I wouldn't mind a shot at it. I've got a set of Monster Cables - not nearly as good as some of my home brew cables😉 Of course, if we're talking trying to hear the difference using MP3 through Bose Minicubes it may be a hopeless effort.
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When one is talking about impedance discontinuities (or miss-matches) for digital transmission/reception, I can see where reversing a cable might make some difference. However if the discontinuity is that bad, then one needs to replace the cable with a proper one any way.
Going from an impedance matching requirement for digital transmission to reversing a segment of twin lead speaker wire it a far streach of the imagination.
Even if there were a kink in the speaker wire at one end (Short of causing a break int he conductors), there would not be enough effect on the electrical characteristics of the wire to produce a detectable difference in signal propoigation at audio frequency.
Going from an impedance matching requirement for digital transmission to reversing a segment of twin lead speaker wire it a far streach of the imagination.
Even if there were a kink in the speaker wire at one end (Short of causing a break int he conductors), there would not be enough effect on the electrical characteristics of the wire to produce a detectable difference in signal propoigation at audio frequency.
There is a slight difference shown in the sims, these discontinuity's are what allow us to find breaks and problems in cables and get the distance, great for when the cable is buried. When cable in the UK went digital a lot of cables from the cabs to peoples houses had to be replaced because when a line got cut (usually by an overzealous gardener) the fitters (paid by the job) would splice the cable instead of pulling a new one like they were supposed to.
But looking at some real cables where I am working at the moment, there were no differences and I would think it safe to say that a cable run from a good manufacturer is going to be spot on.
I loved the bit where changing the cable direction removed the digital harshness, another phenomena I don't get as its analogue that comes out, the only explanation I for this I believe is excess noise, usually by following some of the more way out modding beliefs such as changing small SMD decouplers for nice film type leaded ones on the digital sections🙂
But looking at some real cables where I am working at the moment, there were no differences and I would think it safe to say that a cable run from a good manufacturer is going to be spot on.
I loved the bit where changing the cable direction removed the digital harshness, another phenomena I don't get as its analogue that comes out, the only explanation I for this I believe is excess noise, usually by following some of the more way out modding beliefs such as changing small SMD decouplers for nice film type leaded ones on the digital sections🙂
Some of the mods I've seen pictures of had enough lead inductance to obviate any advantage the film cap might have had as a decoupling cap at high frequency.
Only in this new world with all of the knowledge in the world at our fingertips have so many looked so foolish, with no reason at all to be ignorant.
So true!
What I also find interesting is that apparently there is no such thing as 'free information'. Even with all the information in the world basically for grabs for free on the 'net, you still have to expend effort to separate the chaff from the corn, the valid, genuine knowledge from the BS, the hoaxes, the sheer mass of misinformation and misleading marketing. Hi-end audio is by no means the only field where this is rampant.
So, there's no way around study and self-learning, despite the 'free knowledge'.
Must be another law of nature.
jan
Exactly, X7R MLCC in the smallest package size available for a given value next to a devices power pins is best, especially for digital devices, and for analogue devices with high slew rates, they forget that in decoupling inductance is the killer, not absolute capacitor value or dielectric type. Though for oscillator's a very low value COG next to the pins has some advantages. Some of the other dielectrics are ok, but especially with digital, size is everything to minimise parasitic inductance.
Just been watching a BBC2 (I think) series on secrets of shopkeepers (marketing) and even for the most basic things twisting the truth and reality seems to be the norm. There is also a willingness to believe things both on TV and the internet, my beloved Wife's dressing table top is proof of this!!!!!!
I do believe Bill Hicks view on marketing is quite true...
Based on Jan's advice already in this thread "But wouldn't it be more intelligent to first check whether there is an audible difference".
Is there an audible difference between using smd & a couple of mm s of leaded cap?
What is this audible difference?
What advice...
I am on about the proper decoupling of digital ICs and decoupling in general, how it should be done, this is not based on myths this is based on physics and engineering, if you are going to decouple a digital IC you use the smallest case size SMD capacitor next to the devices supply pins, larger values and case sizes acting as reservoir devices can be further away form the IC, that is the ONLY way to correctly decouple digital ICs....
