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Old 28th September 2011, 07:33 PM   #41
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Originally Posted by ! View Post
IF nothing more comes out of this topic, realize that the goal is sound, NOT what your particular cans are like when they react, unless that was the stated goal. An amp should be neutral, not corrective of other component flaws.
This statement makes no sense at all. I wasn't aware that more noise and crosstalk was neutral. Nor was I aware that I should expect an amp to change the sound in any appreciable way aside from louder reproduction of the original signal.

The sure IEM's are used as a worst case scenario. You can't fault a measurement taken in the worst possible case. Almost anything in the real world is assured to be better. I am not going to pretend that any IEMs even require an amp. At that point, you are using the amp for blind EQ. No you most certainly don't build an amp for the way it sounds. You build one to power phones that can't be powered properly from the original source.

You can continue to claim that discrete components and a ground channel make an amp better, not worse, based on your hearing. I prefer to believe the measuring device who's sole purpose for existing, is to quantify noise and signal changes that the human ear/brain can't comprehend. Next you'll be telling us that the D-scope is telling lies because it hates AMB.

If anything comes from MY thread. I would like it to be objective. If your fanboyism continues to seep it's way into it, I will be forced to ask a moderator to step in.

Such a shame. This thread managed to stay totally objective for years.

Measures better = is better. End of discussion. Anything else is your human brain telling you lies.

Last edited by Rembrant; 28th September 2011 at 07:48 PM.
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Old 28th September 2011, 10:47 PM   #42
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^ You can in fact fault a measurement that is supposed to be representative of an amp in general but the test is contrived to show it at its worst.

Similarly, testing methodology could be changed to show other amps at their worst. We can fairly say that when testing isn't done with common values, the tester is either ignorant or has some objective other than representing typical use.

You wrote you build one to power phones that can't be powered properly but that's a bit ambiguous because often when they aren't "powered properly" the result is poor sound, not just lack of volume that the headamp adds with more than unity gain.

I am not a fanboy of AMB's, it was merely one example of a 3 channel amp where one person mentioned benefits of the 3rd channel. There are many people who have designed 3 channel headamps and many more that have built them. Show us valid tests where there was a reactive load and the 3 channel didn't outperform the two channel when they are the same amp otherwise. You can't just measure across a 15 ohm dummy load and pretend this represents real world performance.

The fact is, 3 channel amps with similar design and component quality sound better. If you refuse to use valid testing you can imply otherwise and seem supported but that isn't proof.

While you want to suggest people aren't measuring 3 channel amps to have better performance, THEY ARE! As I suggested previously, head over to headfi and ask... keeping in mind you MUST measure the same amp in 2 channel and 3 channel configuration to draw a valid conclusion. If you instead measure a "sorta somewhat similar but not the same" amp as the 2 channel versus a (different) amp as the 3 channel, the measurements are pretty much worthless trying to determine whether it was the additional channel that made it better or worse.

This is basic clear cut science and math. To resolve a variable you can't have several other unknown variables still. # of channels must be the only difference.

Last edited by !; 28th September 2011 at 10:53 PM.
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Old 28th September 2011, 11:32 PM   #43
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Quote:
Originally Posted by ! View Post
^ You can in fact fault a measurement that is supposed to be representative of an amp in general but the test is contrived to show it at its worst.

Similarly, testing methodology could be changed to show other amps at their worst. We can fairly say that when testing isn't done with common values, the tester is either ignorant or has some objective other than representing typical use.

You wrote you build one to power phones that can't be powered properly but that's a bit ambiguous because often when they aren't "powered properly" the result is poor sound, not just lack of volume that the headamp adds with more than unity gain.

I am not a fanboy of AMB's, it was merely one example of a 3 channel amp where one person mentioned benefits of the 3rd channel. There are many people who have designed 3 channel headamps and many more that have built them. Show us valid tests where there was a reactive load and the 3 channel didn't outperform the two channel when they are the same amp otherwise. You can't just measure across a 15 ohm dummy load and pretend this represents real world performance.

The fact is, 3 channel amps with similar design and component quality sound better. If you refuse to use valid testing you can imply otherwise and seem supported but that isn't proof.

While you want to suggest people aren't measuring 3 channel amps to have better performance, THEY ARE! As I suggested previously, head over to headfi and ask... keeping in mind you MUST measure the same amp in 2 channel and 3 channel configuration to draw a valid conclusion. If you instead measure a "sorta somewhat similar but not the same" amp as the 2 channel versus a (different) amp as the 3 channel, the measurements are pretty much worthless trying to determine whether it was the additional channel that made it better or worse.

