I'm looking for schematic of "ultrafast audio amplifier (#1+#2)) and "Non slewing audio power". Both are by Giovanni Stochino, and was in Wireless world/Electronic world Mar 1996, p256, May 1996, p410, Apr 1997, p278 , Aug 1998, p633.
I dont have any of those magazine.
Could anyone tell me where I can download it?
I dont have any of those magazine.
Could anyone tell me where I can download it?
I don't think you can download it, but you can get back=issues here: http://www.softcopy.co.uk/mag/default.asp?dir=ew . Click on "audio".
Jan Didden
Jan Didden
Searching the forum for Stochino immediately resulted in the
following thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=157&perpage=15&highlight=&pagenumber=1
Although it seems not to be quite the original schematic, the
thread contains this link
http://www.soton.ac.uk/~apm3/diyaudio/Stochino_circuit.jpg
following thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=157&perpage=15&highlight=&pagenumber=1
Although it seems not to be quite the original schematic, the
thread contains this link
http://www.soton.ac.uk/~apm3/diyaudio/Stochino_circuit.jpg
Current feedback maybe?
http://homepages.strath.ac.uk/~cnbp111/amp1.html
http://www.diymania.net/pass/project/CF-Power.htm
http://www.analog.com/UploadedFiles/Application_Notes/492001115525484056221917334AN211.pdf
BTW: I have the Giovanni pages somewhere. I'm not sure if I have the article or just the schematics.
http://homepages.strath.ac.uk/~cnbp111/amp1.html
http://www.diymania.net/pass/project/CF-Power.htm
http://www.analog.com/UploadedFiles/Application_Notes/492001115525484056221917334AN211.pdf
BTW: I have the Giovanni pages somewhere. I'm not sure if I have the article or just the schematics.
Haah? Phase Accurate and AKSA can speak Indonesian? Where are you guys from? Have been here? Istrinya AKSA orang Jawa, dari mana? Thank you for the replies
The reason I'm looking for those articles is to see how can we make a fast amp. What is the key secret. Once I heard a direct comparison between Crown power amp and MC2 (MCsquare)professional power amp. MC2 gives better sound. In the spec, the MC2 is very fast, damping very high. When I took a peek inside it, the circuit is very-very simple compared to Crown. The components and output devices is not as many as first I tought will be. It is the best if I can get the MC2 schematic. But I think I will never get MC2 schematic, since it is a high price-running production amp, so I tried different schematic to study. Maybe they are using the same principle.
The reason I'm looking for those articles is to see how can we make a fast amp. What is the key secret. Once I heard a direct comparison between Crown power amp and MC2 (MCsquare)professional power amp. MC2 gives better sound. In the spec, the MC2 is very fast, damping very high. When I took a peek inside it, the circuit is very-very simple compared to Crown. The components and output devices is not as many as first I tought will be. It is the best if I can get the MC2 schematic. But I think I will never get MC2 schematic, since it is a high price-running production amp, so I tried different schematic to study. Maybe they are using the same principle.
I think the schematic in http://www.soton.ac.uk/~apm3/diyaud...ino_circuit.jpg is not a current feedback amp. It is ordinary voltage feedback amp.
Current feedback can make fast slew rate and high damping factor. But many dont like the sound it produces.
But is it the one that Stochino refer to "Ultra Fast Power Amp"?
Is it possible to make fast amp with ordinary voltage feedback?
Current feedback can make fast slew rate and high damping factor. But many dont like the sound it produces.
But is it the one that Stochino refer to "Ultra Fast Power Amp"?
Is it possible to make fast amp with ordinary voltage feedback?
Hi Lumanauw (or is that Pak Lumayan??)
Istri lahir di Semarang, kerja di KOWAD di Jakarta. Kita menikah di catatan sipil di sana tahun 1983.......
A very high damping factor has little influence on the sound.
Most loudspeaker drivers are designed for voltage drive; with current feedback they don't give their best.
Cheers,
Hugh
Istri lahir di Semarang, kerja di KOWAD di Jakarta. Kita menikah di catatan sipil di sana tahun 1983.......
A very high damping factor has little influence on the sound.
Most loudspeaker drivers are designed for voltage drive; with current feedback they don't give their best.
Cheers,
Hugh
Per, Hugh,
This has been the subject of heated debates in another thread. For me, if you control the output current wih feedback, you use current feedback by definition. If you control the output voltage with the feedback, it's voltage feedback.
HOW you insert the feedback signal in the summer stage (ususally the input stage) is realy a different issue for implementation. What IC manufacturers (really their marketing people) call CF opamp means that they insert the feedback signal in a low-impedance node (often the emitters of the input stage) but has - in my view - nothing to do with CF or VF. It really IS arbitrary: where do you draw the line as to what is a "low impedance node"? A current-starved emitter node may well have comparable or larger impedance than a strongly biased base input node.
But, I am aware that many of this audience, not hindered by historical perspectives, have a different opinion. So be it.
Jan Didden
This has been the subject of heated debates in another thread. For me, if you control the output current wih feedback, you use current feedback by definition. If you control the output voltage with the feedback, it's voltage feedback.
