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head injury said:

He didn't mean that sort of sensitivity. He meant that the driver design might be more susceptible to the issue.
 
There was no need to be so hostile.

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Who's being hostile?  The specs are the specs.  As I said previously, this is not rocket science.  I'm not being hostile, I'm simply calling for an end to silly speculation.  Let's stick to the known facts.
 

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kwkarth said:

Who's being hostile?  The specs are the specs.  As I said previously, this is not rocket science.  I'm not being hostile, I'm simply calling for an end to silly speculation.  Let's stick to the known facts.
 

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The problem is the most factual thing we have, in this 4 pages of posts, is the video. There's no denying what we can all see with our own eyes.
 
We're rather weak on other verified facts. For a driver to displace that far, and that hard, it's hard to imagine it's doing so with only 0.15 volts as Schiit has implied (although the transient voltage might be around double that into the higher into 60-ish ohms of the K 702). 0.3 volts is slightly more believable but that's still hard for me to swallow.
 
To put some simple (factual) math to this: The K 702 hits 105 dB with 1 volt RMS which is 1.4 V peak. Most people consider music loud with peaks hitting 110 dB which would require 2.5 volts peak with the K 702.
 
So listening to music on the K 702 it's entirely reasonable to have peaks of 2.5 volts, yet Schiit is claiming a transient of only 0.15 - 0.3 volts or so. For a driver that's operating well within its linear range (nowhere close to bottoming out) at 2.5 volts, it's really hard to believe a tiny fraction of that is enough to bottom it out as hard as we can all see in the video.
 

Quote:

nwavguy said:

The problem is the most factual thing we have, in this 4 pages of posts, is the video. There's no denying what we can all see with our own eyes.
 
We're rather weak on other verified facts. For a driver to displace that far, and that hard, it's hard to imagine it's doing so with only 0.15 volts as Schiit has implied (although the transient voltage might be around double that into the higher into 60-ish ohms of the K 702). 0.3 volts is slightly more believable but that's still hard for me to swallow.
 
To put some simple (factual) math to this: The K 702 hits 105 dB with 1 volt RMS which is 1.4 V peak. Most people consider music loud with peaks hitting 110 dB which would require 2.5 volts peak with the K 702.
 
So listening to music on the K 702 it's entirely reasonable to have peaks of 2.5 volts, yet Schiit is claiming a transient of only 0.15 - 0.3 volts or so. For a driver that's operating well within its linear range (nowhere close to bottoming out) at 2.5 volts, it's really hard to believe a tiny fraction of that is enough to bottom it out as hard as we can all see in the video.

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I agree with the concept of what you're saying, however propagation of hysteria never helps anything.  I'll do some measurements tomorrow and post them.
 
 

 

And by the way, if there is anything wrong with the Asgard in question, Schiit will of course replace it - our customer service has been well spoken of in these forums.  That's it and all I have to say about that.  I am in the throes of the final tweaks on the Schiit Bifrost.  As a card carrying TWAD (Tree Worshipping Analog Druid) I am proud to say that this unit sonically rocks!!
MM

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baldr said:

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 I have never been involved with debates or controversy on this or any other forum. I am now compelled to comment on several asseverations made by nwavguy re Schiit's design philosophies in general and the Asgard in particular. He(she?) poses contentiously, citing his “professional engineering opinion”. Hiding in the cloak of anonymity, his/her actions are proper to those of a coward and a bully. Who is he/she? What is his/her agenda? What are his/her credentials? <marketing stuff for Schiit and its employees removed>

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I don't have any problem with people who want to buy single ended amps, tube amps, etc. That's their business. And I don't have a problem with companies that sell such gear. But when manufactures don't own up to problems with their products, misrepresent the objective performance of their products, start talking in fake pseudoscience, etc. I think someone should point out the facts. At the moment I can't prove that's the case with Schiit, but I have to say the evidence is pointing in that direction so far with respect to the power off transient from the Asgard.
 
You can rave all day long about how amazing Schiit products sound and I won't say a word. That's a purely subjective thing. But when Jason claims a small fraction of a volt is severely bottoming out a headphone driver designed for 10+ times that voltage, I think it's fair to point out that doesn't seem to add up. The laws of electromagnetic force dictate how much current is required to do what we can all see in the video.
 
If you haven't read it, I wrote and article about the Subjective vs Objective debate. It's far too lengthy to try and reproduce here. But the bottom line is I try to stick to objective information whenever possible. The article explains the anonymity. It also provides examples of highly subjective audiophiles trying to shoot the objective messenger rather than admit to the real performance issues with the product in question. Many, for example, have attempted to discredit Meyer and Moran for their AES published high resolution audio study just like you're trying to discredit me. You imply I'm a coward, bully, etc, but you fail to provide any further factual evidence regarding the real issue here (the transient).
 
