That will be confusing for me then, as I wear both hats. I already have to remember whether to use 'i' or 'j' when speaking of complex numbers.scott wurcer said:
That is physics. Everything else about cable directionality is not even philately.john curl said:
Yes, I'm sure suppliers to defence and medical systems (not to mention LIGO) make sure that they get their cable directionality right.
I had a professor that was a microwave old timer. I asked why they use noise temperature rather than noise figure and he said, "To keep the riff raff out".
I have to give up here. The varnish changes (dries) in the container while being applied, so no two spots will ever be coated with the exact same varnish. I need to switch to metal horns and powdercoat them. But then the horns might remember being charged with static to attract and hold the powder. The horns might remember that charge forever and even pass it on to one of the most crucial parts of the system. The cables.
Which then brings me back to post #12373.
YouTube
I don't have a guitar. I don't have a guitar cable. I don't know whether some guitar cables are deliberately built in an asymmetric fashion (e.g. shield only connected at one end). I don't trust my ears. I do trust physics.Max Headroom said:
Noise figure becomes less useful when antenna temperatures are below room temperature. I still get confused between noise factor and noise figure, especially when some people use one but call it the other.scott wurcer said:
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I was a very wise Greek that said, "You can never step in the same river twice".
All guitar cables I've ever made, seen, heard of or used are coax. There's a billion things that make a difference in sound and a difference in how the musician might feel about playing which changes his playing and sound. I never heard any difference in plugging in a cable one way or the other. But I don't care and my guitar and pickups are not good enough, the cables I've used are not resolving enough and all the amplifiers I've ever played over lacked magic goop, so please disregard these statements.
It should be noted that the monster cables that I've got the ones in the pic above sound terrible. They add a muffled sound to the highs and vocals. This is with comparing them to homemade RG58 50 ohm cables and RG6 75 ohm cables that I've been using as my home bread and butter for a few months. The sound change is incredibly slight however and took me a while to spot the problem.
The RCA connectors middle pins on the monster cables are larger than standard aswell and are a pain in the **** to insert and remove into an RCA female connector and don't do a good enough job in my opinion of clamping down on the outer shield part of the socket which may be the contributing factor in the sound quality change.
Don't know what the monster cables are made from or how they're made and I don't really care, will probably be tossing them in the bin. Might end up taking some pics before I do though.
The RCA connectors middle pins on the monster cables are larger than standard aswell and are a pain in the **** to insert and remove into an RCA female connector and don't do a good enough job in my opinion of clamping down on the outer shield part of the socket which may be the contributing factor in the sound quality change.
Don't know what the monster cables are made from or how they're made and I don't really care, will probably be tossing them in the bin. Might end up taking some pics before I do though.
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That is a question that I've been asking myself for years but I'm not all knowing so have never answered it myself. Sure AF isn't RF but the typical opinion is that AF is such a low frequency that impedance doesn't matter. Its as close to DC so therefore it won't matter, the wavelength is so long that it won't matter. (Citation needed)
Then again in a passive crossover circuit the impedance matters a lot?
However Digital circuits such as SPDIF, thats a different matter and I do only use 75 ohm coaxial cables for those purposes. But for AF a 50 ohm RG58 is much easier to solder and terminate with RCA connectors and its a lot more flexible than RG6. I use Rojone when available and Belden when not.
I mean if there is RF on the cable that is carrying AF then wouldn't you want it to be properly matched to the secondary device so its better filtered out by the receiving circuit's filtering stages? That is a question that I've been waiting to be answered for a while now.
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They do, but only when the cable is long enough for this to matter (few km and up?) and special steps have been taken to ensure that the cable has an impedance.HarryY said:
At audio frequencies (unlike RF) a cable does not have 'an impedance'. It has an impedance which is not resistive and varies with frequency. This is because characteristic impedance is dominated by series resistance and shunt capacitance, so Z=sqrt(R/jwC). Propagation speed also varies with frequency. Fortunately this doesn't matter if the cable is short. It is simply a connection, a piece of wire forming a trivial part of a potential divider. It adds a little shunt capacitance, which has to be driven by the source.
Longer audio cables get into trouble; different frequencies travel at different speeds and termination was difficult too. Oliver Heaviside solved this problem, although it took him a while to convince the British Post Office that his solution (correct but counter-intuitive for the poorly trained engineers of the day) worked. You add inductance so that the series element is dominated by it (as in an RF cable) rather than resistance. Then cable impedance becomes sqrt(L/C) and everything travels at the same speed. The downside is some reduction in bandwidth, as the cable becomes a low pass filter.
There are a few 'special' audiophile cables which do the same trick (putting some inductance in the connectors) and charge a lot of money for something so simple. People may be happy to pay for the nice story and warm glow this gives; electrically it is quite unnecessary for a short domestic interconnect.
I realize that at audio it probably doesn't matter but I would tend to believe that impedance
would matter Far more than any kind of directionality some may believe a cable has.
Yes I do realize for long distances impedance does get factored in my competent engineers,
but for home audio it seems many "Audiophiles" don't know about impedance.
would matter Far more than any kind of directionality some may believe a cable has.
Yes I do realize for long distances impedance does get factored in my competent engineers,
but for home audio it seems many "Audiophiles" don't know about impedance.
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Most consumers do not care about the differences, but in order to get optimum performance, it is necessary. The audio range is where the impedance of cables change from being very high to very low. Somewhat like a capacitor in parallel with a resistor. But when you do the same on the input impedance of your equipment, you get a better match. It is possible for DIY projects but not commercial designs.
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