johnferrier said:
For many components, the leads provide absolutely no heat path. Ic's and transistors will have wirebonds, which are not designed for heat transfer. Only the solder bump technology will be thermally doing anything with the leads, but those chips are already upside down.
The surface mounts will, but only through the leads, not the top surface. The top will usually be just encapsulant, with no thermal properties.
Cheers, John
Infinite Earth/Foundation Can Be Good........
Glueing those components to substrate/heatsink will cause cooler running no question - epoxy encapsulations get hot and dragging heat away from them will allow somewhat cooler running for the internals.
Mounting the active devices to an earthed backplane allows mechanically stable P-P wiring and least parasitics no question.
It also allows optimum and effectively infinite earthing techniques.
I built a DAC on the edge of a sheet of 0.8 mm copper using P-P techniques and the result was spectacular.
Effectively the DAC stage local earth was quite infinite, and this paid sonic dividends bigtime in terms of effortlessness and solid stability.
Heatsinking however was not an issue in this case.
Eric.
Glueing those components to substrate/heatsink will cause cooler running no question - epoxy encapsulations get hot and dragging heat away from them will allow somewhat cooler running for the internals.
Mounting the active devices to an earthed backplane allows mechanically stable P-P wiring and least parasitics no question.
It also allows optimum and effectively infinite earthing techniques.
I built a DAC on the edge of a sheet of 0.8 mm copper using P-P techniques and the result was spectacular.
Effectively the DAC stage local earth was quite infinite, and this paid sonic dividends bigtime in terms of effortlessness and solid stability.
Heatsinking however was not an issue in this case.
Eric.
Yes, I think some heatsinking is possible through the leads and the encapsulation epoxy. I know that touching a device (JFET current source) causes a change in it's operating point. As John Sully mentions, the small wires within a device will not conduct much heat (I think they will conduct some small amount heat).
Also, I expect that a hefty ground plane is a plus. Steve made me a bit worried about adding parasitic components (very small capacitors and very large resistors). Trying to find information on the internet I found that the encapsulation epoxy has about a 3.5-4.0 dielectric absorption. Compared to 2.1 Teflon and about 4 for PCB material (FR4). It's good to think through these things. My thinking now is that using a thin glue line to a ground plane shouldn't be much different than a ground plane used in a printed circuit board (exactly the same leads, similar parasitics etc).
Thanks for a few of your thoughts on this, Eric.
Going back to cable distortion measurements, to some extent we are testing the capabilities of the test equipment. And this has been pointed out. At such an extreme low signal level, how do we know the measurements are correct? Following the procedure for NIST calibration traceability, a meter of 3-10 times accuracy can be used to calibrate/verify another meter. I wonder how distortion meters are calibrated. Also, Sy's idea of a Gauge R & R (Repeatability and Reproducibility) study can also be used to verify a meter's capability, but I'm not very familiar with what is involved with this. What may be audible, yet escape notice of a meter is an even more interesting question (for another thread).
JF
Also, I expect that a hefty ground plane is a plus. Steve made me a bit worried about adding parasitic components (very small capacitors and very large resistors). Trying to find information on the internet I found that the encapsulation epoxy has about a 3.5-4.0 dielectric absorption. Compared to 2.1 Teflon and about 4 for PCB material (FR4). It's good to think through these things. My thinking now is that using a thin glue line to a ground plane shouldn't be much different than a ground plane used in a printed circuit board (exactly the same leads, similar parasitics etc).
Thanks for a few of your thoughts on this, Eric.
Going back to cable distortion measurements, to some extent we are testing the capabilities of the test equipment. And this has been pointed out. At such an extreme low signal level, how do we know the measurements are correct? Following the procedure for NIST calibration traceability, a meter of 3-10 times accuracy can be used to calibrate/verify another meter. I wonder how distortion meters are calibrated. Also, Sy's idea of a Gauge R & R (Repeatability and Reproducibility) study can also be used to verify a meter's capability, but I'm not very familiar with what is involved with this. What may be audible, yet escape notice of a meter is an even more interesting question (for another thread).
