mach1 said:
I'm willing to bet a pint the crystal in the first CD player was in the middle of the circuit board, or at least far from the board's mounting points, whereas the crystal in the second player is either closer to a screw, or it's well damped.
Well, that means the LP12 is *revealing* and the Technics is *soulless*. Didn't you get the memo?
Sometimes it seems that audiophiles are the same kind of guys who chase high maintenance women: they start wondering where the magic has gone if there isn't a hysterical episode every once in a while. Meanwhile the rest of us enjoy our lives.
Nope - I have always found a mahogany / Cambodian teak laminate with equidistant golden section zircon inserts a more effective counter to the excessive warmth of Maple than roller bearings...
This arrangement stops the buildup of standing waves in the support which can cause a significant impairment of CD crystal function at the quantum level.
pm
BudP said:
Sorry, Bud.
I thought it would be nice for this thread to stay out of the gray areas, where vagaries and slight subtleties reign. One can find lots of that in the "beyond the ariel" thread.
I, for one, don't want to get mired in the suggested differences between the way two pieces of wire sound with the only difference between the two, is the colour of the insulation used.
I thought it would be a good place to highlight some or the more interesting things that are out there in the wide world of audio. You know, poke a little fun, then an "audiophool" comes rushing in all indignant and sets everyone straight.
Light musings.
shielding loudspeaker cables
EC8010,
EMI is a notoriously difficult problem to manage because the underlying physics is complicated. Where I work we have a whole team of experts who develop simulation models and modeling methodologies in an attempt to make the problem computationally tractable.
The modeling difficulty lies in the need to solve Maxwell's equations that govern E+M wave propagation. These equations have analytic solutions only the simnplest of geometries. For everything else, numerical methods must be employed. And remember, at this point we have not yet even begun to consider the effects on active circuitry.
From a practical point of view, EMI is best controlled by putting the sensitive electronics in a sealed, conducting enclosure and making sure no EMI gets in or out over any cabling or through any other apertures.
If the amplifier has a load isolation inductor (many amps do in order to isolare reactive loads), that will offer some protection. The other aproach is to wrap the speaker cable several times through a ferrite core. Doing so creates a so called transmission line transformer. It will block common mode RF energy, but will have no impact on the (differential) audio signal. The same approach can be used for any cabling going to/from the amp.
BTW, I am currently designing an amplifier, and I have included line filter modules on the AC mains and plan to use ferrites on the input. The amp also has load isolation inductors.
I'll try simulating my amp's performance in the presence of RFI.
JCM
EC8010,
EMI is a notoriously difficult problem to manage because the underlying physics is complicated. Where I work we have a whole team of experts who develop simulation models and modeling methodologies in an attempt to make the problem computationally tractable.
The modeling difficulty lies in the need to solve Maxwell's equations that govern E+M wave propagation. These equations have analytic solutions only the simnplest of geometries. For everything else, numerical methods must be employed. And remember, at this point we have not yet even begun to consider the effects on active circuitry.
From a practical point of view, EMI is best controlled by putting the sensitive electronics in a sealed, conducting enclosure and making sure no EMI gets in or out over any cabling or through any other apertures.
If the amplifier has a load isolation inductor (many amps do in order to isolare reactive loads), that will offer some protection. The other aproach is to wrap the speaker cable several times through a ferrite core. Doing so creates a so called transmission line transformer. It will block common mode RF energy, but will have no impact on the (differential) audio signal. The same approach can be used for any cabling going to/from the amp.
BTW, I am currently designing an amplifier, and I have included line filter modules on the AC mains and plan to use ferrites on the input. The amp also has load isolation inductors.
I'll try simulating my amp's performance in the presence of RFI.
JCM
Hello analog_guy, I must confess that I have not actually tried screened loudspeaker cable, but I can see a logical reason as to why it might help. Yes, most transistor amplifiers have an output inductor, but this is often in parallel with a 10 Ohm resistor. A N Thiele (of Thiele and Small fame) addressed this problem explicitly and suggested filters at the output of amplifiers to prevent backwards injection of EMI. The problem (as I'm sure you're aware) is that as one has no control of the EMI environment, any "fixes" tend to take on a snake oil quality and predictability is low. And then, of course, there's the possibility that SY mooted, that the amplifier is conditionally unstable...
