I think we were putting DC bias (electric attraction) between the two wires of the fig 8 cable.
The signal caused a 2nd harmonic modulation.
I know the ingredients of the experimental jig still exist.
Given a week or two we can revisit what we think we found....mechanical modulation of the pair, causing 2nd harmonic production...or something like that.
Dan.
Hornman,
It's no secret how to get a coil speaker system with a fairly flat impedance curve, especially if your intent is to kill the dynamics and choke out all the life in the music with the intent of just impedance flattening.
Just one of the many reasons it's not pursued past whats necessary ...
I find back EMF servo controlled woofers to sound unnatural Demian, i have not heard the Entec or all servo woofers , but enuff ( velodyne,genesis )to tell electronics at work. I haven't heard any recently, any changes there ...?
Wasn't there a DIY cable offered here powered by dc, i think maybe for shielding and not in the manner you are describing ....
Hi George
A Monty python fan eh, cool. Somewhere I have an old 3 sides LP of theirs called something like “matching tie and handkerchief”. It was a real surprise when I put the needle down on maybe the 10th playing and then heard a completely new track as it played the second groove on that side.
A simple amplifier oscillates or become regenerative (an old radio term) when the signal that is returned for negative feed back, exceeds a 120 degrees phase shift relative to the normal case.
Once 120 degrees is reached, the formerly subtractive signal becomes additive, maximally so at 180 degrees which is where the amplifier will end up osculating and where the now positive feedback is greatest. The Bode criteria calls for the amplifiers open loop gain having reached 0dB below the frequency the phase has become additive.
For those who wish to do distortion measurements where more than one element is involved, the trusty (and now cheap) HP-3562a can do 2ch vector subtraction distortion measurements.
For example when done normally, the mag and phase of an amplifiers distortion will add or subtract from what the loudspeaker does.
With the 2ch vector approach, the drive signal and output are compared, the difference is read.
Best,
Tom Danley
Danley Sound Labs
Six Grooves On Each Side...
Commentator; Ken Howard
331/3 R.P.M.
Side 1:-
"The Post-War Stakes"
The Australian Race Game
Six Different Winners
Starters Numbered As Follows
(1) Carioca
(2) Delta
(3) Bernborough
(4) Shannon
(5) Dalray
(6) Hydrogen
side 2:-
"The Pre-War Stakes"
The Australian Race Game
Six Different Winners
Starters Numbered As Follows
(1) Phar Lap
(2) Hallmark
(3) Nightmarch
(4) Peter Pan
(5) Carbine
(6) Windbag
Aussie betting game history...Aussies have been known to bet on two flies walking up a pub wall.
Dan.
Commentator; Ken Howard
331/3 R.P.M.
Side 1:-
"The Post-War Stakes"
The Australian Race Game
Six Different Winners
Starters Numbered As Follows
(1) Carioca
(2) Delta
(3) Bernborough
(4) Shannon
(5) Dalray
(6) Hydrogen
side 2:-
"The Pre-War Stakes"
The Australian Race Game
Six Different Winners
Starters Numbered As Follows
(1) Phar Lap
(2) Hallmark
(3) Nightmarch
(4) Peter Pan
(5) Carbine
(6) Windbag
Aussie betting game history...Aussies have been known to bet on two flies walking up a pub wall.
Dan.
a.wayne
I see no mechanism to change the basic character of the speaker just because you have a faraday ring? Yes it will lower the efficiency some if it is doing its job but that would not change the basic moving structure. I see more of an issue when the flux rings are just at the ends of the travel and suddenly the energy in the gap changes, that would be a real distortion producer in my eyes.
I see no mechanism to change the basic character of the speaker just because you have a faraday ring? Yes it will lower the efficiency some if it is doing its job but that would not change the basic moving structure. I see more of an issue when the flux rings are just at the ends of the travel and suddenly the energy in the gap changes, that would be a real distortion producer in my eyes.
No.gpapag said:
That topic has been laid to rest by the Mods so lets' not try to revive it!
Mainly 1, with some 2. Rarely 3 unless cables are very long.
Nothing different happens at 120 degrees. 90 degrees, maybe - if there is enough loop gain. The issue is whether the locus of loop gain encloses the (1,0) point. If yes, it oscillates. If no, it doesn't. I think that is what Bode said? (Or was it Nyquist?)Tom Danley said:
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George,
2 Volts--spec'd
22K Oms last I looked
Less than 20 db from clipping is about the maximum level for quality reproduction. I use 30 for live orchestras.
So roughly 9 microamps current in the interconnect.
Now if a coulomb per second is one ampere and the velocity of propagation in a cable is 80% of C, how many charges (For simplicity assume DC) are propagating in a one meter cable?
2 Volts--spec'd
22K Oms last I looked
Less than 20 db from clipping is about the maximum level for quality reproduction. I use 30 for live orchestras.
So roughly 9 microamps current in the interconnect.
Now if a coulomb per second is one ampere and the velocity of propagation in a cable is 80% of C, how many charges (For simplicity assume DC) are propagating in a one meter cable?
Ah, but he didn't ask what carries the signal.
And, he didn't ask how fast they're going.
He asked how many charges are propagating.
I'm on to your trick questions Ed..you had to get up earlier today...😀😀
jn
"Dear friends, in these days of modern times, when you can't tell the ACs from the DCs, well, aren't we all yearning for someone to turn on some stopping power?"
Agreed. But his question was how many electrons are motivatin along.
His hints will tell you how many electrons per second will pass by a cross section of the wire, we need the wire cross section to determine the current density therefore the overall electron velocity, and the mention of prop speed was a diversion.
Every electron in the conductor which is mobile will move as a result of the voltage gradient in the wire. So the question really is how many electrons are available to move in a 1 meter length of metal. What he forgot to add was, what is the guage of the core wire, and what is the effective guage of the shield return, as we need the total volume of metal to answer the question.
If the question was meant to be how many electrons in the entire cable including shield, then the average answer is zero at any cross section. Otherwise there would be either an additional current path, or there is a charge buildup.
jn
Almost there. Current density and charge interaction is the issue. Electron drift ain't it.
Now does anyone want to discuss how Ohm came up with his equation?
I feared we might be heading off to Essex to study 'fuzzy distortion', due to a misunderstanding about the necessary conditions for shot noise to appear.
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