You cannot listen to decouplers and form an opinion, and yes a couple of mm of lead makes the decoupling device useless, in fact it becomes an inductor.
it would be more intelligent to read up on power supply integrity and decoupling fo digital devices, what does a decoupler do...it provides the instantaneous power required when a digital IC switches...
When a digital IC switches (changes state) the instantaneous power comes from the on die capacitance, second is the power/ground plane capacitance, then the small case low value caps, then the next size and value up and so on until finally the power supply reacts. Any inductance will slow down the current delivery which has serious consequences....
leaded 0.1uF capacitors are useless for decoupling todays digital devices....
#4841 I presume, we are talking something completely different here....
I am on about the proper decoupling of digital ICs and decoupling in general, how it should be done, this is not based on myths this is based on physics and engineering, if you are going to decouple a digital IC you use the smallest case size SMD capacitor next to the devices supply pins, larger values and case sizes acting as reservoir devices can be further away form the IC, that is the ONLY way to correctly decouple digital ICs....
You cannot listen to decouplers and form an opinion, and yes a couple of mm of lead makes the decoupling device useless, in fact it becomes an inductor.
it would be more intelligent to read up on power supply integrity and decoupling fo digital devices, what does a decoupler do...it provides the instantaneous power required when a digital IC switches...
When a digital IC switches (changes state) the instantaneous power comes from the on die capacitance, second is the power/ground plane capacitance, then the small case low value caps, then the next size and value up and so on until finally the power supply reacts. Any inductance will slow down the current delivery which has serious consequences....
leaded 0.1uF capacitors are useless for decoupling todays digital devices....
#4841 I presume, we are talking something completely different here....
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On the digital side you bad decoupling practice will lead to power supply and ground noise being increased, in a DAC this is likely to affect the analogue signal going out so will affect fidelity. Doing the decoupling correctly will give you cleaner power. The noise generated by digital circuitry (SSN, under specified SMPS's in PC's etc) doesn't effect the digital circuitry in the same way it affects the analogue, so keeping it to a minimum is critical to getting the best analogue waveform out of a DAC (not just audio). Texas/Analog etc have a good app notes regarding this sort of thing, one example:
http://www.ti.com/lit/an/slaa510/slaa510.pdf
As to audibility, yes it can be if not done right, especially noticeable on headphones, it all adds to the noise floor.
http://www.ti.com/lit/an/slaa510/slaa510.pdf
As to audibility, yes it can be if not done right, especially noticeable on headphones, it all adds to the noise floor.
THE DIAGNOSIS AND SOLUTION OF JITTER-RELATED PROBLEMS IN DIGITAL AUDIO SYSTEMS
Julian Dunn* and Ian Dennis, Prism Sound Limited Presented at AES 96th Convention, February 1994
© Julian Dunn 1994
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.68.2092&rep=rep1&type=pdf
"CONCLUSION
Several tools have been developed to measure the digital audio interface parameters discussed in [2], including a jitter modulator to produce known and controllable amounts of jitter so that measurements of jitter transfer function and jitter tolerance can be made. Mathematical models to relate sampling jitter levels and resultant distortion products have been refined and measurements have been made using a wide dynamic range spectrum analysis tool. Results indicate a good correspondence. The jitter attenuation recorded by results from some of the converters indicate that, as well as being impractical, it is not necessary to specify maximum interface jitter levels commensurate with sampling jitter levels necessary to ensure good DAC performance; as long as converter designers provide adequate jitter attenuation. A test signal has been devised to allow consistent assessment of data jitter susceptibility of clock recovery systems. Measurements made with this signal has shown the susceptibility of some DACs to converting data jitter to sampling jitter, but this is not universally the case. The response of one of the DACs demonstrated that it is possible to make clock recovery systems that do not have this behaviour. Therefore sampling jitter resulting from data jitter is simply the result of poor equipment
design and not, as has been suggested (among others by [4]), a fundamental shortcoming of the interface specification."
The tools that were developed to make the measurements have 143 dB dynamic range.