EC8010 said:
I suspect SY is right on this one. A fellow over on Usenet (Dick Pierce) points out that some "audiophile" DACs have indifferently stable S/PDIF receivers, and mirabile dictu, they happen to be the most "revealing" of different cable types. Could it be the receiver jitter depends on how the cable transmits pulse risetime/falltime? Nooooo, this stuff is all unconditionally stable! Honest!
Speaking of amplifiers, class-D amps have a great big capacitor to ground right on the output before the signal goes anyplace else. I'd bet a UcD will be less "revealing" of speaker cable differences than, say, a Naim (the older ones didn't play well at all with high capacitance speaker cables).
Francois.
Going on the assumption that that your audiophile amp is lacking in the stability department and is sensitive to EM and RF interferance, how can these deficiencies be corrected by using +$10K speaker cables? Cable construction is not magic, it's meant to carry current from point A to point B without degradation. A single unshielded conductor, of adequate size will do that. Add shielding if your amp is poorly designed, wrap tin-foil around your speaker cabinet while your at it to shied the componets inside. The only other changes that can be made to get different results are negitive.
I've read about "skin effect" and "oxygen free copper" and "polarized crystalline structures" and " teflon insulation" and " low capacitance/low inductance" and "triple shielding" and on and on. All marketing, nothing else.
The bottom line is, if you believe it makes a difference, do it. Better start saving though...
I've read about "skin effect" and "oxygen free copper" and "polarized crystalline structures" and " teflon insulation" and " low capacitance/low inductance" and "triple shielding" and on and on. All marketing, nothing else.
The bottom line is, if you believe it makes a difference, do it. Better start saving though...
It's true that the cables used in home audio set-ups generally are too short to make shielding a factor. (They are generally too short to even matter.) Lots of ultra high-end decks and tonearms have the tonearm leads exposed without any problem. But it's equally true that our environments are getting increasingly noisier, with cell phones, wireless LANs, etc. Of course, we still deal with, does it matter? But considering one meter shielded microphone or instrument cable costs about a $, I do not consider myself cheated.
"Skin effect" (i.e. self-inductance), solid-core, OFC (first used in pro audio), etc. are snake oil in that they have no scientific foundation whatsoever. While self-inductance is real, the level of self-inductance in a cable is too low to matter. Unshielded interconnects also fall into the category of snake oil. What makes unshielded interconnects snake oil is the claim that (I'm not making this up) unshielded interconnects have more open sound than shielded interconnects. The same applies to solid-core and OFC. Solid-core is used in mains installation cable. OFC is used in microphone cable and transformers. Solid-core is stiff. OFC is soft. But once you attribute other qualities to them, you have created snake oil.
It would be presumptuous of me to say a cable or anti-vibration device cannot possibly make a difference. But if they did in my system, I would assume the problem is the electronics. I would assume that the amp or whatever is defect and needs to be repaired. I wouldn't go out and buy a new cable, high-price or otherwise. Turntables are a bit different when it comes to vibrations. But I would assume that the manufacturer has taken sufficient steps to make it as vibration proof as reasonably possible if it's a deck of any quality to speak of.
"Skin effect" (i.e. self-inductance), solid-core, OFC (first used in pro audio), etc. are snake oil in that they have no scientific foundation whatsoever. While self-inductance is real, the level of self-inductance in a cable is too low to matter. Unshielded interconnects also fall into the category of snake oil. What makes unshielded interconnects snake oil is the claim that (I'm not making this up) unshielded interconnects have more open sound than shielded interconnects. The same applies to solid-core and OFC. Solid-core is used in mains installation cable. OFC is used in microphone cable and transformers. Solid-core is stiff. OFC is soft. But once you attribute other qualities to them, you have created snake oil.
It would be presumptuous of me to say a cable or anti-vibration device cannot possibly make a difference. But if they did in my system, I would assume the problem is the electronics. I would assume that the amp or whatever is defect and needs to be repaired. I wouldn't go out and buy a new cable, high-price or otherwise. Turntables are a bit different when it comes to vibrations. But I would assume that the manufacturer has taken sufficient steps to make it as vibration proof as reasonably possible if it's a deck of any quality to speak of.
There's certainly some flights of fancy out there, that's for sure. But don't let that blind you to the possibilities that some stuff is real, and when it is, finding out the cause is pretty interesting.
May I give an example? When switching between two cables connecting phono (high output MM) to preamp, a definite difference was heard, one cable having a raspy sound on certain notes and a more hashy presentation compared to the other. One cable was a high end silver and Teflon coaxial construction using top-of-the-line RCA plugs, the other was a generic tinned copper polyolefin coax with decent-but-nothing-special RCA plugs.
