peranders said:
OK, peranders, is it possible that for once, this dumb banker could be right on this issue? is it possible that Charles and I, two persons of vastly different view / background, can agree for once something this simple? 🙂 Just think about it for a second.
As to how to define VFB / CFB, I would say that it is probably an issue of convention. there are clearly areas where it is hard to decide one way or the other: as it is hard to have voltage and no current, and vise versa.
I would just like to leave it at that.
Nelson Pass said:
Well, it could have been worse. A lot worse. They could have had Bob Carver in charge of the naming.
You know:
"Magnetic Field Amplifier" -- Admittedly it is an amplifier, but has nothing to do with "magnets", "fields", or "magnetic fields". Instead, it used switchable rail voltages (class G). I think he now calls it a "Tracking Downconverter", which is a little better (I guess).
"Asymmetrical Charge-Coupled FM Detector" -- Not really sure how this worked, but knowing Carver, you can be pretty sure that it had nothing to do with "asymmetry", "charge", or "charge coupling". But I believe that it actually was an FM detector of some sort.
Or the "True Subwoofer" that "broke" "Hoffman's Iron Law". Uh-huh. Right. (I think Bob may have invented "cold fusion", too.) This thing is just a resonant system tuned with the passive radiator. Doesn't break any known laws of physics, at least the last time I checked.
peranders said:
yes and no.
peranders said:
so maybe some modesty is in order? Rather than proclaiming everyone that they don't have a clue of what cfb is about?
peranders said:
what is the pattern?
peranders said:
if you did go through those links you had advised us to go through, you will see that there is a lot of room for discussion.
peranders said:
who said the quoted paragraph came from JLH? do you now think the author knew what s/he was talking about? 🙂 or maybe you didn't know what you were talking about when you proclaimed that others don't?
Be humble, be humble.
I have just split the thread (about currrent feedback) to here.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=36563
Please continue with the Hawksford topic. 🙂
Gentlemen, is here anybody who have some experiences with Hawksford's circuit ( except Nelson, Charles and me ) ? Theory is theory, but tree of life is green 🙂 .
Actually I have only tried it in simulations, not in real life. JonMarsh has made some amplifiers with the error correction circuit, and has made several postings about them. A search under his name with the key word "Cordell" should turn them up.
You can also go to his User Profile and in the upper right hand corner, click on Search for all post by this user to look at all of his (or anyone's) posts.Charles Hansen said:
Upupa Epops said:
I have just returned from Austria (the best music is live music: Graz - Stefaniensaal - L.v.Beethoven by Nikolaus Harnoncourt, Tripelkonzert and 8th symphony, Haydn's "clock symphony"). Anyway I am starting designing the PCB of the amp with NP-PMA error correction and hope to be ready with the amp in a couple of weeks.
Well, the circuit works as advertised, but to make a statement
about the sound is a little difficult, as all the rest of the
amplifier varies from case to case.
Typically people using it are also pulling out all the stops to
lower all the other forms of measured distortion, along with
lots of feedback, all of which really complicates the situation.
I don't know of an example of a really simple amplifier where
this form of correction has been applied. Perhaps somebody
should build one up.
about the sound is a little difficult, as all the rest of the
amplifier varies from case to case.
Typically people using it are also pulling out all the stops to
lower all the other forms of measured distortion, along with
lots of feedback, all of which really complicates the situation.
I don't know of an example of a really simple amplifier where
this form of correction has been applied. Perhaps somebody
should build one up.
Upupa Epops said:
Well...yes, but you already knew that.
http://www.diyaudio.com/forums/showthread.php?postid=330446#post330446
Steven
I think Malcolm ought to get out of his easy chair and entertain
us with his thoughts about how it sounds. 😎
us with his thoughts about how it sounds. 😎
Nelson Pass said:
I'm working on one, just the output stage to be used with an input stage in a non-global feedback power amp. I'll keep you posted. My first power amp design in 6 years. About time.
Jan Didden
Nelson Pass said:
I heard from his colleague that he usually has exploited thoughts of his students ... 😉
janneman said:
Tandberg produced an amplifier using an error correction circuit around a parallelled lateral mosfet output stage ( 2SJ 55, 2SK175 ) with a total of 8 devices, without global feedback, this was the 3009A power amp. This was reputed to sound good and boasted less than 0.05% THD 20 Hzm - 20 KHz, 200W into 8 ohms and a claimed output current drive capacity of 55A . Haven't actually listened to one myself though.
William de Bruyn
Pavel, this is the most tactless post. I prefer you shut up and stop spread a rumor. 😡
You can search his site, his list of papers and find that he wrote his papers on electronics alone, without any students. Moreover if you read the list of research graduates you will not find anyone whose research title was analog electronics.
Nelson Pass said:
Steven posted one here:
http://www.diyaudio.com/forums/showthread.php?postid=330446#post330446
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