Now, likely everyone read a comment completely
.From first post, I write I use signal generator with sweep function and terminated the other end of cable using 75 Ohm resistor because 75 Ohm is standard impedance input for video signal. The 75 Ohm resistor connect to spectrum analyzer. In the spectrum analyzer you can see the bandwidth.
I hope you can imagine it although my English is not good.
We must bought complete interconnect cable with RCA jack from supplier for product accessories. Sometime we bought from the market for testing. I made sure the cables can be use without suffering the bandwidth.
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Find ICs that have the chip mounted on a thermal pad, I'm Shure it could be controlled enough, not to be a problem, if it is a problem.
RCA introduces a small impedance blip, which will affect VHF and up. The standard connector for video is 75R BNC, which is constant impedance and good to a few GHz.
The cable you bought must have been very poorly made, and perhaps not really RG58 at all. How long was it? Was it made in China, by any chance? Maybe Chinese ohms are a bit like Chinese watts!
Is it possible that the cable was meant for audio interconnect duty and included a ferrite RF suppressor inside the plug? That might measure poorly for video.
The cable you bought must have been very poorly made, and perhaps not really RG58 at all. How long was it? Was it made in China, by any chance? Maybe Chinese ohms are a bit like Chinese watts!
Is it possible that the cable was meant for audio interconnect duty and included a ferrite RF suppressor inside the plug? That might measure poorly for video.
For standard measurement I always use BNC connector and coax cable. Almost every instrument using BNC connector too.
I don't know where they came from. Usually it consist 3 cable, 1 for video (yellow RCA), and and 2 for audio (Red and white RCA).
STEALTH audio cables
Some carbon cables, complete with 6 moons revue:
6moons audio reviews: Stealth Nanofiber & Metacarbon
and here it gets even better, military/space secrets getting into the hands of Audio designers, what a load of B*******
http://www.6moons.com/audioreviews/stealth/indra.htm
What is your blessing for John, more misdirection from real science and engineering!!!
A cable is there to connect two bits of equipment together, there is only Audiophoolery where cables become a thing of fetish and worship, and the amount of secret military stuff that gets into the audio world is incredible, why bother with getting security clearance, when you can get all the info you need from true Audiophile manufacturers (a dedicated panel of listening experts employing aerospace engineers on a night to do the design work).......
Isn't RG58 50ohm cable and RG59 75ohm
Some carbon cables, complete with 6 moons revue:
6moons audio reviews: Stealth Nanofiber & Metacarbon
and here it gets even better, military/space secrets getting into the hands of Audio designers, what a load of B*******
http://www.6moons.com/audioreviews/stealth/indra.htm
What is your blessing for John, more misdirection from real science and engineering!!!
A cable is there to connect two bits of equipment together, there is only Audiophoolery where cables become a thing of fetish and worship, and the amount of secret military stuff that gets into the audio world is incredible, why bother with getting security clearance, when you can get all the info you need from true Audiophile manufacturers (a dedicated panel of listening experts employing aerospace engineers on a night to do the design work).......
Isn't RG58 50ohm cable and RG59 75ohm
Off topic but still in lounge, this weekend one of my golden eared friends was pontificating on why my planar tweeters were harsh on his ears , and he could clearly hear a 25,000 hertz resonance which was bothersome and beyond my mortal hearing.
Had to tell him then I'd been expecting his Pavlovian response to any tweeter not made of silk.
The tweeters were not turned on on the actively biamped system.
Somehow he was hearing 25,000 hz from a SEAS 8" TV21 tilted up to beam away any breakup modes.
Subjectively, we may all hear what we want, or at least expect to.
Had to tell him then I'd been expecting his Pavlovian response to any tweeter not made of silk.
The tweeters were not turned on on the actively biamped system.
Somehow he was hearing 25,000 hz from a SEAS 8" TV21 tilted up to beam away any breakup modes.
Subjectively, we may all hear what we want, or at least expect to.
Just shows, the 25kHz resonance was so bad it even appeared when the tweeter was disconnected
You can test to your friend if he can hear single tone of 25 kHz or not. I think only few people can do.
