I once witnessed a compelling demonstration for one of those oil products. Airplane, drained oil, flew the pattern replaced oil. Still think it was a tricked out pan.
You're entitled to think what you like.
Digital pump makes for easy, accurate dosing with fuel additive GO2
Digital pump makes for easy, accurate dosing with fuel additive GO2
And as usual, Rod is halfway there.
He also misunderstands IC's and PC's and their interaction with audio systems.
Yet so many cling to his errors.
jn
Quarter wave transformers are excellent when one has a very narrow band of frequencies needing impedance conversion.
While the chart is great, is only hints at the considerations for wavelengths far longer than the 1/4 wave.
jn
...if they are that stupid, how did they get all that money?
Because we all give them OUR money! Witness the geeky loser guy attending Harvard. He tries getting pictures of girls via his "system"............people being what they are, gives him any and all information, photos & all.
Since it seems, no one values their own privacy, individuals "sign off" on this info ......collecting, organizing, categorizing, prioritizing multiple sources..........a Gold mine, a marketers dream, all given up freely.
Then we have the guy with the gift of gab, arm twisting, con man........gets a programmer to do the "dirty work", the actual creative one. He buys the program, turns around & actually convinces IBM to use it......yes some forward thinking but more likely, a well spoken gab job, Used car style.
Use critical thinking when shelling out anything of value that you have.
Mark Zuckerbergs reaction upon seeing the sheer bulk of personal information that his brand new site was accumulating. "F****** idiots".
_______________________________________________Rick..........
Because we all give them OUR money! Witness the geeky loser guy attending Harvard. He tries getting pictures of girls via his "system"............people being what they are, gives him any and all information, photos & all.
Since it seems, no one values their own privacy, individuals "sign off" on this info ......collecting, organizing, categorizing, prioritizing multiple sources..........a Gold mine, a marketers dream, all given up freely.
Then we have the guy with the gift of gab, arm twisting, con man........gets a programmer to do the "dirty work", the actual creative one. He buys the program, turns around & actually convinces IBM to use it......yes some forward thinking but more likely, a well spoken gab job, Used car style.
Use critical thinking when shelling out anything of value that you have.
Mark Zuckerbergs reaction upon seeing the sheer bulk of personal information that his brand new site was accumulating. "F****** idiots".
_______________________________________________Rick..........
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I see it differently
This nomogram shows easily what load may the line present to the amp output depending on it’s charact. impedance and considering far end load impedance varying, i.e. no proper zobel across the load.
e.g. Load resistance:100 Ohm (speaker coil at high freq., easily)
With 12.5 Ohm line, Input resistance=1.2 Ohm
With 24 Ohm line, Input resistance=7.5 Ohm
With 50 Ohm line, Input resistance=22 Ohm
With 100 Ohm line, Input resistance=100 Ohm
In a nutshell. Lines with low charact. impedance are risky when not properly zobeled.
Yes, these all for some frequencies well above the audio spectrum. But do we know the RF that is picked up by the cables or the MHz signal from some internal to the amplifier oscillation?
George
The nomogram is based on the equations for a quarter wave transformer. As such, it is only applicable at or very near the frequency which represents a quarter wavelength of the transformer length.
It is based on the reflection coefficients at both ends of the intermediate t-line.
jn
Since I have only been working with RF and general electronics for now close to 40 years, and clearly have no clue about what I'm doing, would some of you care to show some calculations for a quarter wave transformer for a typical amp/loudspeaker combo, at least as a general example?
Nobody can. That's been my point, it is specific only for a narrow band of frequencies centered around the 1/4 wavelength.
jn
I know - over the years I've made a fair number of them for VHF/UHF........
Quite frankly, I thought my command of the english language was sufficient to detect sarcasm and such foolery....😉
maybe not so - I'm beginng to think that some here are dead serious with this loudspeaker transmission line stuff.....
Quite frankly, I thought my command of the english language was sufficient to detect sarcasm and such foolery....😉
maybe not so - I'm beginng to think that some here are dead serious with this loudspeaker transmission line stuff.....
Model a 20 foot length of 100 ohm transmission line, with a 2 ohm load and a zero ohm source impedance. Give the line a prop velocity of .5C.
Apply a step function of 10 volts to the line via the source.
How long will it take for the load to reach 8 amperes? edit: oops, never...duh...I meant 80%, or 4 amperes.
The quick answer is that it will take longer that the time which humans have shown via repeatable test, to be sensitive to inter-aurally.
jn
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Guys, we've a bit of a disconnect here.
I am speaking about the settling time of the system for signals in the audio bandwidth.
gpapag is speaking of RF intrusion via the speaker wires.
Aurora believed gpapag was discussing the use of 1/4 wave to match speaker to amplifier at audio frequencies.
jn
I am speaking about the settling time of the system for signals in the audio bandwidth.
gpapag is speaking of RF intrusion via the speaker wires.
Aurora believed gpapag was discussing the use of 1/4 wave to match speaker to amplifier at audio frequencies.
jn
Ha ha.
Yes, I am concerned over RF issues at the line/load that may finally affect the amplifier
George
Yes, I am concerned over RF issues at the line/load that may finally affect the amplifier
George
The nominal impedance is for an infinite long line.
Nominal impedance is only correct at one frequency.
Transmission line effects are primary relevant at one quarter wave and more.
The wavelengths at audio frequencies are in the thousands of meters.
Therefore:
Transmission line characteristic impedance is totally irrelevant for AF. I really don't give a flying hoot if I could get a reflection back at 100Mhz.
Now, cable inductance, resistance, and capacitance are relevant. I would refer folks to the BELDEN site to see how these issues manifest themselves. These low frequency issues can and do get into the 30K to 40K region. As if they were important either unless you are in the habit of running a few hundred feet for your speaker cables. Excessive capacitive reactance can upset a badly designed amplifier, but usually amps don't mind the inductance.
RF at the load is irrelevant due to the driver inductance and crossovers.
RF at the source had better be irrelevant unless the amplifier design is so poor as to have no output network. I had an amp that bad once, bought Kimber cable to help it, then wised up and bought a much better amp.
If one is concerned with RF pickup, just twist the zip cord. You can get about 20dB rejection that way.
Nominal impedance is only correct at one frequency.
Transmission line effects are primary relevant at one quarter wave and more.
The wavelengths at audio frequencies are in the thousands of meters.
Therefore:
Transmission line characteristic impedance is totally irrelevant for AF. I really don't give a flying hoot if I could get a reflection back at 100Mhz.
Now, cable inductance, resistance, and capacitance are relevant. I would refer folks to the BELDEN site to see how these issues manifest themselves. These low frequency issues can and do get into the 30K to 40K region. As if they were important either unless you are in the habit of running a few hundred feet for your speaker cables. Excessive capacitive reactance can upset a badly designed amplifier, but usually amps don't mind the inductance.
RF at the load is irrelevant due to the driver inductance and crossovers.
RF at the source had better be irrelevant unless the amplifier design is so poor as to have no output network. I had an amp that bad once, bought Kimber cable to help it, then wised up and bought a much better amp.
If one is concerned with RF pickup, just twist the zip cord. You can get about 20dB rejection that way.
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