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Comparison of components for driving an AKG K1000 headphone - Page 3

post #31 of 109
Quote:
Originally posted by mikeg
John Dunlavy makes the following points in his article:
- That those who claim to hear differences between cables do not fully grasp the power of the old "Placebo-Effect."
By definition, the placebo effect only occurs when the test subject can identify the respective conditions being tested before the experiment is conducted (i.e. cable A is on one switch, cable B on the other), or when the subject is led to believe that what he is about to hear is "supposed" to be better/worse than what he/she is used to.

In other words, the placebo effect cannot, by definition, affect the outcome of a random, double-blind test.

I bring these points up because I've heard major differences between cables in such tests, and could consistently identify one cable as being "better" than the other.

Quote:
- To say, as some do, that there are factors involved that competent engineers and scientists have yet to identify is utter nonsense and a cover-up for what should be called "pure snake oil and buzzard salve" - in short, pure "fraud".
This statement by Mr. Dunlavy is, in and of itself, pure hogwash (to put it kindly). I posted a quote in one of the infamous "cable" threads by a respected doctor and audiologist who commented that the current body of science is incapable of fully explaining how the human hearing system actually works. I also posted a similar quote from a well-know physicist, expressing an opinion held by many physicists, that the current body of science still cannot completely explain the behavior of electrical signals traveling through various substances, and the effects that other materials may have on such signals. So... if we don't know everything there is to know about electrical conduction, and we don't know everything about how the human ear/brain function, it follows that we surely can't explain everything about the "science" of cables, and it's possible that one cable may sound different than another, even if they "measure" identically using today's measurement devices.

I'm not saying that a lot of the cable "science" out there isn't snake oil; I'm just saying that just because there are dishonest people taking advantage of gullible "audiophiles" doesn't mean that all cable science (or the admitted lack of such) is fraud.
post #32 of 109
"I posted a quote in one of the infamous "cable" threads by a respected doctor and audiologist who commented that the current body of science is incapable of fully explaining how the human hearing system actually works. I also posted a similar quote from a well-know physicist, expressing an opinion held by many physicists, that the current body of science still cannot completely explain the behavior of electrical signals traveling through various substances, and the effects that other materials may have on such signals."

yes, i don't doubt that there are qualified people out there that believe it's possible there are cables that sound different from others... but there are many more that do not believe such things. quoting one or two "knowledgable" people doesn't really mean much when the vast majority of such "knowledgable" people disagree with the notion that a human can hear differences in a couple meters of cable.

now, it IS a fact that different sizes/types of cables do affect sound. this can be seen when we use much longer lengths... like maybe 100-1000ft of cable. then the differences are much larger. but in a couple meters?

i think we're confusing some issues here: yes, we will probably never FULLY understand the human body... and everyday we learn more about physics. so what? ...do we know enough to say that our Earth is a sphere, not flat?, despite the fact that we still cannot prove the big-bang theory? we discover new stars everyday, and yet we always look for the Sun to rise in the East every morning. ...there is enough evidence to support Mr. Dunlavy's claims.... and that is absolutely what science is about: using evidence to support a hypothesis. "absolute science" is an oxymoron... there is nothing "absolute" about science. but we do know enough to be able to say that we are more than sure that the world is not flat.

"This statement by Mr. Dunlavy is, in and of itself, pure hogwash (to put it kindly)."-- why? because "there are factors involved that competent engineers and scientists have yet to identify?" is that why you think Mr. Dunlavy is talking bull?

As science stands today, Mr. Dunlavy is mostly correct. And I wouldn't be placing any bets against him for the next couple centuries.

and besides... i think that Dunlavy's main point wasn't that cables do not have any effect on the quality of electrical transmission... i think his main objection was all the bull that cable makers use to advertise their products... such as improper descriptions of skin-effect, induction, capacitance... and more blatant bull like "golden ratio", "speed of light technology," etc...
post #33 of 109
Thread Starter 
Quote:
Originally posted by darkclouds
So it would be plausible, in your case mikeg, that the K1000 may not be refined enough (for you) to reveal the differences between two very different levels of amp/preamp.

Are you able to discern between the amps/preamp combos through your speakers?
I don't use speakers. According to a representative at Divergent Technologies, use of the Passive TIDT passive preamp with the AQ-1005DT is higher quality than using an integrated amp. (i.e., with its own volume control). So, although it's possible that my ears don't pick up a difference, it's not too likely.
post #34 of 109
Quote:
Originally posted by Orpheus
yes, i don't doubt that there are qualified people out there that believe it's possible there are cables that sound different from others...
Actually, I didn't say that anyone believed it's possible that cables sound different. What I said is that the following are accepted facts in the fields of audiology and physics:
1) We don't know everything about how the human ear/brain "hear"
2) We don't know everything about how electrical signals interact with many kinds of material

Given those two accepted facts, Mr. Dunlavy's assertion that

To say, as some do, that there are factors involved that competent engineers and scientists have yet to identify is utter nonsense and a cover-up for what should be called "pure snake oil and buzzard salve" - in short, pure "fraud"

is logically untenable.