As for my technical credentials, I think if you take the time to look at all of my measurements, technical articles, etc. you'll find my engineering knowledge is fairly solid. Anyone is free to challenge any of my technical statements. I'm not perfect, I make mistakes like the next guy, and I'm happy to admit when I'm wrong and fix my errors. Which is more than I can say for some of the audiophile designers and manufactures I've encountered.

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nwavguy said:

I don't have any problem with people who want to buy single ended amps, tube amps, etc. That's their business. And I don't have a problem with companies that sell such gear. But when manufactures don't own up to problems with their products, misrepresent the objective performance of their products, start talking in fake pseudoscience, etc. I think someone should point out the facts. At the moment I can't prove that's the case with Schiit, but I have to say the evidence is pointing in that direction so far with respect to the power off transient from the Asgard.
 
You can rave all day long about how amazing Schiit products sound and I won't say a word. That's a purely subjective thing. But when Jason claims a small fraction of a volt is severely bottoming out a headphone driver designed for 10+ times that voltage, I think it's fair to point out that doesn't seem to add up. The laws of electromagnetic force dictate how much current is required to do what we can all see in the video.
 
If you haven't read it, I wrote and article about the Subjective vs Objective debate. It's far too lengthy to try and reproduce here. But the bottom line is I try to stick to objective information whenever possible. The article explains the anonymity. It also provides examples of highly subjective audiophiles trying to shoot the objective messenger rather than admit to the real performance issues with the product in question. Many, for example, have attempted to discredit Meyer and Moran for their AES published high resolution audio study just like you're trying to discredit me. You imply I'm a coward, bully, etc, but you fail to provide any further factual evidence regarding the real issue here (the transient).
 
As for my technical credentials, I think if you take the time to look at all of my measurements, technical articles, etc. you'll find my engineering knowledge is fairly solid. Anyone is free to challenge any of my technical statements. I'm not perfect, I make mistakes like the next guy, and I'm happy to admit when I'm wrong and fix my errors. Which is more than I can say for some of the audiophile designers and manufactures I've encountered.

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For someone who claims to stick to the objective, you're not doing a very good job.  Of all the outrageous statements you've made in this thread, which ones have you objective evidence to validate?  Have you ever had your hands on an Asgard amplifier? No?  Why then, are you here?  I mean really, in the interest of head-fi'ers everywhere, what is your involvement with these amplifiers?  You have not provided a single shred of evidence to support any of the claims you've made in this thread.  As far as the driver "bottoming" out "severely" as you put it, It didn't look like that to me.  I heard no sound of the voice coil former hitting the back of the magnet structure.  As a matter of fact, it seemed to move rather slowly over the space of about a quarter of a second.  that should be pretty easy to capture/measure.  I'll post my findings tomorrow.  Then we can talk about objective measurements rather than wild groundless speculation.
 
 

nwavguy: What did you say your name was again?

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kwkarth said:

For someone who claims to stick to the objective, you're not doing a very good job.  Of all the outrageous statements you've made in this thread, which ones have you objective evidence to validate?  Have you ever had your hands on an Asgard amplifier? No?  Why then, are you here?  I mean really, in the interest of head-fi'ers everywhere, what is your involvement with these amplifiers?  You have not provided a single shred of evidence to support any of the claims you've made in this thread.  As far as the driver "bottoming" out "severely" as you put it, It didn't look like that to me.  I heard no sound of the voice coil former hitting the back of the magnet structure.  As a matter of fact, it seemed to move rather slowly over the space of about a quarter of a second.  that should be pretty easy to capture/measure.  I'll post my findings tomorrow.  Then we can talk about objective measurements rather than wild groundless speculation.
 
 

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The amount of voltage the AKG K 702 driver is designed to handle is very objective. It should be able to easily handle 2.5+ volts without breaking a sweat. So how can roughly 1/10th that amount drive it so hard the surround distorts and it makes weird noises? That's very objective.
 
The speed of the "transient" is related to the large filter capacitors in the power supply of the Asgard slowly discharging after it's turned off. The slower the transient the WORSE this problem is. So you have that exactly backwards. Fast transients just create a quick "click". Slow ones, like this one, seriously stress the headphone driver.
 
Many drivers are limited by their suspension, not the voice coil hitting bottom. I use "bottoming out" as a general description of the driver reaching its limits of travel. In this case, the poor suspension is being stressed to the limits.
 
I sincerely hope kwkarth, as both an owner of a Schiit amp, and an adminstrator here where Schiit is a paying sponsor, you'll accurately report your measurements? I'm not sure how you plan to measure to the transient? As I said, the only proper way to do it is with a digital scope with response down to DC. A PC sound card can't do that. And most DMMs will be hard pressed to capture the true peak of the transient as their update rate is rather slow.
 