"DAC A and DAC B both show sensitivity to data jitter. DAC A shows no attenuation below 20kHz as the level of the sidebands are commensurate with those of the applied square wave up to that point. DAC B shows the effect of the 2.38kHz PLL corner frequency as the higher harmonics in the jitter signal are attenuated. DAC E, which is operating in E1 or 1.2kHz bandwidth mode, shows the sidebands at about -106dB."
DAC A, which had "no attenuation" of jitter showed sidebands at -79.4 dB or less.
If you are getting pops, clicks, or dropouts due to data loss, it may be due to bad cables or loose/corroded connections, but believing bad cables can cause distortion or change tonal balance is s silly as believing that Toslink causes lack of "air" in digital transfers because it uses low frequency infrared LEDs.. AES specs allow 40ns jitter on the digital signals, but only 4ns jitter in the D/A, so any equipment SHOULD have > than 10:1 jitter rejection. If it doesn't, $1000 cables aren't the solution.
See also the discussion beginning at p56 in http://www.tcelectronic.com/media/163459/tc_electronic_system_6000_mkii_operation_manual_english.pdf
Julian Dunn* and Ian Dennis, Prism Sound Limited Presented at AES 96th Convention, February 1994
© Julian Dunn 1994
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.68.2092&rep=rep1&type=pdf
"CONCLUSION
Several tools have been developed to measure the digital audio interface parameters discussed in [2], including a jitter modulator to produce known and controllable amounts of jitter so that measurements of jitter transfer function and jitter tolerance can be made. Mathematical models to relate sampling jitter levels and resultant distortion products have been refined and measurements have been made using a wide dynamic range spectrum analysis tool. Results indicate a good correspondence. The jitter attenuation recorded by results from some of the converters indicate that, as well as being impractical, it is not necessary to specify maximum interface jitter levels commensurate with sampling jitter levels necessary to ensure good DAC performance; as long as converter designers provide adequate jitter attenuation. A test signal has been devised to allow consistent assessment of data jitter susceptibility of clock recovery systems. Measurements made with this signal has shown the susceptibility of some DACs to converting data jitter to sampling jitter, but this is not universally the case. The response of one of the DACs demonstrated that it is possible to make clock recovery systems that do not have this behaviour. Therefore sampling jitter resulting from data jitter is simply the result of poor equipment
design and not, as has been suggested (among others by [4]), a fundamental shortcoming of the interface specification."
The tools that were developed to make the measurements have 143 dB dynamic range.
"DAC A and DAC B both show sensitivity to data jitter. DAC A shows no attenuation below 20kHz as the level of the sidebands are commensurate with those of the applied square wave up to that point. DAC B shows the effect of the 2.38kHz PLL corner frequency as the higher harmonics in the jitter signal are attenuated. DAC E, which is operating in E1 or 1.2kHz bandwidth mode, shows the sidebands at about -106dB."
DAC A, which had "no attenuation" of jitter showed sidebands at -79.4 dB or less.
If you are getting pops, clicks, or dropouts due to data loss, it may be due to bad cables or loose/corroded connections, but believing bad cables can cause distortion or change tonal balance is s silly as believing that Toslink causes lack of "air" in digital transfers because it uses low frequency infrared LEDs.. AES specs allow 40ns jitter on the digital signals, but only 4ns jitter in the D/A, so any equipment SHOULD have > than 10:1 jitter rejection. If it doesn't, $1000 cables aren't the solution.
See also the discussion beginning at p56 in http://www.tcelectronic.com/media/163459/tc_electronic_system_6000_mkii_operation_manual_english.pdf
And I guess you are right. But people tell us that education cures ignorance. I have always had an issue with that (-:.
For the record, if you try to educate a non optimum iq person into a vessel of knowledge you get Joceyln Elders and that is quite scary,
I think Stuart at one point somewhere found the expression 'Chronic Underachievement Disorder' but I guess he has been too chicken to use it 😀
Jan
Don't get me started!
Let's just say I am alive right now despite the best efforts of a number of GPs rather than because of them as it should be.
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