a good headphone cable (and amp) the resistance, inductance and capacitance of the cable are low enough to be irrelevant.
In addition, in a balanced line driver i.e. like the Mjolnir, since there are now two amps (or at least two output stages) driving each 'phone, we now have twice as much distortion and noise, but it is probably low enough to be academic.
Keep in mind in a balanced line driver both outputs are called upon to to source and sink current.
In single ended the active output and the ground are called upon to source and sink current.
In a well engineered single ended head amp, the common ground should not be an issue.


I would agree with your statement about the improved connector!
And I would also agree with your statement that it also come down to which amp is engineered better!  So your rationalization comes down to the Mjolnir is a better amp design (when used single ended) with a better connector.

I have nothing against balanced power amps and headphone amps, I use a balanced SS power amp myself, but that probably has more to do with my liking the sound signature of Pass Labs.

post #35 of 3329

What Chris J said.

 

se

post #36 of 3329

Appreciate the feedback, fellas!  I'll be quiet now for a while and try to listen instead... beyersmile.png


Edited by SeaHawk - 6/3/12 at 12:38pm
post #37 of 3329

In regard to this discussion, I just want to mention the Mjolnir's topology. In this case, we're not talking about "bridged" or "double output stages". I have yet to understand it myself, but do google "circlotron" or "cross-shunt push-pull". There is a real difference here, and what has been said about output impedance, distortion, noise and the like might not apply the same way as we're used to. It isn't even possible to use the Mjolnir single-ended, so it is not exactly a good platform for discussion of balanced versus single-ended.

post #38 of 3329

The Mjolnir sounds promising! Keep those impressions coming!

post #39 of 3329
Quote:
Originally Posted by O8h7w View Post

In regard to this discussion, I just want to mention the Mjolnir's topology. In this case, we're not talking about "bridged" or "double output stages". I have yet to understand it myself, but do google "circlotron" or "cross-shunt push-pull". There is a real difference here, and what has been said about output impedance, distortion, noise and the like might not apply the same way as we're used to. It isn't even possible to use the Mjolnir single-ended, so it is not exactly a good platform for discussion of balanced versus single-ended.

 

Oye!frown.gif

Yer right, ya can't run it single ended output!

It looks very unusual, so I will assume..................

Apparently it was reverse engineered by scientists at Roswell, New Mexico from alien technology.tongue_smile.gif

post #40 of 3329
Quote:
Originally Posted by Chris J View Post

 

Oye!frown.gif

Yer right, ya can't run it single ended output!

It looks very unusual, so I will assume..................

Apparently it was reverse engineered by scientists at Roswell, New Mexico from alien technology.tongue_smile.gif

 

tongue_smile.gif

This reminded me of the design of their statement DAC. How? Well... semi-quoting Jason:

 

Quote: Jason Stoddard
Quote: Anaxilus
I expect a DAC designed by thinking machines on Planet Ix.

 

Mike Moffat sez,

"I resemble that remark!"

...

 

Hmm... there certainly seems to be some speculation on this Schiit being from outer space. Ì wonder if there is a connection to the connection between Jason and sci-fi? biggrin.gif

post #41 of 3329

I heard that the biggest drawback of balanced amp is that every parts in the circuits has to be doubled and should be kept in strict tolerance with each other which as we know in all electronic matters can suffer some deviance over time and condition of use.

post #42 of 3329

Cheers purrin. Sounds promising - dammit!

post #43 of 3329
Quote:
Originally Posted by telecaster View Post

I heard that the biggest drawback of balanced amp is that every parts in the circuits has to be doubled and should be kept in strict tolerance with each other which as we know in all electronic matters can suffer some deviance over time and condition of use.

 

Yeah, I agree it's true.

 

But in this topology, looks like the big $$$$ penalty in the MoJo's Cyclotron circuitry is the additional power supply.

 

Yes, it's true, I hearby christen it the MoJo.

post #44 of 3329

Wouldn't it be Joni? :p  Open order page please.

post #45 of 3329
Quote:
Originally Posted by Solude View Post

Wouldn't it be Joni? :p  Open order page please.

 

Maybe, but you have to admit that MoJo sounds funnier!tongue_smile.gif

 

Especially with the Psycho-Tron circuitry!

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