Hey, what about using twisted 300 or 450 ohm ladder line for speaker cable? I won't speculate on sonic effects except that the high characteristic impedance may be easier on amps that have cable problems.
The largest size I've seen is 14ga copper clad steel.
The largest size I've seen is 14ga copper clad steel.
Oxidation happens fairly fast. Especially in elevated temperatures. Are you you sure your Chinese wire in formed in an inert environment? if not, it is probably oxidated. We do a lot of eutectics and have to use forming gases, plasma cleaning, scrubbing of, yes, gold parts, etc.
I use quite a bit of stycast 2850 FT. Alumina filled epoxy, two part. But it's not a particularly strong material in tension or shear. Thin plates of it would not be a good structural member however.
jn
I've said it before and I know that SY will back me up on this one, no matter what filler you put in an engineered or thermoset plastic the heat transfer is terrible. I have done this with all types of fillers and aluminum flake and everything else you can think of. Each grain or metal oxide is encapsulated by the resin matrix and the heat transfer is always dominated by the polymer matrix, no way to overcome this fact. Until you have such a high loading that the matrix polymer fails to bond the filler it is always going to be a poor way to extract heat. I have had to have this argument so many times in the application of these materials in tooling applications for molding plastic parts and the horrid heat transfer and material failure modes.
The lasers are athermal in this application, I need to knock off about 20 C from Tmax at 85C from the FPGA's. I am going to use a thermal strap and tie it the the package wall. This is more for longevity and safety. I am just exploring. If not, I will co with extruded aluminum.
I know you were. I was just pointing out that with all this fretting over copper, even a cable made with ferromagnetic material which must have some amount of nonlinearity due to hysteresis can't even manage to poke it's head up above -145dB.
se
Interesting we have some amps in plastic rated at 150C continuous case temp.
I share your concerns, Richard - so for me multistrand is out, in every situation. Yes, no proof, but the sound has not suffered from this approach - flexibility could become an issue, so some care needs to be taken ...
Let me suggest an experiment. Take a very old piece of stranded speaker cable and grab about 1/2 of the strands at each end at random, that gives you about 1/2 the strands "broken" on the average. Then measure the voltage across it vs current and look for any anomolies.
Scott,
> Interesting we have some amps in plastic rated at 150C continuous case temp.
It is a question that I always wanted to ask a semiconductor device engineer.
There are many opinions here about how hot active devices should be allowed to work to without reliability risk.
And I am sure that they are more agressive in industrial applications than in "Hi-End" Audio.
For example, automotive electronics are rated at 80°C continuous (ambient, not junction).
I have also read a Toshiba Reliability Handbook which contains lifetime curves indicating no noticeable lifetime issues for junction temperatures of 100°C or below.
Are there any guidelines from AD for their customers or the public ?
Patrick
> Interesting we have some amps in plastic rated at 150C continuous case temp.
It is a question that I always wanted to ask a semiconductor device engineer.
There are many opinions here about how hot active devices should be allowed to work to without reliability risk.
And I am sure that they are more agressive in industrial applications than in "Hi-End" Audio.
For example, automotive electronics are rated at 80°C continuous (ambient, not junction).
I have also read a Toshiba Reliability Handbook which contains lifetime curves indicating no noticeable lifetime issues for junction temperatures of 100°C or below.
Are there any guidelines from AD for their customers or the public ?
Patrick
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Just woke up ---
Yes it does oxidize quickly. I know of at least one wire maker in Taiwan who had its entire raw wire order returned for oxidation..... turned out to have sat at the shipping docs for a couple weeks before customer recieved it.
There are cable companies who draw thier ultra pure copper wire in an inert atmosphere and use a X linked poly something insulation that makes the finished wire a bit stiff but retards oxidation greatly.
Its all real... is it relevant to you or to audio? You decide.
THx-RNMarsh
I'd like mine with some cheese on the side, please Mooly. 😀
One thing is certain - that Blowtorch preamp must have been a hell of a preamp if we're down to discussing the manufacturing differences and practices of cable manufacturers to do it justice.
It appears we need to ask the seller to show a certificate stating that the wire did not sit in some harbour warehouse before being shipped. And that we need, just in case, to cut the wire all along its length to make sure there are no broken strands. That's if we have strands, because we could have solid core cables.
Come on, gentlemen, the vast majority of us simply buy the cable they need, we do not make them. Do they sound the same? They don't, but that's hardly news when one can measure the RLC specifics of cables and see for himself that they are not the same.
And what about pure silver strand cables? What about the so called hybrid cables, such as my van den Hul mix of silver plated OFC copper and carbon fibre (as stated by the manufacturer)? What conditions must that carbon fibre satisfy for it to be good?
One thing is certain - that Blowtorch preamp must have been a hell of a preamp if we're down to discussing the manufacturing differences and practices of cable manufacturers to do it justice.
It appears we need to ask the seller to show a certificate stating that the wire did not sit in some harbour warehouse before being shipped. And that we need, just in case, to cut the wire all along its length to make sure there are no broken strands. That's if we have strands, because we could have solid core cables.
Come on, gentlemen, the vast majority of us simply buy the cable they need, we do not make them. Do they sound the same? They don't, but that's hardly news when one can measure the RLC specifics of cables and see for himself that they are not the same.
And what about pure silver strand cables? What about the so called hybrid cables, such as my van den Hul mix of silver plated OFC copper and carbon fibre (as stated by the manufacturer)? What conditions must that carbon fibre satisfy for it to be good?
For auto power mosfets (ABS, power steering, engine management applications) they are characterized for a peak repetitive junction temperature of 175 deg C.
Quite a tough environment. 4 lots of 77 usualy sorts the wheat from the chaff.
175°C is not long term useage.
I want to know what ist the industrial guideline is for continuous use with minimum 7 years lifetime.
Patrick
I want to know what ist the industrial guideline is for continuous use with minimum 7 years lifetime.
Patrick
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