JF
Originally posted by johnferrier
Yes, I think some heatsinking is possible through the leads and the encapsulation epoxy. I know that touching a device (JFET current source) causes a change in it's operating point. As John Sully mentions, the small wires within a device will not conduct much heat (I think they will conduct some small amount heat).
Hi John, Yes locking active components to a thermal coupler ought to stabilise operating points.
Also, I expect that a hefty ground plane is a plus. Steve made me a bit worried about adding parasitic components (very small capacitors and very large resistors). Trying to find information on the internet I found that the encapsulation epoxy has about a 3.5-4.0 dielectric absorption. Compared to 2.1 Teflon and about 4 for PCB material (FR4). It's good to think through these things. My thinking now is that using a thin glue line to a ground plane shouldn't be much different than a ground plane used in a printed circuit board (exactly the same leads, similar parasitics etc).
These parasitics should be shunt to ground and cause only loading to ground and not intercomponent coupling, and will be rather less than any pcb.
Different DA's of different materials cause different spectral loadings and sonics - IME different pcb materials add particular sonic characters.
Encapsulation materials too - ceramic DIP opamps sound fundamentally different to epoxy encapsulated DIP opamps.
Thanks for a few of your thoughts on this, Eric.
No worries - anytime.
Going back to cable distortion measurements, to some extent we are testing the capabilities of the test equipment. And this has been pointed out. At such an extreme low signal level, how do we know the measurements are correct? Following the procedure for NIST calibration traceability, a meter of 3-10 times accuracy can be used to calibrate/verify another meter. I wonder how distortion meters are calibrated. Also, Sy's idea of a Gauge R & R (Repeatability and Reproducibility) study can also be used to verify a meter's capability, but I'm not very familiar with what is involved with this. What may be audible, yet escape notice of a meter is an even more interesting question (for another thread)
The first error as I see it is that sinewaves do not and cannot replicate dynamic behaviours of an arbitary or music waveform, but are none the less a start in measurements.
I think that it should be kept in mind that these measurements are an attempt to quantify heard differences in different cables, and if the tests are not revealing then perhaps the test methodology requires modifying.
There are plenty of sonic effects that sinewave TDH+N testing does not reveal.
Eric.
Yes, I think some heatsinking is possible through the leads and the encapsulation epoxy. I know that touching a device (JFET current source) causes a change in it's operating point. As John Sully mentions, the small wires within a device will not conduct much heat (I think they will conduct some small amount heat).
Hi John, Yes locking active components to a thermal coupler ought to stabilise operating points.
Also, I expect that a hefty ground plane is a plus. Steve made me a bit worried about adding parasitic components (very small capacitors and very large resistors). Trying to find information on the internet I found that the encapsulation epoxy has about a 3.5-4.0 dielectric absorption. Compared to 2.1 Teflon and about 4 for PCB material (FR4). It's good to think through these things. My thinking now is that using a thin glue line to a ground plane shouldn't be much different than a ground plane used in a printed circuit board (exactly the same leads, similar parasitics etc).
These parasitics should be shunt to ground and cause only loading to ground and not intercomponent coupling, and will be rather less than any pcb.
Different DA's of different materials cause different spectral loadings and sonics - IME different pcb materials add particular sonic characters.
Encapsulation materials too - ceramic DIP opamps sound fundamentally different to epoxy encapsulated DIP opamps.
Thanks for a few of your thoughts on this, Eric.
No worries - anytime.
Going back to cable distortion measurements, to some extent we are testing the capabilities of the test equipment. And this has been pointed out. At such an extreme low signal level, how do we know the measurements are correct? Following the procedure for NIST calibration traceability, a meter of 3-10 times accuracy can be used to calibrate/verify another meter. I wonder how distortion meters are calibrated. Also, Sy's idea of a Gauge R & R (Repeatability and Reproducibility) study can also be used to verify a meter's capability, but I'm not very familiar with what is involved with this. What may be audible, yet escape notice of a meter is an even more interesting question (for another thread)
The first error as I see it is that sinewaves do not and cannot replicate dynamic behaviours of an arbitary or music waveform, but are none the less a start in measurements.