HOW you insert the feedback signal in the summer stage (ususally the input stage) is realy a different issue for implementation. What IC manufacturers (really their marketing people) call CF opamp means that they insert the feedback signal in a low-impedance node (often the emitters of the input stage) but has - in my view - nothing to do with CF or VF. It really IS arbitrary: where do you draw the line as to what is a "low impedance node"? A current-starved emitter node may well have comparable or larger impedance than a strongly biased base input node.
But, I am aware that many of this audience, not hindered by historical perspectives, have a different opinion. So be it.
Jan Didden
Per,
Let me be more specific. If you take voltage for feedback from a divider connected to the output of a power amplifier feeding a speaker, without regard for current, that is voltage feedback. This is, of course, the conventional arrangement, and it's the arrangement assumed by driver manufacturers.
If you take a voltage for feedback from a sense resistor in the voice coil circuit, then it is, ergo, current feedback. Of course, it takes the form of a voltage, which is then applied to the feedback node of the amplifier. This arrangement controls feedback on the basis of current through the voice coil, ignoring the spurious effects of back emf from the coil; only current is measured.
This latter is what I understand to be a current feedback amplifier. The confusion arises because the current sense function actually produces a voltage which is in turn used to control feedback. However, the distinctions are clear.
Strictly the magnetic circuit of the driver should be designed to accommodate one or other of these two feedback modes. In practice, of course, a mixture is often used. I recall once examining a Bazouki amplifier made in Athens which used selectable current feedback. This apparently palpably affected the tone of the sound on a musical instrument.
Cheers,
Hugh
Let me be more specific. If you take voltage for feedback from a divider connected to the output of a power amplifier feeding a speaker, without regard for current, that is voltage feedback. This is, of course, the conventional arrangement, and it's the arrangement assumed by driver manufacturers.
If you take a voltage for feedback from a sense resistor in the voice coil circuit, then it is, ergo, current feedback. Of course, it takes the form of a voltage, which is then applied to the feedback node of the amplifier. This arrangement controls feedback on the basis of current through the voice coil, ignoring the spurious effects of back emf from the coil; only current is measured.
This latter is what I understand to be a current feedback amplifier. The confusion arises because the current sense function actually produces a voltage which is in turn used to control feedback. However, the distinctions are clear.
Strictly the magnetic circuit of the driver should be designed to accommodate one or other of these two feedback modes. In practice, of course, a mixture is often used. I recall once examining a Bazouki amplifier made in Athens which used selectable current feedback. This apparently palpably affected the tone of the sound on a musical instrument.
Cheers,
Hugh
Jan and Hugh,
finally some people who have the same historical associations
as me. We discussed this recently in another thread. I had a
very hard time understanding the CFB concept due to the
terminology I had learnt from my textbooks.
Actually, my book doesn't even use these terms, it talks about
voltage/current sense, to tell what we sense at the output,
and voltage/current error, to tell what we sum at the input.
VFB/CFB has to do with the latter.
finally some people who have the same historical associations
as me. We discussed this recently in another thread. I had a
very hard time understanding the CFB concept due to the
terminology I had learnt from my textbooks.
Actually, my book doesn't even use these terms, it talks about
voltage/current sense, to tell what we sense at the output,
and voltage/current error, to tell what we sum at the input.
VFB/CFB has to do with the latter.
Christer,
There is an easy way to check this. If you short the output (making Vout = 0), and the feedback signal goes to zero, you've got VF. If you disconnect the load (making Iout = 0), and the feedback signal goes to zero, you've got CF. Unambiguous, no confusion, clear. Takes even care of cases with combined VF and CF.
Jan Didden
PS Sterling job in keeping JC in.
There is an easy way to check this. If you short the output (making Vout = 0), and the feedback signal goes to zero, you've got VF. If you disconnect the load (making Iout = 0), and the feedback signal goes to zero, you've got CF. Unambiguous, no confusion, clear. Takes even care of cases with combined VF and CF.
Jan Didden
PS Sterling job in keeping JC in.
Christer said:
For me there is no difference. Current sense means that you develop the feedback signal from a sense element (usually, but not necessarily, a resistor) in series with the load. Disconnect the load, the current in the sense element goes to zero, your feedback signal goes to zero, so this is CF (for me).
If you mean with "modern meaning" the use of the term "CF" for amps that insert the feedback signal into a low impedance node (whatever the definition of THAT is), then indeed we are talking about two different things.
Jan Didden
Jan,
OK, so you actually use the term CFB differently from how it
seems normally used today. Seems like a sure way to cause
confusion to me. Actually, I like the way my old textbook does it,
separating the sense and error parts, which gives us four
different combinations. Howver, that book did not at all use
the terms VFB or CFB, which gave me a hard time to figure
out which of the four combinations these referred too.
I now go by the definitions as given in e.g. the TI documents
SLOA21 and SLVA51, which were the ones making me finally
understand.
OK, so you actually use the term CFB differently from how it
seems normally used today. Seems like a sure way to cause
confusion to me. Actually, I like the way my old textbook does it,
separating the sense and error parts, which gives us four
different combinations. Howver, that book did not at all use
the terms VFB or CFB, which gave me a hard time to figure
out which of the four combinations these referred too.
I now go by the definitions as given in e.g. the TI documents
SLOA21 and SLVA51, which were the ones making me finally
understand.
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