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post #136 of 221
Quote:
Originally Posted by scompton View Post
I have a question on the table. The last column is labeled R1 Power. Is that measured after R1?
R1 power is power measured across R1. This will tell you what sort of resistor rating to get so that it doesn't get over loaded and blown.

Quote:
Originally Posted by scompton View Post
Navyblue, when you say you tailor the resistor to the K501, what do you mean? I assume you're using a value of R2 that matches or is higher than the impedance of K501, so more of the current and voltage is supplied to the headphone instead of going though R2.
My K501 is 120 ohms and has a maximum power rating of 200 mW.

The impedance of the headphone would affect how much power that it receives (for this particular circuit). The higher the impedance, the less power that it will receive. So I tailored all the resistor values to the impedance and maximum power rating of the headphone so that I get as much power as possible without blowing the headphone driver, while maintaining the 120 ohms impedance. Which means all of the R1, R2 and R3 values are modified.

Btw, as a safety measure, I split R2 into 3 resistors in parallel. With a single R2 resistor, if for some reason it malfunctions, there will be a power spike to the headphone, which might or might not ruin the headphone. By splitting it to 3 resistors is parallel, the power spike when one resistor fail is lessened, and my altercation ensures that the power spike would still be below the maximum power handling of the headphone.

Yes, I baby my headphone that much.
post #137 of 221
Quote:
Originally Posted by chesebert View Post
Correct me if I am wrong, but change in FR is a form of "loss of detail". Let's suppose that a 10khz component of the composite wave taken at a particular instant during a busy music passage is only -50dB, by taking another 3dB or more off of that you are basically pushing that frequency component closer toward the noise thereby reducing your S/N, and accordingly that's perceived as a loss of detail.
I suppose you could look at it that way. Of course in doing so, that would make anything below dead flat FR a relative loss of detail and any thing above it a relative addition of detail. It would, almost by definition, make S/N the spec that defines detail. The vinyl guys won't like you much. Neither will the tube guys. But we could begin to analyze the FR curves of all audio devices and define them in terms of the presence of detail instead of tone or character. I'm not sure it would be at all useful. But we could look at it that way.

Tim
post #138 of 221
Quote:
Originally Posted by tfarney View Post
I suppose you could look at it that way. Of course in doing so, that would make anything below dead flat FR a relative loss of detail and any thing above it a relative addition of detail. It would, almost by definition, make S/N the spec that defines detail. The vinyl guys won't like you much. Neither will the tube guys. But we could begin to analyze the FR curves of all audio devices and define them in terms of the presence of detail instead of tone or character. I'm not sure it would be at all useful. But we could look at it that way.

Tim
FYI most well constructed phono/tube preamp have very flat FR; vinyl is overall superior because of theoretically infinite resolution and tube is preferred because of their lack of higher ordered harmonics, both of which are not really related to the FR of the system.

Stereophile: Audio Research Reference 3 line preamplifier

I think this is an informative read
Fourier series - Wikipedia, the free encyclopedia
post #139 of 221
Quote:
Originally Posted by chesebert View Post
FYI most well constructed phono/tube preamp have very flat FR; vinyl is overall superior because of theoretically infinite resolution and tube is preferred because of their lack of higher ordered harmonics, both of which are not really related to the FR of the system.

Stereophile: Audio Research Reference 3 line preamplifier

I think this is an informative read
Fourier series - Wikipedia, the free encyclopedia
I won't argue with any of that today as it was not why I referred to tubes and vinyl. I referred to them because they both have a higher noise floor than digital or solid state, which was part of your rationale for altered FR = loss of detail.



Tim
post #140 of 221
Quote:
Originally Posted by scompton View Post
I've been reluctant to buy a dedicated amp since I don't listen to dynamic headphones much any more. I am thinking of building a Staving Student Millet Hybrid. I like $50 and some of my time a lot better than $300+. I'm cheap.
From my subjective unscientific comparison, there were two critical issues.
1. Is the music complex and difficult to present (many different sounds at the same time). The pop song wasn't much affected by the differences between the amps.
2. Do you enjoy the music as much as you expect to from your current amp? The two difficult tracks were more enjoyable from the XCAN.

And there was also the usual observation, that the cans differed much more in style than the amps differed in style. EDIT: However, although the cans differ more in style of presentation than the amps, they both performed a tad better from the xcan - but only noticeable for me in the difficult passages.