This is basic clear cut science and math. To resolve a variable you can't have several other unknown variables still. # of channels must be the only difference.
Wow nice job not reading anything. If you would actually read the information in the links posted and some of the other articles you would understand how this works. But you don't, you refuse. You continue to tell me what sounds better and I have to, once again, tell you I don't care about your subjective ears. The three channel design is proven to be worse than a true ground in every situation. Even AMB's amps would be better if they were designed with that in mind. It's a proven fact. That makes you technically wrong. Which is probably the worst kind of wrong.

You can get angry all you like. The fact of the matter is real evidence has been offered that makes your theory incorrect. Getting mad about it isn't going to make it any less so.

Explain to me what problem a third channel is supposed to solve in the first place? Are you trying to say that it will have lower output impedance? Because that is 100% false. Are you trying to say that it will decrease noise and crosstalk? Again.. FALSE.

So exactly what is this magical third channel supposed to do then? Cost money and draw power is about all it does. To insinuate that it will increase the performance in any way is not what the evidence suggests. Saying it does because it sounds different/better is like telling me you can smell fear and expecting me to believe it.

This thread is not for the discussion of the merits of three channel stereo amps. There is already a thread for that. If you feel so strongly about the issue then you can discuss it there.

Here is the link.
3 Channel Headphone Amps & Virtual Grounds

If you have a problem with the testing method, then you can take it up with the author. So far, his methods are sound. If you think you can devise a test to prove it wrong, then be my guest. No amount of mindless ranting designed to sound insightful is going change my opinion. I require fact and measurement with repeatable results.
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Old 29th September 2011, 12:25 AM   #44
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^ Saying something sounds better is nothing like tell you I can smell fear, it is a subjective opinion many people share and stands up to blind ABX test scrutiny. If building things that sound better is not the goal, why are we here?

Your link establishes at least one thing - that this argument has been going on for more than a few months and personally, I see no reason to continue for a few more even if you feel repeating the same things already stated somehow makes a difference now.

You claim you require fact and measurement yet you try to claim data not obtained in a valid way to represent the argument is "fact". That in itself does not make your side of the argument wrong, but it does make your stance that you are stating a proven fact, wrong.

Last edited by !; 29th September 2011 at 12:33 AM.
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Old 5th October 2011, 02:52 AM   #45
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counter culture, your links do not work because of a session ID embedded in them. I don't know why you linked through a proxy but regardless, here they are working w/o a proxy session ID for others' reading.

NwAvGuy: Virtual Grounds & 3 Channel Amps
NwAvGuy: AMB Mini3 DIY Headphone Amp

On the Mini3 he pretends to do valid measurements but look at what he actually did. Testing at 15 ohms... how many 15 ohm headphones do you own? Most people have never seen such a beast. Publishing a rating of "poor" for THD of 0.45% into that 15 ohms but not even mentioning the power level... pretty fishy, anyone can make THD rise by pushing the power level. Crosstalk also at 15 ohms, but not even negative values??? Fishy.

The author makes a false assumption that the ground impedance is only from an inch of wire, does he think the positive and negative rail impedance is also only an inch of wire each too? He must then, so his argument is that your entire power supply impedance comes from the two inches of connecting wire.

False assumptions can predicate further false assumptions.

When criticism isn't justified, you don't drop everything and entertain someone.

For example, if I stated someone is too short to play basketball and the person wasn't short nor did they want to play basketball, would that person feel compelled to stop what they are doing and address the comment? Perhaps for an instant but not for long if at all.
I stand by my Mini3 review 100%. If you have factual evidence of where anything in that review is wrong, please let me know? But so far, in many months, what's there has not been proven wrong short of a battery life issue that I corrected.

In reality, there are plenty of low impedance headphones. And 400 mV into 15 ohms is something any iPod can manage at low distortion. But the Mini3 cannot. Etymotic, Ultimate Ears, Denon and many others have headphones that are below 32 ohms. And headphones like the AKG K701 also make the Mini3 fall onto its face. Many balanced armature IEMs dip below 10 ohms at some frequencies. I show examples in my Headphone Impedance article.

The power level at 20 Khz and 0.45% was 400 mV into 15 ohms. It was clearly specified. There's nothing "fishy" about that. Again, if you have factual evidence of where something is wrong, let me know?

Lots of headphone amps, especially portable ones, are specified into 16 ohm loads. The only way to verify those specs is to test into a similar load. The Mini3 is a portable headphone amp. If you want examples I can provide a dozen or more from FiiO to Leckerton. If you look on Amazon the most popular best selling portable headphones are 16 ohms.
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