Yes. They were called TELEGRAPH LINES before the phone companies started using them for telephony.
However that sort of impedance matching is only of importance when the line is behaving as a transmission line, or where the line length is about 1/10th the electrical wavelength.
At audio frequencies, a cable doesn't begin to behave as a transmission line until it's about a mile long.
se
I believe that's for the older air/pole types, all the telco services around here are driven 150. I have a 2km 'home made' loop in service in Whistler with 600:150 trannies either end, good for about +- 1 dB @ 18 kHz properly loaded.
Well if you're using a 50k potentiometer and driving 25 feet of cable with it, something no sane person would ever do, then I think your question was rather misplaced.
Sorry to disappoint you but I'm not galled at all.
So far you haven't demonstrated anything with regard to your claim, which you ultimately contradicted early on when you said that a preamp can better "control" the cable than a power amp driving a loudspeaker.
The only reason for this to be true would be the fact that a loudspeaker is a much lower impedance load than the more usual 10k and up loads you find on most gear.
Yet you claim a preamp is better able to "control" the cable when the load impedance is LOWER than the more common 10k and up loads.
If that is the case, then the power amp should be able to "control" the cable better still because a loudspeaker presents a load even lower than 600 ohms.
No one has yet to demonstrate audible differences even when comparing cheap cables to exotic cables.
You've done nothing to substantiate your argument except to hand-wave.
se
Yes. Specifically, telegraph lines which were strung across the country before the telephone came along. They typically used around 8 gauge wire strung on the poles spaced one foot apart.
That's why I keep telling these people that the "600 ohm standard" is an irrelevant, antiquated throwback.
se
Your mantra is wrong. Maximum transfer of signal is nonsense. Define "signal" and in which units you measure it.
Maximum transfer of power is the basic axiom. You need to go back to the college, to learn basics.
"Signal" is the information which you want to convey, as opposed to that which is not signal, which we generally refer to as "noise."
The unit of measure in the context of maximum signal transfer is volts.
Sure, if you're talking about transmission lines. But we're not.
In a transmission line, you want maximum power to be delivered to the load. Otherwise, what isn't absorbed by the load gets reflected back and you end up with reflection and return losses. Maximum power is delivered to the load when the source, line and load impedances are matched.
And to that end, early telegraphy and telephony used power ratios, expressed in such units as the dBm, or decibel milliwatt which has a reference of 1 milliwatt, i.e. 1 milliwatt = 0dBm.
But we're not talking about transmission lines here. The lines are too short and we don't have to worry about return and reflection losses. Instead, we worry about transferring maximum signal in terms of voltage, not power.
Maximum signal is transferred when the source impedance is ideally zero and the load impedance is ideally infinite. If the source impedance and load impedance were the same, you're throwing away half the signal for no good reason.
And to that end, we use voltage ratios, not power ratios, which are expressed in such units as the dBV which is referenced to 1 volt, or dBu, which is referenced to 0.775 volts.
And it's no coincidence that 0.775 volts corresponds to 1 milliwatt into 600 ohms. The dBu is used to correlate voltage levels to the power levels used in the old 600 ohm systems.
se
Are resistances zero, or infinite? Are they ideally linear? If you speak of some ideal world, you are right. If you speak of a real one - please go back to college.
No, I speak of everything: transfer between stages, units, boxes, buildings, singers and listeners, whatever.
I can amplify power using emitter followers and transformers. Emitter followers according to your definition don't amplify signal (they actually attenuate voltage), but as the result I can organize you such a way enormously huge voltage gain.
I have to admit, you read many books and articles, and remember well some very useful conclusions. But you need to learn basics in order to understand how to come to that conclusions, and how to use them properly.
Good luck!
SO which transfers better, voltage or current ? tubes or SS ?........
As long as you pretend to ask a serious question, I'll give you a serious answer: it depends. On much more than you think.
jd
Good evening !
Just out of curiosity, has your friend posted his point of view in this 3d ?
what is his nickname ?
Thanks and regards,
gino
Rule of thumb: if someone cannot explain in simple terms his why he has a certain point of view, it's probably not based on facts 😉
jd
I have been asking him repeatedly.
He assures me that he will at the first opportune moment.
He is very busy.