But many people can hear the "intermodulation" of high frequency with low frequency.
I can hear the "unusually" sound of my pre-amp, although some of my family can not hear what wrong. When I connect my pre-amp to oscilloscope, it show small oscillation around 100kHz. Can I hear single tone of 100kHz? Of course not!
One other question someone could ask: did the generator have the usual 50 ohms source impedance? Did the spectrum analyzer have the customary 50 ohms input impedance?
Jan
The red white and yellow cables that often come with lower price equipment will do the job, just, but they will be cut back to the bones cost wise. I find that often the shielding is the part that suffers the most, often these cheepo cables will happily pick up any stray noise and with analogue video signals it is very visible...
I am using a cheepo VGA cable at the moment (no digital inputs left and someone has pinched my decent VGA) the picture is OK, but I am getting noise pick up. But used for digital signal transmission there should be no real problem, and the cheepo DVI cable that came with the monitors is fine (no visible noise).
The original reference was to video signals 15 years ago, that were more than likely composite video, where the back porch and other sync signals could get mashed up by noise, but digital wise the cable should be good for many MHz.
The original reference was to video signals 15 years ago, that were more than likely composite video, where the back porch and other sync signals could get mashed up by noise, but digital wise the cable should be good for many MHz.
I always avoid 6Moons, it's one of the worst audio websites ever made.
Yes the only job for a cable is to transfer the signal from A to B unaltered. Funny how some people want them to do 100 other things instead like changing the frequency response which is the job of tone controls.
Without having read this entire thread, I'll throw in my two cents worth. My background in engineering at Tektronix and Dolby labs may qualify me to mouth off here. I've also been a hard-core audio engineer hobbyist since grade school in the 1960's.
Fancy speaker wire is arguably better theoretically, but the amount better is hard to measure on the worlds most sensitive and sophisticated test equipment. Adding an ohm in series with a random 8 ohm bookshelf speaker will throw away about 12% of the power (about one dB), but may also cause the passive crossover to become more accurate (50/50 chance). Passive crossovers are rarely very accurate. When you consider all the other compromises any speaker system has to deal with, any problem a wire could have is suddenly ridiculously small. I buy 16AWG AC line cord at any hardware store, solder it to gold alloy plated connectors (usually Banana connectors) and consider it just as good as the Jenlabs $14000 speaker wire, and any other "speaker wires". Connectors, or how the wire is attached to the connectors is often a weak link, but not likely the wire itself. The idea that speaker wires can act as antennas and bring Rf into the feedback circuits of some power amplifiers is a bit far fetched. Poweramp output impedances are very low and will short out this energy unless the poweramp design is poor. In the case of a no feedback tube amp, this could be arguable, but the feedback itself could be designed to reject Rf (mine is).
Same story with inter-connect cables. If they are judged to have too much capacitance, then maybe the source has an unusually high output impedance, or is unstable driving even the slightest bit of capacitance, or the run too long. If you're going 3 ft., don't sweat it. Gold alloy connectors are likely better over time, but I've never seen this be an issue. If you're going across a room you might want to consider XLR's and a differential signal to minimize hum, if that's a problem.
Tone control issues make me laugh just as much as wire issues. The most expensive preamps in the world all seem to lack tone controls... Say what?! They presume that program material is mixed perfectly, and takes into account your listening room acoustics, your speaker frequency response and dispersion pattern, and even your loudness level (can you say Fletcher-Munson?). People knew back in the 1920's that accuracy and enjoyability was clearly improved by the use of tone controls. Why are some people not discovering that for themselves now days? Yes there are some tone control circuits that are poorly designed, but the Baxandall has been around forever and is good. I built a 4 section Baxandall and am very happy with it. It's completely ridiculous to not have decent tone controls.
A friend of mine swears that capacitors make a huge difference. Yet nobody can show this on any test equipment. The measurable distortions are orders of magnitude less than virtually any amplifier I've ever heard of. I use low cost polypropylene dielectrics, or poly styrenes, and consider those as good as anything. If I have to put an electrolytic in the signal path, I make sure it's biased properly if it's a polarized type (Behringer didn't), I might put a 0.1uF polyprop across it so its impedance stays low to a much higher frequency, but I doubt if I need to. Putting power supply bypass caps (0.1uF - value not critical) very near opamps, or high feedback circuits of any kind is very important, otherwise phase margin is less predictable.