Quote:
quoting one or two "knowledgable" people doesn't really mean much when the vast majority of such "knowledgable" people disagree with the notion that a human can hear differences in a couple meters of cable.
I don't know if it's fair to say that "the vast majority of such knowledgeable people disagree with the notion that a human can hear differences in a couple meters of cable." Do we really have a reliable survey of reputable physicists and audiologists? If we did, I think you'd be surprised by the results -- most good scientists wouldn't make such a foolish statement, knowing the gaps that exist in our knowledge of these two fields, and especially how these two fields interact.



Quote:
i think we're confusing some issues here: yes, we will probably never FULLY understand the human body... and everyday we learn more about physics. so what? ...do we know enough to say that our Earth is a sphere, not flat?, despite the fact that we still cannot prove the big-bang theory? we discover new stars everyday, and yet we always look for the Sun to rise in the East every morning. ...there is enough evidence to support Mr. Dunlavy's claims.... and that is absolutely what science is about: using evidence to support a hypothesis.
The difference is that in the former examples, the evidence CLEARLY supports those theories. In the case of Mr. Dunlavy's claims, the evidence doesn't support it; it's the lack of evidence -- namely a measurable difference between cables -- that is used to "support" his position.


Keep in mind that I agree with Mr. Dunlavy to the extent that he says many cable manufacturers are full of it. I simply disagree with his statement that it's "fraud" to say that there are factors involved in cable design that people don't understand or have yet to identify. They said that about quarks thirty years ago...
post #35 of 109
k... yeah, i must admit, i don't have a survey of physicists that do or do not believe. maybe someday i will... my comments are based only on the number of people i have talked to myself. and there hasn't been a single "scientist" that has allowed that a short length of cable can make a difference.

but i understand your points.

wallijon, .... i talked to some AKG reps at the AES convention where they were demoing the k1000s... and they said they only recommend using a pure class A amp... and that's why i spent so much for a Monarchy SM-70 pro. but the crown sounds fine huh? also, isn't the crown a bit high powered? 40wpc @ 8 ohms or 4 ohms? pro stuff is usually quoted at 4 ohms.

anyway, the monarchy is only 25wpc @ 8 ohms, but i still have to turn the volume WAYYY down... i think a 40wpc amp is just too much power.

however... if you're finding that it's not too much, i think you're having the same trouble i first had. i used to be using a Alesis RA-100... it's 100wpc @ 4 ohms!... and hooked up to my Alesis Monitor Two's (10" woofers)... they are LOUD. ...but when i connected my k1000s to them, at a volume that would have drove a normal person deaf, the k1000 was only moderately loud. thus i concluded that the ra100 just wasn't adequate for the k1000.

i suggest trying another amp to see if there are more efficient amps out there for the k1000.
post #36 of 109

Bottlehead Northwest Report thread

If you want a good explaination of why some SS amps can't deliver high sound levels with the K1000 earspeaker, and other amps can, read Doc B's excellent postings in the attached thread from Sept '02.

"... a SS amp with a low output impedance may have a tough time delivering the voltage swing necessary because it's typical 8 ohm power rating drops like a rock into higher impedance loads."

"One interesting design exercise is an amp for the AKG K1000. This is a very insensitive headphone, at 74dB/mW. To get to 110 dB we will need about 4W (not sure why the reviews claim 7W is needed, I guess they like about 114 dB peaks). 4W at 120 ohms requires a rms drive of 22V, which is about 31V peak. At the roughly 11:1 turns ratio required for our 6N1P to see a 15K load reflected from 120 ohms that means we need to get 341V peak drive into our transformer primary. Not gonna happen.

So we need to look at another tube with a lower plate impedance that doesn't require such a high step down ratio. How about a tube that will work into a 5k:120ohm transformer? This is about a 6.5:1 turns ratio, so now we only need to see about 200V peak swing from our tube. Still too big a job for a lot of small signal tubes like the 6C45 or 417A, which will work very nicely into a 5K load, but we can see that something along the lines of a 300B running at 400V might do the trick.

The 7868 used in a Fisher 400 is running at 400V. That means that you can get 200V peak swing clean from each tube in the PP configuration, or about 286Vrms into the trafo primary. Now a Fisher 400 has a 6600ohm primary. 6600 ohms into 4 ohms is a 40:1 ratio. So 286 vrms into the primary is 7.15Vrms into the secondary. Into 120 ohms that is .426W. At 74 dB/mW sensitivity that is about 100dB peak.

If you go to the 16 ohm tap, 6600 ohms into the 16 ohm secondary gives you about a 20:1 ratio. So now you 286Vrms gives you about 14.3Vrms into 120 ohm headphones, and you will see about .826W into a 120 ohm load, giving you about 104 dB."

For the complete thread:

http://www4.head-fi.org/forums/showt...sher+400+K1000
post #37 of 109

How about 6AS7/6080 in SRPP ?