Easy to pick blind 100% of the time. Now what was the cause?
May I give an example? When switching between two cables connecting phono (high output MM) to preamp, a definite difference was heard, one cable having a raspy sound on certain notes and a more hashy presentation compared to the other. One cable was a high end silver and Teflon coaxial construction using top-of-the-line RCA plugs, the other was a generic tinned copper polyolefin coax with decent-but-nothing-special RCA plugs.
Easy to pick blind 100% of the time. Now what was the cause?
SY said:
Off the top of my head, possible causes might be triboelectric effects, connector corrosion, perhaps even a dodgy solder connection. Hard to tell without looking at the wire.
I think high impedance links must be eschewed and interconnects should be run at no more than a few kOhms, because a lot of cable effects seem to go away once you have more than a few microamps of current in the wire. I also recommend going balanced for common-mode noise immunity - anything external which gets into the wire most likely will hit both conductors and get canceled out at the receiving end. There's a reason pro audio setups run low impedance balanced, and it's not because XLR connectors are dead sexy.
DSP_Geek said:
It's because our 'interconnects' are often 200+ feet long. Hard to argue the need for home use though, especially phono cartidges which usually tied output grounds pins to the body and were no longer balanced. No arguing the technique in general however, especially transformer coupled or using true instrumentation amps (the latter rare in pro audio.) I set up a 2 km run using a line amp at the source driving a 600:150 connected transformer to a 150:600 connected transformer at the far end. 1 dB down at 18 kHz, S/N in the -65 dB range, low distortion and well suited to the FM application required.
My guess: poorly designed "top-of-the-line RCA plugs" causing rectification?
Sy, more information please - how do you know that was the cause ? Did you measure the charge / potential on the interconnect and that on the socket ?
Are you implying that the charge was built up from the friction induced by inserting and removing the plugs, or from friction between the interconnect outer sheath and the external environment? ? If the former, was the plug surface plating material different on the two cables? Was the plating material on the plugs different to that on the sockets?Was there an oxide layer on either of the sets of plugs or the sockets?
In my experience, copper and silver sound quite different as conductors, and perhaps this physical difference could offer just as plausible an explanation.
phn, you state:
Many years ago, I remember reading an article in HFNRR on signal propagation in cables authored by Malcolm Hawkesford (i think - can't be sure). In it the author offered a mathematical proof that high frequency signal propagation (at frequencies that could negatively impact music reproduction) is indeed impacted by skin effect at the diameters commonly used in signal cables. The inference was that small diameters (in the order of 0.25mm dia) offer plausibly superior hf characteristics to those in the order of 1 - 1.25mm dia. I believe this to be reason why some manufacturers (eg Cardas and Kimber) use a mix of large and small dia wires in their small signal cables
Antother interesting point I remember, is that the electromagnetic wave induced by a signal actually propagates around the outside of the conductor, thereby travelling through the insulating material. This could possibly go some way towards offering an explanation for some of the observations on cable sound posted here by BudP (but which appear to have mysteriously disappeared ?). If they have been pulled by the author or moderators I feel rather saddened.
I am now going outside and may be some time ......
pm
IMO, DSP_Geek has a very valid point. Though I can't hear the difference between decent capacitors, I can easily hear the difference between different low level interconnects. The reason can always be determined if you make enough measurements of well understood phenomena, even if the cause is a bit exotic, but it shouldn't happen at all. We seem to be stuck with the high impedance levels from the days when tube preamps couldn't drive much and power amp inputs were chosen accordingly. Plus, every manufacturer does it differently. Just like scope inputs are standardized to specific R and C values, it would make more sense today to standardize on some lower impedance- all power amps would present a purely resistive 600 ohm load, and all preamps would be capable of driving that load. Lower the impedance and issues of cable capacitance, DA and DF would disappear or be greatly reduced. Of course finding decent coupling caps would then be near impossible, but coupling caps are no longer a necessity with decent circuitry. Or, why not go to a current drive scheme and keep voltage near zero. Solves a bunch of problems, though I'm sure more would show up to replace them.
I think I'm hearing a difference between conductors, but the psychological difference between brass and silver is too hard to overcome! Lot's more tests needed to make up my mind on that somewhat controversial topic.
I think I'm hearing a difference between conductors, but the psychological difference between brass and silver is too hard to overcome! Lot's more tests needed to make up my mind on that somewhat controversial topic.
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