Resistors... the above friend of mine ( a very hard core tube guy) swears that various expensive carbon comp resistors sound better than metal film resistors. He claims that metal film resistors sound "metalic"... Metal films are lower noise. Carbon comps are hissy. Hiss will change your perception overall, and perhaps make some people think the sound is less "metalic".
Moving coil cartridges better than moving metal types? Not necessarily unless they track grooves better. Since they have a much lower output impedance than MM, they aren't significantly sensitive to loading capacitance. MM's are very sensitive to loading capacitance, and the engineers design them based on a guess/prediction of what the typical cable capacitance will be, going from the turntable to the preamp. As far as I have been able to see, there really is no standard turntable cable capacitance or phono preamp input capacitance. When the loading capacitance is wrong, you get either a spiked up top end frequency response, or a prematurely rolled off freq. resp. The difference is pretty significant. You'd have to put on a test record, and look at pink noise or sine sweeps on some variation of a spectrum analyzer, and then adjust the loading capacitance for the flattest frequency response. How many people do I know who have done that? Zero.
Legitimate concerns are any connectors, switches, pots, proper loadings, handling of potential RF going into high feedback circuits that can't handle Rf energy elegantly. I use gold contact sealed switches and/or relays. I use Alpha pots because you can spray clean them. Every sealed pot I've ever used got noisy eventually, and there was no way to clean them. Some preamps and poweramps (or any other signal processors) go unstable when driving a reactive load. A good design will have a buildout resistor on it's output that limits how reactive the load will look to the circuit driving the load. Linkwitz uses 200ohms on the output of every opamp that drives the outer world. So do I. Good poweramps all have output chokes across a very small (maybe 10 ohm) resistor. the coil shorts out the resistor at audio frequencies, but becomes inductive at supersonic frequencies, to reduce the effects of typical capacitance at those frequencies. Any preamp, powermap or signal processor should have Rf filtering on both the signal input and in the powersupply, since it can cause slewing, I.M. distortion generation, and even blowing of high feedback amplifers. Now days with digital sources and all the Rf in the air, it seems even more necessary.
Are tubes better sounding than transistors? In a guitar amp where you might want to overdrive them for the distortion effect, yes. In a Hi-Fi amp, yes too, but the difference is usually very small, and not always for the reasons most people think.
A good tube circuit will distort with a more natural distortion spectrum, more like how the human ear distorts. The second harmonic will usually dominate, which enhances pretty much any sound, since it's the same note one octave higher. All other harmonics are hit and miss as to whether or not they make the music sound better. The more higher order harmonic distortion products you have, the more dissonance you'll have. Most tube circuits have a faster rolloff of their distortion products, which is desirable.
Tubes being much more linear than transistors don't need to make use of much if any negative feedback. Feedback usually cleans up the distortion of an amp at 1kHZ with a sinewave test signal. It also makes an amp more sensitive to load reactance, and typically becomes inoperable at supersonic frequencies. The whole phase margin thing becomes a big issue.
Bottom line: these days any well designed transistor poweramp should sound dam close to just as good as any tube amp in a Hi-Fi system. If there's a noticable difference, it's probably not about tubes vs. transistors. Many tube amps are fun art objects, and are nostalgic for many of us. Transistor amps are more practical. I have 12 poweramps in my main system (a half circle of surround sound, with the center speaker being a bi-amp'd Polk style stereo hologram). Doing all of that with tubes would take up more space than I have, plus my breaker box might have problems with the amount of current draw. In my guitar amps, which I researched, designed and built myself, I think tubes have a lot to do with the great sound I get, both clean and when overdriven into distortion. My guitar amp circuits have no feedback anywhere. Tubes distortion seems inaudible until I crank up the gains enough to cause noticable distortion, at which point I get the Eric Clapton sound. Most transistor guitar amps I've heard when overdriven sound horrible; like fingernails on a blackboard.
