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In Reply to: RE: Marginally unstable amps posted by geoffkait on January 11, 2013 at 05:29:16
No, i wasn't, but paralleling the driven line with another one at ground potential does shield the hot lead a bit more.
The first time i heard of the frame ground lead was from an old time audio acquaintance, Roger Grodinsky. My boss and i were invited to his house and among the things he demonstrated was grounding the speaker frame as descried.
He insisted it made a big difference, my boss (a physicist) said he wasn't sure and asked if he could try an experiment. We sat and listened as he connected and disconnected the ground and we couldn't hear a difference.
My boss and he switched places and my boss opened and closed the circuit out of sight behind the speaker and Roger couldn't tell either which was puzzling so we went on with other things..
The reason it doesn't effect the loudspeaker driver end at all is that the voice coil that is connected to the amplifier, is insulated by many megohms of air gap from the metal frame which receives no electrical power.
Do you know what a ground loop is.
Did you know that the current in a speaker line is always fully balanced, equal but opposite currents?
Follow Ups:
I'd say all that is pretty anecdotal. What's it all mean, Jelly Bean, maybe that physicists can't hear, who knows."Reasons why audiophiles don't hear tweaks are (1) their hearing is impaired, (2) they didn't follow instructions, (3) there's something very wrong with their system AND/OR (4) their system is not resolving enough." - George Tice
Edits: 01/25/13
It is anecdotal and the physicist was not an audiophile. I was a transducer designer at the time so seeing no conceivable way it could effect the transducer i was curious but skeptical as well. Roger made a well regarded dynamic range expander back then which i used back then so i was very open to hearing what he described.
With none of us being able to tell when the connection was made or broken, that was a disturbing surprise to Roger who had been sure it made a big difference and wanted to demonstrate it to us.
Too often we change something and listen and decide it sounds better and to us it really does sound better.
The problem is what we hear as the conscious image appearing in sound in front of us, is very much made up of what we have learned and know and what we think or expect.
An obvious example that demonstrates that is that when you have poor intelligibility, one can understand a sentence or paragraph, much better than the same number of random words. A less obvious example is how we can tell what direction the source of sound is in height, left /right and front to back from only two sampling points in space.
When building loudspeakers the problem is very strong, you pour your heart and sole into something, spend endless hours festering on minutia and so the old adage is very often true "the best sounding speakers are the ones you just built".
In the real world, It's an assertion which in spite of how strong you believe it, can only be honestly validated by listening to it side by side with past work switching back and forth.
That latter step, comparing with and without or A vs B without knowing which, is a step that many in audio promotion want to avoid at all costs being a heretical suggestion or something.
If you hear a difference while switching and not knowing which is which, the difference is large enough to be detectable under those conditions, removing your internal bias.
The problem for me has been not if a change makes a difference but is it better than before because with various coloration's (nothing is perfect), you can find some recordings which sound worse and some that sound better than the prior version.
When it's not clear, i find it's best to go with what the TEF machine says is closer to the ideal, in fact, with the Synergy horns, how they work / measure drove the entire process.
I am pleased how they work, it doesn't matter how many drivers they have, you can walk up to one, stick your head in the horn mouth and never hear any other source of sound than one source floating somewhere in front of you. No awareness there is a multi way system or may have many drivers, no crossover phase shift or lobes and nulls in the polar pattern, they really do act like / measure like / sound like a single but impossible full range driver with constant directivity.
That result was something Dick Heyser wrote about as an ideal in a paper shortly before his death 25+ years ago, the Synergy horn developed using his measurement process TDS to realize it. I wish i could show it to him.
Well, if you're saying that audiophiles are subject to expectation bias, self fulfilling prophecies, high hopes, placebo effect, Backfire Effect and all manner of bizarre psychological effects then I couldn't agree more.
Agreed, no one is immune to what they already believe.
"Reasons why audiophiles don't hear tweaks are (1) their hearing is impaired, (2) they didn't follow instructions, (3) there's something very wrong with their system AND/OR (4) their system is not resolving enough." - George Tice
Are those the only possibilities?
Queue the rolled on the floor laughed my ass off emoticons.
It's only easy if your deaf.
Dunno. Whaddaya got?
No.
Some tweaks work because they fix a problem with a system. They may not work in another system that doesn't have that particular problem.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Name one. Betcha can't.
Speaking of can't, lets hear your explanation of "how this works", what effect the ground wire has on the driver?.
You use engineering buzz words but what can you design with them?
Have no idea how it works. How's that for engineering buzz words?
Any tweak to a digital transport (or computer) can improve sound if it reduces jitter or noise. However, the effect of the tweak is dependent on poor jitter and noise rejection in the DAC that's downstream. If the DAC is replaced with a better DAC with excellent rejection or a good reclocker is placed between the transport and the DAC, then tweaking the transport will have much less impact on sound quality, possibly none.
Another example are tweaks associated with removing noise from AC power lines or radiated EMI. These affect sensitive analog components, but don't affect better designed components that have more noise immunity. These problems and possible cures will be familiar to those audiophiles who are also ham radio operators.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Ah, Hope springs eternal in the heart of the confirmed tweakaphobe.
The old warhorse, "good solid engineering" argument. The better designed components? As opposed to the components that are not well designed? That's funny!
I gave specific examples, as you requested. Now imagine the exact same situation, except that the people don't know anything about engineering or physics. Results will be the same. Tweaks will work in some systems, but not in others. Since scientific knowledge is increasing and since new technologies have unforeseen quirks, this situation can also happen even when the people are up to date in their knowledge.
One of the attributes of quality components is consistent operation in a large range of environments. In that sense a BMW is a better car than a Ferrari, as it (supposedly) spends less time in the shop. It may not be as fun to drive or attract as many hot women, but those are different questions. :-)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
You do realize that digital components are not so much susceptible to EMI/RFI as they are generators of it? Hel-loo! There is no escape.
Yes, I've heard the car analogy before, but I don't buy it. There are tons of BMWs in the shop here, they actually appear to be a maintenance nightmare, not much better than, say, Jaguar. So there goes that particular argument. I'll take a Ferrari ANY day. The maintenance argument ironically is supposed to make Ferrari owners feel bad and folks who drive Toyotas feel good. Exactly the same illogical argument you're using for tweaks!
You did notice that I wrote "(supposedly)", didn't you? Alas, I am too well aware of the specifics with regard to BMW's. :-(
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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