I don't know if you implying that "He" can not explain himself clearly and simply, I suggest you wait and see.
The replies, as of late, are interesting in this way.
The amount of debate regarding electrical conditions between various I/O terminations of pre amps/power amps and cables as a complete electrical condition or state, would have had me to believe that someone or many here could matter-of-factually state as fact what the truth is.
In fact, I thought that there would be a recognized authority on the matter.
Am I missing something?
The Ohms Law reference doesn't seem to be debated, so if we have a site where electrical devices are built, should there not be a standard reference regarding the subject?
I'm not trying to cause division or hostility here, but from the view of someone (me or others) who are not trained in this subject matter, it is curious.
From my own experience in pro audio regarding low impedance balanced I/O and the cables I have used, here is what I've found:
Most systems that I've used do not have outputs and inputs @ 600 ohms.
In fact they vary anywhere from about 100-to-300 ohms at output to 300-to-2,000 or so at input, some times expressed as x ohms per leg-pin or side.
There are exceptions of course.
To be fair, most of the time, cables (XLR/TRS) are not swapped or auditioned rather they are usually selected based on their build quality, especially the connectors.
Most of the stuff I've used features Neutrik connectors, Canare, Belden cabling and others.
The majority on I/O terminals are of the electronically balanced type circuits and very seldom are they truly mirrored balanced circuits.
After viewing the replies about the above, I see that probably it would be a good idea to have a clear and authoritative statement on this matter and to use this knowledge when evaluating balanced equipment/cables.
Very seldom are cables and the connected equipment's electrical conditions discussed, they just seem to work.
But, this doesn't mean that a proper understanding won't benefit that industry.
One final thought.
In top-level mastering/recording studios and manufacturers of highly regarded equipment, this is a topic of discussion.
I just don't know if it is debated as such.
PSW Recording Forums is certainly the place to bring this subject up as there are a large number of internationally respected designers, recordists, producers, etc.
Perhaps, if no one is able to conclude this topic, it would be interesting to take the thoughts expressed here and post it over there.
The amount of debate regarding electrical conditions between various I/O terminations of pre amps/power amps and cables as a complete electrical condition or state, would have had me to believe that someone or many here could matter-of-factually state as fact what the truth is.
In fact, I thought that there would be a recognized authority on the matter.
Am I missing something?
The Ohms Law reference doesn't seem to be debated, so if we have a site where electrical devices are built, should there not be a standard reference regarding the subject?
I'm not trying to cause division or hostility here, but from the view of someone (me or others) who are not trained in this subject matter, it is curious.
From my own experience in pro audio regarding low impedance balanced I/O and the cables I have used, here is what I've found:
Most systems that I've used do not have outputs and inputs @ 600 ohms.
In fact they vary anywhere from about 100-to-300 ohms at output to 300-to-2,000 or so at input, some times expressed as x ohms per leg-pin or side.
There are exceptions of course.
To be fair, most of the time, cables (XLR/TRS) are not swapped or auditioned rather they are usually selected based on their build quality, especially the connectors.
Most of the stuff I've used features Neutrik connectors, Canare, Belden cabling and others.
The majority on I/O terminals are of the electronically balanced type circuits and very seldom are they truly mirrored balanced circuits.
After viewing the replies about the above, I see that probably it would be a good idea to have a clear and authoritative statement on this matter and to use this knowledge when evaluating balanced equipment/cables.
Very seldom are cables and the connected equipment's electrical conditions discussed, they just seem to work.
But, this doesn't mean that a proper understanding won't benefit that industry.
One final thought.
In top-level mastering/recording studios and manufacturers of highly regarded equipment, this is a topic of discussion.
I just don't know if it is debated as such.
PSW Recording Forums is certainly the place to bring this subject up as there are a large number of internationally respected designers, recordists, producers, etc.
Perhaps, if no one is able to conclude this topic, it would be interesting to take the thoughts expressed here and post it over there.
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Well, I don't want to be sarcastic, really not, but on the ins and outs of 'electrical conditions or state', someone already has, but it has been ignored.
I'm sure you realise that the question "what is better, ss or tubes" cannot be answered in a meaningfull way except with a several page explantion of the 'it depends' factors?
jd
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