What have I forgotten? Listening room acoustics play a huge part in the sound. How a speaker interacts with room acoustics is arguably the weak link in any decent system. Speakers usually interact better when they are positioned along the long wall of the room, so they can be further from any room boundaries (walls generally). Putting damping material (cheap non-flamable foam rubber is a good choice) in all corners of the room (wherever practical) is a substantial improvement. Using woofer towers (my opinion) or dipole woofers (Linkwitz's opinion) is likely to reduce boominess due to room acoustic problems.
Well, those are the major issues I can think of right now. Hope this is helpful.
Fancy speaker wire is arguably better theoretically, but the amount better is hard to measure on the worlds most sensitive and sophisticated test equipment. Adding an ohm in series with a random 8 ohm bookshelf speaker will throw away about 12% of the power (about one dB), but may also cause the passive crossover to become more accurate (50/50 chance). Passive crossovers are rarely very accurate. When you consider all the other compromises any speaker system has to deal with, any problem a wire could have is suddenly ridiculously small. I buy 16AWG AC line cord at any hardware store, solder it to gold alloy plated connectors (usually Banana connectors) and consider it just as good as the Jenlabs $14000 speaker wire, and any other "speaker wires". Connectors, or how the wire is attached to the connectors is often a weak link, but not likely the wire itself. The idea that speaker wires can act as antennas and bring Rf into the feedback circuits of some power amplifiers is a bit far fetched. Poweramp output impedances are very low and will short out this energy unless the poweramp design is poor. In the case of a no feedback tube amp, this could be arguable, but the feedback itself could be designed to reject Rf (mine is).
Same story with inter-connect cables. If they are judged to have too much capacitance, then maybe the source has an unusually high output impedance, or is unstable driving even the slightest bit of capacitance, or the run too long. If you're going 3 ft., don't sweat it. Gold alloy connectors are likely better over time, but I've never seen this be an issue. If you're going across a room you might want to consider XLR's and a differential signal to minimize hum, if that's a problem.
Tone control issues make me laugh just as much as wire issues. The most expensive preamps in the world all seem to lack tone controls... Say what?! They presume that program material is mixed perfectly, and takes into account your listening room acoustics, your speaker frequency response and dispersion pattern, and even your loudness level (can you say Fletcher-Munson?). People knew back in the 1920's that accuracy and enjoyability was clearly improved by the use of tone controls. Why are some people not discovering that for themselves now days? Yes there are some tone control circuits that are poorly designed, but the Baxandall has been around forever and is good. I built a 4 section Baxandall and am very happy with it. It's completely ridiculous to not have decent tone controls.
A friend of mine swears that capacitors make a huge difference. Yet nobody can show this on any test equipment. The measurable distortions are orders of magnitude less than virtually any amplifier I've ever heard of. I use low cost polypropylene dielectrics, or poly styrenes, and consider those as good as anything. If I have to put an electrolytic in the signal path, I make sure it's biased properly if it's a polarized type (Behringer didn't), I might put a 0.1uF polyprop across it so its impedance stays low to a much higher frequency, but I doubt if I need to. Putting power supply bypass caps (0.1uF - value not critical) very near opamps, or high feedback circuits of any kind is very important, otherwise phase margin is less predictable.
Resistors... the above friend of mine ( a very hard core tube guy) swears that various expensive carbon comp resistors sound better than metal film resistors. He claims that metal film resistors sound "metalic"... Metal films are lower noise. Carbon comps are hissy. Hiss will change your perception overall, and perhaps make some people think the sound is less "metalic".
Moving coil cartridges better than moving metal types? Not necessarily unless they track grooves better. Since they have a much lower output impedance than MM, they aren't significantly sensitive to loading capacitance. MM's are very sensitive to loading capacitance, and the engineers design them based on a guess/prediction of what the typical cable capacitance will be, going from the turntable to the preamp. As far as I have been able to see, there really is no standard turntable cable capacitance or phono preamp input capacitance. When the loading capacitance is wrong, you get either a spiked up top end frequency response, or a prematurely rolled off freq. resp. The difference is pretty significant. You'd have to put on a test record, and look at pink noise or sine sweeps on some variation of a spectrum analyzer, and then adjust the loading capacitance for the flattest frequency response. How many people do I know who have done that? Zero.