I think that it should be kept in mind that these measurements are an attempt to quantify heard differences in different cables, and if the tests are not revealing then perhaps the test methodology requires modifying.
There are plenty of sonic effects that sinewave TDH+N testing does not reveal.
Eric.
mrfeedback said:
It should be kept in mind that these measurements are NOT an attempt to quantify heard differences in cables.
These measurements are an attempt to reproduce the distortion measurements that John Curl has been doing in order to determine whether or not the distortion he's been measuring is being produced by the cables themselves.
Sure. But that's not the purpose of these particular measurements. With these particular measurements, we already have someone who has been measuring simple harmonic distortion using a simple sinewave stimulus.
By the way, before Bruno did the measurements I'd requested in order to try and reproduce John's results, he also did a much more comprehensive series of measurements to see if he could turn up anything.
Here's Bruno's original report on these measurements which he originally posted on the rec.audio.high-end newsgroup under the title "Some serious cable measurements with interesting results."
Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing. The test equipment was an Audio Precision System 2 Cascade. Test objects were a handful of cables of varying construction and claims to audiophile performance.
Distortion: Not only sine wave, but also extremely complex full-spectrum multitone testing (including signal sequences derived from actual music). There was no difference between the cables tested.
Phase noise. While this would have shown up anyway in the above tests, it was separately checked at frequencies well above the audio band. Nothing showed up.
"Micro phase shifts". The AP2's resolution is so good you can read the length of a 1m cable by measuring the phase difference between input and output. Apart from this, nothing turned up.
In-Out difference. Actually, two different cables of equal length were fed the above distortion test signals in opposite phase. The two outputs were summed through a trimmable network to null the output. Well, the output nulled completely (better than 120dB across the audio band).
In short, apart from a constant time delay of a few nanoseconds (depending on length), an interconnect will have the same voltage at its output as at its input.
The rest of his post (which goes on to consider other aspects such as induced noise and microphonics) can be found here:
http://groups.google.com/groups?q=+...elm=B77vb.193311$mZ5.1434271@attbi_s54&rnum=1
se
Hi,
Stevie,
Within the context of your thread I have a nagging question.
Would you like me to get in touch with Dr. W. De Ceuninck and see what and how he measured or is that beyond the scope of this thread?
Or tell me what exactly it is you'd like to know from him, etc...
That is, assuming he can and is willing to share his findings of course.
I will contact him either way if only for the purpose of rekindling a long standing friendship so let me know.
Cheers,
Stevie,
Within the context of your thread I have a nagging question.
Would you like me to get in touch with Dr. W. De Ceuninck and see what and how he measured or is that beyond the scope of this thread?
Or tell me what exactly it is you'd like to know from him, etc...
That is, assuming he can and is willing to share his findings of course.
I will contact him either way if only for the purpose of rekindling a long standing friendship so let me know.
Cheers,
Yikes!
So, earlier this evening I'm sitting at the computer doing something which I no longer remember when suddenly I hear this huge crash which caused the whole house to shake.
"WHAT THE !@#$% WAS THAT!?"
At first I thought perhaps a plane had crashed seeing as my house is in the landing path of the local executive airport which has everything from kit planes to Gulfstreams flying directly over my house at just a few hundred feet on a rather routine basis.
So I run out of the house to find this scene in my front yard:
This is my neighbor's truck. They live in the house across the street, with the Christmas lights you can see just above the truck's cab.
He'd had the truck parked on my side of the street about 15 feet from my driveway, which would be back toward the left in the photo (the photo was taken from my front porch while turned just to the right).
A drunk driver, who had neither a driver's license nor insurance came speeding down my street, crashed into the rear of the truck launching it about 50 feet until it crashed into the tree (it's not as dramatic looking in the photo, but the truck's chassis was bent considerably right in the middle between the cab and the bed).
Meanwhile, the drunk driver's car careened off that truck and into the rear end of the same neighbor's SUV which was parked directly across the street in front of another neighbor's house (his nextdoor neighbor to the left in the photo).
