Let's discuss now who first started using Ohm's law in audio amplifiers.
Wavebourn
Sorry despite the smiley I don't get it, please elaborate.
Thanks
-Antonio
I guess I'm starting to like the term tail pole.
At first this was discussed with regard to slew rate effects which I still dont see the significance for typical discrete audio amplifiers.
But as some are really pushing the overall bandwidth of these amps, this additional pole will start to reduce phase margin.
Thanks
-Antonio
At first this was discussed with regard to slew rate effects which I still dont see the significance for typical discrete audio amplifiers.
But as some are really pushing the overall bandwidth of these amps, this additional pole will start to reduce phase margin.
Thanks
-Antonio
My point was, we did not give yet names and did not review yet who first used each of obvious solutions based on elementary laws of physics.
Where you will see the effects as well from a less-than-ideal current source is in common-mode distortion, including effects due to loading the signal source.
I prefer using Hartree-Fock methods with configuration interaction terms; that way, we really know where the electrons distribute themselves. That's far beyond most amateurs but it's what I use to win listening contests.
OK, I read through Solomon's paper. More of it makes sense than when I started. So I plugged in this extra resistor in my sample CCS SPICE models. In my 2mA circuits, I found a slight improvement in the source impedance, but I was expecting it to effect the consistency of the source over frequency, and it did not seem so. I saw no change in distortion. Model too simplistic? I did see that there seems to be a good range for this part, in my circuit, about 500 Ohms. Not enough to substantially reduce the drop across the CCS transistor(s) to allow lower voltage faster transistors like the 10K used in my Hafler. One part, many aspects.
My point was, we did not give yet names and did not review yet who first used each of obvious solutions based on elementary laws of physics.
Now, you are going against the entire basis for patent trolls! I am surprised some idiot has not filed for a patent for using Ohm's law. Either of them. Our stupid patent office would probably give them one.
Apple got a patent on "sleek design" for crying out loud!
It is somewhat frustrating to give a hint to rational circuit design that has been out there for almost 40 years, yet got so much 'flack' for putting it out there. I am usually not as 'helpful' mostly because of the time and effort to either explain in my own words, a number of subtle design decisions, or be faced with scanning a reference and attempting to put it up. Also, there is a range of readers, some with PhD's in engineering and most others with much less, down to just amateurs. For its clarity, this Solomon article is a rather 'lucky' find, in my opinion.
Dave started it, I just picked up where he left off.
BTW, my first use of those resistors in series with CCS was in the late '70s, the Eisenson mod of Dynaco preamps. And it wasn't new then.
Ordinary people may call it Kirchoff's Voltage Law, but it arises from the conservative nature (zero 'curl', hence potential is meaningful) of the electric field in the quasi-static approximation (low frequency, so no changing magnetic fields) which is appropriate to circuit theory.tvrgeek said:
See how confusing it is to give an existing well-understood concept a new name? And in this case the name was even better related to the underlying physics than the usual name.
I was lucky enough to catch James Burke giving a talk just the other day. He was describing our shift from "educated" to knowing more and more about less and less until you get to the point where no one understands you except yourself. I think that is when you get full professorship. He then points out many if not most of the great discoveries were not by the experts, but buy the more general educated who knew several experts.
Unfortunately he was too tired to take questions. He used a lot of energy in the talk and sad to say, not as young as he once was. I wanted to engage him in an implication he made about the next revolution. (as in agriculture, industrial, and he says next will be "plenty")
I have done pretty well being a jack of all trades, or at least of many. Not that I am ever going to make any great discoveries, but I most enjoy putting the pieces together I have gleaned from this thread.
- Status
- Not open for further replies.