Legitimate concerns are any connectors, switches, pots, proper loadings, handling of potential RF going into high feedback circuits that can't handle Rf energy elegantly. I use gold contact sealed switches and/or relays. I use Alpha pots because you can spray clean them. Every sealed pot I've ever used got noisy eventually, and there was no way to clean them. Some preamps and poweramps (or any other signal processors) go unstable when driving a reactive load. A good design will have a buildout resistor on it's output that limits how reactive the load will look to the circuit driving the load. Linkwitz uses 200ohms on the output of every opamp that drives the outer world. So do I. Good poweramps all have output chokes across a very small (maybe 10 ohm) resistor. the coil shorts out the resistor at audio frequencies, but becomes inductive at supersonic frequencies, to reduce the effects of typical capacitance at those frequencies. Any preamp, powermap or signal processor should have Rf filtering on both the signal input and in the powersupply, since it can cause slewing, I.M. distortion generation, and even blowing of high feedback amplifers. Now days with digital sources and all the Rf in the air, it seems even more necessary.
Are tubes better sounding than transistors? In a guitar amp where you might want to overdrive them for the distortion effect, yes. In a Hi-Fi amp, yes too, but the difference is usually very small, and not always for the reasons most people think.
A good tube circuit will distort with a more natural distortion spectrum, more like how the human ear distorts. The second harmonic will usually dominate, which enhances pretty much any sound, since it's the same note one octave higher. All other harmonics are hit and miss as to whether or not they make the music sound better. The more higher order harmonic distortion products you have, the more dissonance you'll have. Most tube circuits have a faster rolloff of their distortion products, which is desirable.
Tubes being much more linear than transistors don't need to make use of much if any negative feedback. Feedback usually cleans up the distortion of an amp at 1kHZ with a sinewave test signal. It also makes an amp more sensitive to load reactance, and typically becomes inoperable at supersonic frequencies. The whole phase margin thing becomes a big issue.
Bottom line: these days any well designed transistor poweramp should sound dam close to just as good as any tube amp in a Hi-Fi system. If there's a noticable difference, it's probably not about tubes vs. transistors. Many tube amps are fun art objects, and are nostalgic for many of us. Transistor amps are more practical. I have 12 poweramps in my main system (a half circle of surround sound, with the center speaker being a bi-amp'd Polk style stereo hologram). Doing all of that with tubes would take up more space than I have, plus my breaker box might have problems with the amount of current draw. In my guitar amps, which I researched, designed and built myself, I think tubes have a lot to do with the great sound I get, both clean and when overdriven into distortion. My guitar amp circuits have no feedback anywhere. Tubes distortion seems inaudible until I crank up the gains enough to cause noticable distortion, at which point I get the Eric Clapton sound. Most transistor guitar amps I've heard when overdriven sound horrible; like fingernails on a blackboard.
What have I forgotten? Listening room acoustics play a huge part in the sound. How a speaker interacts with room acoustics is arguably the weak link in any decent system. Speakers usually interact better when they are positioned along the long wall of the room, so they can be further from any room boundaries (walls generally). Putting damping material (cheap non-flamable foam rubber is a good choice) in all corners of the room (wherever practical) is a substantial improvement. Using woofer towers (my opinion) or dipole woofers (Linkwitz's opinion) is likely to reduce boominess due to room acoustic problems.
Well, those are the major issues I can think of right now. Hope this is helpful.
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Why is this guy even continuing a review when he states the $3000 1 metre
cable is noisy and soft on top ?!
And how far does one wish to veer away from the "sound" of the wiring used by the recording engineers to monitor their recording.
And how does a team who sweated the design and component choices in a pre amp, amp or any other audio device built for quality and a target price point feel about a piece of wire being retailed at that price when it doesn't deliver the same signal as was input.
That ain't fidelity.
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