Amazingly, the drunk driver had no injuries and ran off down the street after the accident.
Truned out that he lived just down the street and had gone home, changed his clothes and then returned to the scene, claiming it was his cousin who was driving the car.
The police arrived, didn't buy his story (the neighbors across the street saw him run from the scene), handcuffed him and hauled him off.
The amazing part is that I had a car parked in my driveway and one parked in the street directly in front of my house. The truck in the photo was parked directly behind the car in the street about 30 feet in back of it.
Somehow, when the truck was launched, it went at an angle such that it went right between my two cars even though there was less than a foot of clearance to either side.
The somewhat scary part is that I was out standing in front of that same truck a couple of hours earlier while raking up some leaves.
Crazy night.
se
So, earlier this evening I'm sitting at the computer doing something which I no longer remember when suddenly I hear this huge crash which caused the whole house to shake.
"WHAT THE !@#$% WAS THAT!?"
At first I thought perhaps a plane had crashed seeing as my house is in the landing path of the local executive airport which has everything from kit planes to Gulfstreams flying directly over my house at just a few hundred feet on a rather routine basis.
So I run out of the house to find this scene in my front yard:
An externally hosted image should be here but it was not working when we last tested it.
This is my neighbor's truck. They live in the house across the street, with the Christmas lights you can see just above the truck's cab.
He'd had the truck parked on my side of the street about 15 feet from my driveway, which would be back toward the left in the photo (the photo was taken from my front porch while turned just to the right).
A drunk driver, who had neither a driver's license nor insurance came speeding down my street, crashed into the rear of the truck launching it about 50 feet until it crashed into the tree (it's not as dramatic looking in the photo, but the truck's chassis was bent considerably right in the middle between the cab and the bed).
Meanwhile, the drunk driver's car careened off that truck and into the rear end of the same neighbor's SUV which was parked directly across the street in front of another neighbor's house (his nextdoor neighbor to the left in the photo).
Amazingly, the drunk driver had no injuries and ran off down the street after the accident.
Truned out that he lived just down the street and had gone home, changed his clothes and then returned to the scene, claiming it was his cousin who was driving the car.
The police arrived, didn't buy his story (the neighbors across the street saw him run from the scene), handcuffed him and hauled him off.
The amazing part is that I had a car parked in my driveway and one parked in the street directly in front of my house. The truck in the photo was parked directly behind the car in the street about 30 feet in back of it.
Somehow, when the truck was launched, it went at an angle such that it went right between my two cars even though there was less than a foot of clearance to either side.
The somewhat scary part is that I was out standing in front of that same truck a couple of hours earlier while raking up some leaves.
Crazy night.
se
Oh...
And for those into things such as Divine intervention and whatnot, here's a bit better image of the inside of the truck's cab. Note the object hanging from the rearview mirror.
se
And for those into things such as Divine intervention and whatnot, here's a bit better image of the inside of the truck's cab. Note the object hanging from the rearview mirror.
An externally hosted image should be here but it was not working when we last tested it.
se
fdegrove said:
Yup. Didn't appear to be a scrach on him. Well, before the cops got there anyway.
Juuuuuuuuuuuust kidding!
[Luckilly you got away with so little damage....Gosh...
Cheers and sympathies,
Thanks. The only property "damage" was a 6 foot skid mark on the grass and a bit of sap oozing from the mullberry tree.
se
fdegrove said:
You can if you'd like. I already EMailed him back on the 22nd but haven't had any reply yet. Though he's probably been on holiday all week.
I told him of John's measurements and that you had said you'd had him verify them at a customer's and van den Hul's request and asked if he'd care to share his test setup so that we could attempt to duplicate his results.
se
OK, no jokes about egg-nog and Asians.
I was watching a car wreck, too, the last game of the season for the '49ers. The only thing that saved the day was the sweet sound of my new preamp- passive, using the Jensen 11P-1s and an Alps Black Beauty pot. You could hear every bounce of the fumbled ball.