I will also be trying to get my hands on an Asgard so I can measure it as well. The more objective data the better. The best measurements are the ones that are easily verified by others.
 

Mr nwavguy,
I don't want this to be too confrontational, but there are a number of statements that you made that were quite negative and yet without foundation.  Why would an engineer such as yourself do such a thing?
 
Quote:

nwavguy said:

• My professional engineering opinion, having done both amplifier and speaker development, is this is potentially harmful and a serious flaw with the Asgard.
• The Schiit amps are clearly not designed for good objective performance. And when designers have other goals in mind there are often some serious side effects. NuForce doesn't seem to care the uDac-2 has serious channel balance problems for example. They claim that bad channel balance was necessary for the best sound at the price.
• The Asgard may have been designed with similarly misguided, or sloppy, priorities.
• I hate to say this but your AKGs may already have been damaged and it's just not obvious by listening to them.The material properties of drivers are critical to their performance. For example, when I did speaker development, we had a high-end tweeter dome that was accidentally "dented" in. It was a replaceable dome/voice coil assembly so I took the tweeter apart and carefully popped the "dent" out. The dome looked perfect. But the tweeter then measured completely differently and sounded worse. It had a new peak and a big dip in the response that were not there before the dent. We ordered a new dome/voice coil and it again matched the original measurements.

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Do you have any objective evidence for these statements above?
 
How about the statements below?
Quote:

nwavguy said:

• I would say it could, in theory, damage most any headhone but higher impedance ones are likely less at risk. The other issue with DC, even if it doesn't physically trash the diaphragm, is causing permanent magnetic changes (damage). DC currents tend to magnetize ferrous metals, and I'm not an expert on the subject, but some smart people have said certain headphone designs are susceptible to that sort of damage.
• I'm guessing here, but the Asgard seems like essentially a Nelson Pass-ish single ended design. If it really draws even close to 35 watts of power it has a big power supply, big heatsink(s), and big output devices. Just those things, combined with the complex to manufacture enclosure, cost some serious cash--especially to build it in the USA. That probably didn't leave much money left over for say an output relay and associated circuitry to protect the headphones. So, sort of like with NuForce and the uDAC-2, Schiit may have cut some corners to keep it under $250.
• But, in my opinion, potentially damaging customer's headphones is not a good corner to cut. And, to go a step further, all that money spent on the relatively massive single ended design is also a waste unless you're after tube-like euphonic distortion. I do give them points, however, for great looking products and a very slick website (even if it is 95% marketing hype).
• It would be interesting to get the Asgard on the test bench. I'm fairly sure it would measure much worse than a $39 Cmoy in most aspects. That would probably just turn into yet another objective vs subjective debate. The Asgard has enough distortion, and possibly a high enough output impedance, that it may well be easy enough to pick out in a blind test against a more accurate amp. So it would come down to which one you like better--accurate or distorted.

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How do you back these charges up?
 
And there's more below;
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nwavguy said:

• Thanks for the added info. I agree output relays are not all that common (although the $129 FiiO E9 has one). But the reason most amps don't need them is most amps don't try to destroy your headphone diaphragms when you turn them off like the Asgard apparently does. That's not what I'd call a "relatively minor transient".

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nwavguy said:

• I'm not trying to trash anything just offer an engineer's perspective on a question many are obviously concerned about. I've praised far more products than I've "trashed". When you see what's happening in the video, I think it's fair to be concerned about the health of the headphones. I didn't start this thread, and I'm not the first person to be concerned.
   
• Just blindly taking Schiit's word this isn't a problem seems foolish to me when expensive headphones are potentially at stake. I think those spending money on expensive headphones and amps should value independent information rather than try to marginalize it or accuse the person of having some hidden agenda. It should be obvious Jason at Schiit is the one with the biggest agenda and the largest bias regarding this issue, followed by those who own Schiit amps. There's not much in this for me except being attacked by the Schiit fan club.
   
• It's certainly possible the transient is harmless to most headphones and the AKGs are somehow unusually sensitive. But, regardless, it's something to take seriously. 

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Why should we take your word blindly, particularly when you have NO fact to substantiate your accusations?
 
 

@kwkarth, I think you're scraping the bottom of the subjective barrel here. Go ahead and try to misquote me, take my statements out of context, etc. In the end, it all comes down to the Schiit Asgard. If the transient on power down is much greater than the 0.15 volts claimed by Schiit, then I rest me case. If all Asgard amps are under around 0.15 volts when you power them down, then I'll readily agree Schiit was correct. It's pretty simple.
 
