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Old 13th February 2012, 07:02 PM   #2311
SY is offline SY  United States
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I'm not a psychic.

Quote:
I would call that pretty conclusive and convincing, wouldn't you?
No, not really.
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Old 13th February 2012, 07:04 PM   #2312
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Originally Posted by SY View Post
I'm not a psychic.
I always get psychic and psychotic mixed up! Makes dating more interesting!
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Old 13th February 2012, 07:11 PM   #2313
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Originally Posted by simon7000 View Post
I always get psychic and psychotic mixed up! Makes dating more interesting!
You've met my first wife, then?
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Old 13th February 2012, 07:19 PM   #2314
bcarso is offline bcarso  United States
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I chuckle at my friend Marshall's company name, Psychotechnology, as it can be easily interpreted as technology for psychos.

On the runs of speaker cable, I recall a piece in the long-defunct Audio magazine by Richard Greiner, definitely in the cable-skepticism camp, who attempted to measure with undisclosed but (we were assured) very special instrumentation that there were no differences among cables. However, even though his presumably foregone conclusion was amply demonstrated to his satisfaction, even he suggested that one would do better locating amplifiers adjacent to speakers and running line-level signals to them, rather than having the speaker signals travel over long cable runs.

However with some of the stranger unshielded, poorly shielded, or odd-grounding-convention interconnects that Fremer describes using with the big MBL amp mentioned a ways back, I fear all bets are off.
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Old 13th February 2012, 07:23 PM   #2315
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Originally Posted by bcarso View Post
Apropos of the underpinnings of a lot of this stuff: an excellent qualitative review of EM, in the context of Tesla's confusions about "non-Hertzian" waves, thanks to friend Erik Margan:

The REAL Science of non-Hertzian waves, by Paul Nicholson
I get stuff sometimes from Erik too, the LHC electronics are amazing. I never saw this critique of Tesla, very good but this is becoming another cable thread as well as how many -140dB things add up to the audibility threshold of one standard US housewife (perferably doing the dishes in another room).
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Old 13th February 2012, 07:29 PM   #2316
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Greiner's recommendation about short cables was based on frequency response- he did a paper showing that higher resistance cables could cause audible spectral balance shifts, so recommended that cables be kept short and that low DCR is desirable. That's why I use Home Depot outdoor extension cords (meant for high current devices like lawnmowers and compressors) for my amp-to-speaker wiring.
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Old 13th February 2012, 07:55 PM   #2317
DF96 is offline DF96  England
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Originally Posted by dvv
I would call that pretty conclusive and convincing, wouldn't you?
Convincing about what? What difference did you hear? What steps did you take to ensure that the person doing the listening could not be influenced in any way by the one doing the switching? What function did the cables have in the unit? Insulation? Source impedance? Integrity of soldering? Precise positioning? Were the cables identical in every respect apart from the metal used? A bit of stray capacitance change at a high impedance node can easily change the frequency response by a little bit. Making an audible difference is easy; correctly ascribing it can be harder.
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Old 13th February 2012, 08:38 PM   #2318
bcarso is offline bcarso  United States
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Originally Posted by scott wurcer View Post
I get stuff sometimes from Erik too, the LHC electronics are amazing. I never saw this critique of Tesla, very good but this is becoming another cable thread as well as how many -140dB things add up to the audibility threshold of one standard US housewife (perferably doing the dishes in another room).
I just wanted to provide something of a reality check for those who tend to think in terms of circuit theory as opposed to the bigger EM "picture". It has bearing on cables, but of course much else.

I got into the Tesla e-mail exchanges late in the game, by which time distribution included Barrie Gilbert, John Addis, Kendall Castor-Perry, Dennis Feucht, Dan Sheingold, and, based on all the unfamiliar names, probably a host of Erik's colleagues at university and CERN.

Brad Wood
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Old 13th February 2012, 09:54 PM   #2319
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"You may have to remove all the other compensation and still have a minimal miller compensation. See how it works out."

Down to 27p in the miller. It claims to be stable with 3. I don't think the model is useful past that as removing all three of the others have no effect. I suspect on the bench far more will be revealed. I need to lay in a supply of high quality small caps to check reality.

I am having lots of trouble getting Simetrics to run the P-Z tests. I am copying the demo but it keeps telling me the in or out is shorted. I am wondering if it can do more than one stage. It is an unsupported function.

Increasing the cap in the feedback line seems to limit the BW without causing distortion to the test pulse. What is the thinking on an f3 value to roll off? 25K? 50K? Target about half a dB at 20k?

Question on standards. At one time, it used to be assumed 2V RMS was the standard for full power. The 120 is 1.1, 220 is 1.4,1.5 common. Is there a reason to set the CLG to one number or another? Gain between amps seem to vary from less that 20 to over 30.

Dismissive of power cables? Yes. Totally. I know what they are plunged into. Several mechanical connections, lots of not high purity solid core wire, breakers, etc. There is a point where a laboratory theory that is valid and measurable but is less than one in the hundreds of millions just is not relevant.
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Old 13th February 2012, 10:03 PM   #2320
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Originally Posted by ThorstenL View Post
I do not per se disagree, however that is not how the market works right.

If you wish to pillory BS merchants make sure your targets are worth the efforts.

You can start with Hedge Funds and Investment bankers.

Then proceed with the whole Soft-Drinks, Washing Powder, Tooth-Paste and Toilet Paper industry.

All these early ones are much more worthwhile targets than cable makers, moreover there is a lot more money in it.

I personally prefer to use the "live & let live" approach.
Big crimes are taking place, let the little ones go.

When you stop spouting stuff like this, TL, I'll take the time to check your arithmetic.

You obviously recognise that there is a considerable amount of BS being touted in audio. but instead of lending your talents to eradicating it, you do exactly the opposite, both for your personal profit and to gratify your ego. It's not an edifying sight, nor one calculated to make friends, only customers and acolytes.

Quel dommage.

Quote:
Originally Posted by ThorstenL View Post
BTW, as I repeatedly have intimated there are indeed a number of ways that can reduce the issues appreciably AND retain electrical code compliance, but they are neither straightforward nor easy, nor particularly widely known, though most will become extremely obvious if one actually removes the mental blinders and the "rule of the dumb" and actually considers reality and thinks it through.
So let's see your suggestions so we can judge for ourselves.

While we're at it, 'mental blinders' and "rule of the dumb" are well over the line as regards disrespect of members, IMO, so please, desist from these little asides.

Ciao cc
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