Also, if your amp is very good (mine isn't extremely good) then it might well be more similar to a dedicated headphone amp (you would have to test that to find out, I guess).
post #141 of 221
Quote:
Originally Posted by Navyblue View Post
R1 power is power measured across R1. This will tell you what sort of resistor rating to get so that it doesn't get over loaded and blown.



My K501 is 120 ohms and has a maximum power rating of 200 mW.

The impedance of the headphone would affect how much power that it receives (for this particular circuit). The higher the impedance, the less power that it will receive. So I tailored all the resistor values to the impedance and maximum power rating of the headphone so that I get as much power as possible without blowing the headphone driver, while maintaining the 120 ohms impedance. Which means all of the R1, R2 and R3 values are modified.

Btw, as a safety measure, I split R2 into 3 resistors in parallel. With a single R2 resistor, if for some reason it malfunctions, there will be a power spike to the headphone, which might or might not ruin the headphone. By splitting it to 3 resistors is parallel, the power spike when one resistor fail is lessened, and my altercation ensures that the power spike would still be below the maximum power handling of the headphone.

Yes, I baby my headphone that much.
Do you mean, you split the one parallel resistor into 3 resistors that are put in series in place of R2, or you replicate that connection between the left channel and ground 3 times? So if you wanted 120 ohms, either 3 40 ohm resistors in the first case or 3 360 ohm resistors in the second case.

Quote:
Originally Posted by chesebert View Post
I think this is an informative read
Fourier series - Wikipedia, the free encyclopedia
Maybe for you, but it's been 30 years since I've seen that type of math. It's way beyond me now
post #142 of 221
Quote:
Originally Posted by scompton View Post
DefectiveAudioComponent and pp312, I hear a difference in my DT831 between my NAD and a portable amp plugged into the wall. The DT831 has a reputation for being bass shy which it is not out of the NAD. Some of the difference I'm sure is attributable to the portable amp not being up to driving the DT831, but it does mimic the charts in the Meier article to some extent. The DT831's impedance is 250 ohm and I'm using a 150 ohm adapter, so it's 400 ohms. That is asking a lot for a portable amp, even if it's not running off of a battery. Unfortunately, I only have a portable amp for comparison.
Just a few general observations. First, I'm not much interested in the technical stuff. I played around with series resistors but could hear nothing other than attenuation; no subjective effect on frequency response even up to 560 ohms. But then of course I have the Senn 650, so lower impedance phones may be more affected. As for you hearing more bass from the NAD, this is in line with my experience and I've mentioned in a previous post that integrateds generally seem to have more bass. Whether this is because of a poorer damping factor I don't know; I only know that in most cases I prefer it, as it provides a fuller, warmer sound with no apparent loss of detail. However, I'm into classical/orchestral, where bass definition is less important than overall scale and weight; others with different priorities may claim that integrateds lose definition.

This is where it's important to define one's terms. I advocated here years ago that when describing the sound of components posters preface their remarks with a description of their musical tastes and general HP preferences. It's just no good someone into electronica posting that amp A beats the pants off B because of its incredible bass definition when someone like myself might come along and find that amp A, while being very taut in the bass, is quite harsh on strings and cymbals--instruments which our original poster may never have heard in his life and cares nothing about. Likewise when someone posts that he's just bought Senn 650s and hates them, it's useful to know that he's coming from three Grados and an AKG701! This is not a scientific forum (despite the recent spate of posts!). There are few absolutes here outside of resistor maths. So long as we fail to define where we're coming from there'll be misunderstanding and the whole point of the forum--to share our enjoyment of the hobby and disseminate information--will be lost.

Incidentally, just coming back to your point, if you find your DT831 sounds less lean with the NAD then you've discovered synergy, yet another factor too rarely considered here. No HP is neutral; the frequency responses tell you that (even if they tell you not much else). No amp, dedicated or otherwise, no matter how expensive, will suit every HP equally well. In that sense we should really be talking in combinations--i.e.: "the Little Dot Mk V sounds great with the AKG701 on my Metallica CDs!". Anything much less specific is inherently confusing. But hey, I'm harping...a bad habit of mine. Sorry....
post #143 of 221
Synergy is right. I brought home my HD580 to try it and it's horrible. It's incredible harsh, especially on the high end. Kind of reminds me of one of the few times I've heard a Grado. It's the exact opposite of the DT831. It's pretty much unlistenable. From the portable amp I use at work, they're among my bassiest headphones. The changes in the DT831 is is minor in comparison.