I was watching a car wreck, too, the last game of the season for the '49ers. The only thing that saved the day was the sweet sound of my new preamp- passive, using the Jensen 11P-1s and an Alps Black Beauty pot. You could hear every bounce of the fumbled ball.
Hi,
Hmmm...I don't think he was aware of John Curls' measurements at that time, neither did I ask him to veryfy anyone elses' measurements.
I did ask him several related questions on behalf of my company's customers amongst which VdH (indirectly) and Deskadel.
This is the kind of confusion I wanted to avoid in the first place and knowing him as I do he won't ever reply to that e-mail.
Don't take offense, that's just how I know him.
Anyway, I'll try to reach him at home, I was just trying to find out if you could or wish to make a list of target QQ.
Cheers,
Hmmm...I don't think he was aware of John Curls' measurements at that time, neither did I ask him to veryfy anyone elses' measurements.
I did ask him several related questions on behalf of my company's customers amongst which VdH (indirectly) and Deskadel.
This is the kind of confusion I wanted to avoid in the first place and knowing him as I do he won't ever reply to that e-mail.
Don't take offense, that's just how I know him.
Anyway, I'll try to reach him at home, I was just trying to find out if you could or wish to make a list of target QQ.
Cheers,
fdegrove said:
I just quoted him what you had said previously:
Rest assured, I trust you and your [John Curl's] results as they were cross checked at the Leuven University by Dr. De Ceuninck on my (customer request) and A.J. vdH's request.
I'd just like to know what sort of distortion measurements he'd made and what his test conditions were.
se
Originally posted by Steve Eddy
It should be kept in mind that these measurements are NOT an attempt to quantify heard differences in cables.
These measurements are an attempt to reproduce the distortion measurements that John Curl has been doing in order to determine whether or not the distortion he's been measuring is being produced by the cables themselves.
Bruno's posting...
Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing........
Ok, either way we are between us trying to measure what we (that is, those of us who are publically admitting to hearing systems differences due to change of cables) are hearing, and nail down at least some of the reasons.
I have normal standard mass produced interconnnect RCA cable assemblies that all sound different in a given system, or more correctly cause a given system to sound different according which cable is in use.
It is (ought to be) a perfect given that cable electrical values (LCR) in an unbalanced system can cause differing behaviours between interconnected equipment.
Bruno suggests unbalanced system cable microphonics and shield return conductor resistance, and I agree that these are two distortion effects in addition to the expected standard LCR caused behaviours.
Others are suggesting micro-diode step conduction behaviours in wires as another mechanism.
I observe strong and permanent directionality characteristics in a particular coaxial audio cable assembly.
On the other hand Frank suggests non permanent bias in wires.
(Both of us are waiting for Steves cables to arrive so that we can take a close listen and voice our findings).
Yes, test methodologies is the question here.
Eric.
It should be kept in mind that these measurements are NOT an attempt to quantify heard differences in cables.
These measurements are an attempt to reproduce the distortion measurements that John Curl has been doing in order to determine whether or not the distortion he's been measuring is being produced by the cables themselves.
Bruno's posting...
Recently I've done a collection of measurements on interconnect cables to see what I could find that would explain the sonic differences that many people, including myself, have grown accustomed to hearing........
Ok, either way we are between us trying to measure what we (that is, those of us who are publically admitting to hearing systems differences due to change of cables) are hearing, and nail down at least some of the reasons.
I have normal standard mass produced interconnnect RCA cable assemblies that all sound different in a given system, or more correctly cause a given system to sound different according which cable is in use.
It is (ought to be) a perfect given that cable electrical values (LCR) in an unbalanced system can cause differing behaviours between interconnected equipment.
Bruno suggests unbalanced system cable microphonics and shield return conductor resistance, and I agree that these are two distortion effects in addition to the expected standard LCR caused behaviours.
Others are suggesting micro-diode step conduction behaviours in wires as another mechanism.
I observe strong and permanent directionality characteristics in a particular coaxial audio cable assembly.
On the other hand Frank suggests non permanent bias in wires.
(Both of us are waiting for Steves cables to arrive so that we can take a close listen and voice our findings).
Yes, test methodologies is the question here.
Eric.
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