Quote:
Originally posted by mkmelt
If you want a good explaination of why some SS amps can't deliver high sound levels with the K1000 earspeaker, and other amps can, read Doc B's excellent postings in the attached thread from Sept '02.

"... a SS amp with a low output impedance may have a tough time delivering the voltage swing necessary because it's typical 8 ohm power rating drops like a rock into higher impedance loads."

"One interesting design exercise is an amp for the AKG K1000. This is a very insensitive headphone, at 74dB/mW. To get to 110 dB we will need about 4W (not sure why the reviews claim 7W is needed, I guess they like about 114 dB peaks). 4W at 120 ohms requires a rms drive of 22V, which is about 31V peak. At the roughly 11:1 turns ratio required for our 6N1P to see a 15K load reflected from 120 ohms that means we need to get 341V peak drive into our transformer primary. Not gonna happen.

So we need to look at another tube with a lower plate impedance that doesn't require such a high step down ratio. How about a tube that will work into a 5k:120ohm transformer? This is about a 6.5:1 turns ratio, so now we only need to see about 200V peak swing from our tube. Still too big a job for a lot of small signal tubes like the 6C45 or 417A, which will work very nicely into a 5K load, but we can see that something along the lines of a 300B running at 400V might do the trick.

The 7868 used in a Fisher 400 is running at 400V. That means that you can get 200V peak swing clean from each tube in the PP configuration, or about 286Vrms into the trafo primary. Now a Fisher 400 has a 6600ohm primary. 6600 ohms into 4 ohms is a 40:1 ratio. So 286 vrms into the primary is 7.15Vrms into the secondary. Into 120 ohms that is .426W. At 74 dB/mW sensitivity that is about 100dB peak.

If you go to the 16 ohm tap, 6600 ohms into the 16 ohm secondary gives you about a 20:1 ratio. So now you 286Vrms gives you about 14.3Vrms into 120 ohm headphones, and you will see about .826W into a 120 ohm load, giving you about 104 dB."

For the complete thread:
http://www4.head-fi.org/forums/showt...sher+400+K1000
I had calculated last night. 6080/6AS7 in SRPP can delivery
more than 20V. It even no need a matching transformer. I don't know how it sound but I think it is workable. JJ ECC99 also can working in simulair condition. May be Parallel It and work in SRPP will be more better.
post #38 of 109
Although the K1000's aren't the most revealing headphones in the world, with the right amplification, they sound remarkable. I find that the best cable to use with my K1000's is no cable at all. I drive them directly with an AKG K1000 class-A amplifier (built by SAC) designed specifically for that can. I have not heard any better amp/cable for that can that I possess, although as I recall the V20 at the HeadRoom show did a slightly better job.

Anyone else out there using the AKG K-1000 amplifier?
post #39 of 109
kwkarth, Greg Freeman also has the the SAC.

If the contention is that the k1000 should be driven from Class A, then why is the sound out of a nOrh SE9 good? Is the SRPP a class A tube amp? Obviously there are other viable soultions to driving k1000s. My take is that so long as there are no dc blocking caps, and provided the headphone jack is directly coupled to the speaker outputs (instead of using a dicreet, isolated, low current op amp) the sound can be acceptable. Perhaps not sublime, like the AKG SAC...

as to the crown being too powerful, I'll just have to swap in larger knobs for finer adjustment; and perhaps a knob stop... I may even swap in an ADS ganged volume controller.
post #40 of 109
Thread Starter 
Quote:
Originally posted by kwkarth
Although the K1000's aren't the most revealing headphones in the world, with the right amplification, they sound remarkable. I find that the best cable to use with my K1000's is no cable at all. I drive them directly with an AKG K1000 class-A amplifier (built by SAC) designed specifically for that can. I have not heard any better amp/cable for that can that I possess, although as I recall the V20 at the HeadRoom show did a slightly better job.

Anyone else out there using the AKG K-1000 amplifier?
Which can is more revealing than the K1000?
post #41 of 109
Quote:
Which can is more revealing than the K1000?
Stax or Etymotic headphones.
post #42 of 109
I have the ETY 4S and it is not more revealing than my modified AKG 1000. Maybe I should get the Omegas as well.
post #43 of 109
Quote:
Originally posted by wallijonn
kwkarth, Greg Freeman also has the the SAC.

If the contention is that the k1000 should be driven from Class A, then why is the sound out of a nOrh SE9 good?
The nOhr SE9 is a class A amp.
post #44 of 109
thanks, I must of missed that. I too have been contemplating a nOrh SE9 purchase. My one reservation is that I was once into tube rolling (back in the days of Dynaco tube preamps and amps) and I don't like the nagging thoughts in the back of my head that say "Maybe we can make it sound better if we change this tube, or this resistor, or this capacitor..." I definitely have the tinker in me.
post #45 of 109
Thank God I know nothing about tubes or I would be tinkering also.

PLEASE - everyone - for my wallet and sanity - don't tell me anything about changing tubes!
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