Actually, the mids aren't too bad when they're not being overwhelmed by the treble.

Edit: Trying different tracks, it appears that what's harsh is trumpet and alto sax. I tried some of my bass test tracks and there is deep rumbling bass. It's just when a trumpet comes in, it overwhelms everything else. There must be one nasty spike in whatever frequency trumpets and alto sax play in.
post #144 of 221
Quote:
Originally Posted by scompton View Post
Synergy is right. I brought home my HD580 to try it and it's horrible. It's incredible harsh, especially on the high end.
I couldn't abide the 580 either--much too harsh on classical. I know they have a following and I don't want to dis them (but I will anyway )---but, yeah, the 650 to my ears is in a different league altogether. They say the 580/600 are great on classical, but really with that forward upper mid/lower treble I'd have thought they were better with rock. The 650 seems to have been tailored with classical in mind.
post #145 of 221
I was listening to jazz, but I agree about them not being good for classical. I have plenty of headphones that are better for classical - SR-Gamma, K500/K400/K401, QP85, even the DT880.

I'm planning on paring down my headphones, and they'll probably be going.
post #146 of 221
Quote:
Originally Posted by scompton View Post
Do you mean, you split the one parallel resistor into 3 resistors that are put in series in place of R2, or you replicate that connection between the left channel and ground 3 times? So if you wanted 120 ohms, either 3 40 ohm resistors in the first case or 3 360 ohm resistors in the second case.
It's the second case.

3x360 ohms resistors in parallel if you are aiming for 120 ohms for R2.

3x40 ohms makes no difference to a single 120 ohms if any one of the resistor fail.
post #147 of 221
I want to make sure I understand this



So losing a resistor in the diagram on the left is worse than losing a resistor on the right? I'd think you'd end up with 80 ohms either way. Or am I completely misunderstanding what you're doing?

I'm new to all of this. I had some electrical theory in Physics back in the 70s, but it had nothing to do with electronics. The closest I've come to electronics was a computer arch class where we logically designed ALUs. But it was strictly logic problems on paper. It didn't take in consideration how components effect electricity.
post #148 of 221
Quote:
Originally Posted by scompton View Post
I want to make sure I understand this



So losing a resistor in the diagram on the left is worse than losing a resistor on the right? I'd think you'd end up with 80 ohms either way. Or am I completely misunderstanding what you're doing?

I'm new to all of this. I had some electrical theory in Physics back in the 70s, but it had nothing to do with electronics. The closest I've come to electronics was a computer arch class where we logically designed ALUs. But it was strictly logic problems on paper. It didn't take in consideration how components effect electricity.
I believe a resistor typically fails open in most cases, meaning current would stop flowing through them. All the explanation assume that it is the scenario.

If the resistor fail as closed circuit, it doesn't quite matter in this case as the headphone would practically stop receiving power anyway as the short circuit would draw away the current. But if the R1 fails as open circuit, I have no solution.

The purpose of R2 is to reduce the impedance both on the amplifier end and headphone end.

So back to the point, with the series configuration, if any one of the three resistors fail, no current will be able pass through all the three resistors, no matter which one of them fails. Which practically means that the effect is no different from having a single 120 ohms resistor fail. In the case of resistor failure, the impedance lowering effect of R2 will be removed.

The effective impedance from the amplifier end will be:
R1 + R3 + headphone's impedance

The effective impedance from the headphone end will be:
R1 + R3

With the parallel configuration, when one of the resistor fail, impedance on both the amplifier and headphone ends will still increase, but comparatively not as much. The advantage of doing so is there will be two more resistors to share the power load channeled to the headphone.

Impedance from the amplifier end will be:
R1 + [R2-1 || R2-2 || (R3+headphone's impedance)]

Impedance from the headphone end will be:
R3 + (R2-1 || R2-2 || R1)

In short, in either series or parallel, we don't end up with 80 ohms effective R2 resistance when a resistor fail. In series we'd get infinite resistance as the circuit is open. And in parallel we'd get 360/2=180 ohms.

I am not an electronic guy either, and my ignorance of electrical jargon is preventing me from explaining more clearly/properly.
post #149 of 221
I didn't realize that when resistors fail, they no longer carry current. I was thinking of it more as a short.
post #150 of 221
Quote:
Originally Posted by scompton View Post
I didn't realize that when resistors fail, they no longer carry current. I was thinking of it more as a short.
I have no idea as well, but if they fail as a short it isn't a problem for the headphone. Just want to have my bases covered.
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