I have a few leads on testing an Asgard. So it really comes down to the measurements. Good measurements are easily verifiable by others. The Ford Mustang GT either does 0-60 in the claimed 5.6 seconds or it doesn't. And the the nasty transient when you power down a Schiit Asgaurd is either the claimed few tenths of a volt or much worse. This isn't rocket science. The truth will be revealed in the end.
 
 

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Originally Posted by kwkarth /img/forum/go_quote.gif
 
I own the K701 and the K501 and they both have been working great with both the Asgard and the Lyr.

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Great, since you know your Asgard is in working order can I propose a test?
 
Hook in the K501, take off the pads.  Turn the power on, give it three seconds or so, turn the power off.  Does the driver crumple in any way?
 
Next, do the same for the K701.  Does it crumple in any way?
 
If the K501 didn't but the K701 does, then the issues is the Varimotion has problems with the turn off transient.  If they both do, then the transient may be too high for AKG headphones -- or possibly too high in general.  If neither do, then it was my Asgard in question.  Simple yes?
 
Also, you mentioned measuring your Asgard.  If you do so make sure to hook a ~30 ohm dummy load to it.
 
 
All I can say is this thread took a turn for the inane.
 

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jason stoddard said:

Hey all,
 
I just saw this thread here. Shike, sorry you feel like you have to send the amp back. All I can say is this:
 
1. On Asgard, a mild turn-off transient is normal, but we'll check your amp when it comes back to make sure it isn't excessive. 
2. We're getting near 1000 Asgards shipped between 115V and 230V models, and we've never heard of headphone failure caused by Asgard, including IEMs.
3. Our standard final listening-test HD650s have gone through thousands of on-off cycles on all models, and they've never had a problem.
4. We absolutely do design for excellent objective performance, as well as subjective performance. We've had many, many rave reviews on Asgard, including from engineers who have measured the performance of the amp. 
5. Between Mike and I, we have designed and shipped dozens of audio products, ranging from tube preamps to surround sound decoders, and shipped well over 100,000 units of said products over the last 30 years, to both critical and objective acclaim. This ain't our first rodeo. If you have any engineering questions about our products, I invite you to discuss them directly with myself and Mike.
 
All the best,
Jason
 

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Hi Jason. I do have an engineering question about the Asgard. Is a schematic available? They're downloadable for my Adcoms, Brystons, and Haflers. Some headphone amp manufacturers even post theirs here (e.g., FiiO E9 block diagram). But I fully understand if you don't want to do that. There's a picture of the Asgard's internals on your profile, and it's pretty spare. Judging from the pic and the description--single ended, non-inverting--I might guess that it has a differential pair, and then a follower. Even without a schematic, one could start wondering about details like the rail voltage, the size of the coupling cap, and the voltage across it. Also how is the power switch connected? As mentioned earlier, the amp behaves differently when the power cord is unplugged.
 
Maybe this would be better asked in the amps forum, in the main product thread. But maybe only readers of the Sound Science forum would be interested in the answer. Perhaps in a different thread?
 
 

Quote:

nwavguy said:

@kwkarth, I think you're scraping the bottom of the subjective barrel here. Go ahead and try to misquote me, take my statements out of context, etc. In the end, it all comes down to the Schiit Asgard. If the transient on power down is much greater than the 0.15 volts claimed by Schiit, then I rest me case. If all Asgard amps are under around 0.15 volts when you power them down, then I'll readily agree Schiit was correct. It's pretty simple.
 
I have a few leads on testing an Asgard. So it really comes down to the measurements. Good measurements are easily verifiable by others. The Ford Mustang GT either does 0-60 in the claimed 5.6 seconds or it doesn't. And the the nasty transient when you power down a Schiit Asgaurd is either the claimed few tenths of a volt or much worse. This isn't rocket science. The truth will be revealed in the end.

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I posted exact cut and paste copies of what you posted and you have failed to respond.  You seem to have an axe to grind.  Why did you make those charges and then fail to back them up?
 

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shike said:

Great, since you know your Asgard is in working order can I propose a test?
 
Hook in the K501, take off the pads.  Turn the power on, give it three seconds or so, turn the power off.  Does the driver crumple in any way?
 
Next, do the same for the K701.  Does it crumple in any way?
 
If the K501 didn't but the K701 does, then the issues is the Varimotion has problems with the turn off transient.  If they both do, then the transient may be too high for AKG headphones -- or possibly too high in general.  If neither do, then it was my Asgard in question.  Simple yes?
 
Also, you mentioned measuring your Asgard.  If you do so make sure to hook a ~30 ohm dummy load to it.
 
 
All I can say is this thread took a turn for the inane.
 

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Yes, I was planning to do that test as well.