This question is for the owners of this amp.
Is rare german amp from '80, and in this year they make a new version.(www.ABACUS-electronics.com)
Is rare german amp from '80, and in this year they make a new version.(www.ABACUS-electronics.com)
English: schematic diagram, German: Schaltplan/Stromlaufplan
here is the simplified schematic diagram:
http://www.abacus-electronics.de/files/ampino-prinzip.pdf
and here additional URLs:
http://www.abacus-electronics.de/files/info-ampino.pdf
http://www.abacus-electronics.de/files/info-60-120b.pdf
about
ABACUS electronics | ABACUS
I read:
ABACUS Schaltung: geheimnisvoll – aber nicht geheim
Die ABACUS-Schaltung mag zwar geheimnisvoll erscheinen, ist aber nicht geheim. Jeder der will bekommt bei ABACUS ein Schaltbild und Abgleichanleitung. Kostenlos! Bevorzugt als PDF, einfach per Email oder auf der ABACUS Homepage unter Downloads. Und wer sich daheim in der Bastelstube für den Eigenbedarf selbst einen ABACUS zusammenlöten möchte, mag das gerne tun; ABACUS hilft.
in english:
ABACUS topology: secretive, but not confidential
the ABACUS circuit may seem mysterious, but isn't confidential. Each user can order (without costs !) the schematic and adjustment instructions. Preferred as PDF attachement, send inquiry per e-mail. Anyone DIYer who would like to solder, will get appropriate support.
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this article from Joachim Rieder
"Aufsatz zum Thema Audio-Verstärker -
über die Arbeitsweise des Rieder-Verstärkers" ?
death links now over webarchive available
https://www.abacus-electronics.de/pub/media/wysiwyg/pdf/akademie-2.pdf
https://www.abacus-electronics.de/pub/media/wysiwyg/pdf/akademie-1.pdf
https://web.archive.org/web/20160611141445/http://www.abacus-electronics.de/files/ampino-prinzip.pdf
Wayback Machine
https://web.archive.org/web/20160322082525/http://www.abacus-electronics.de/25-0-ABACUS.html
https://www.abacus-electronics.de/pub/media/wysiwyg/pdf/akademie-2.pdf
https://www.abacus-electronics.de/pub/media/wysiwyg/pdf/akademie-1.pdf
https://web.archive.org/web/20160611141445/http://www.abacus-electronics.de/files/ampino-prinzip.pdf
Wayback Machine
https://web.archive.org/web/20160322082525/http://www.abacus-electronics.de/25-0-ABACUS.html
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This is my own design 
I've been using it for years now. The circuit is generic, but has MANY ADVANTAGES:
AMPLIFIERS FOR DYNAMIC LOUDSPEAKERS
If you've ever wondered what's so 'dynamic' about ordinary loudspeakers, you probably wouldn't think of it if you couldn't make the comparison between a tube radio and a transistor radio.
The tube radio, juxtaposed, has a much more detailed sound.
The speaker seems to play silky smooth and portray all frequencies equally well. The transistor radio, on the other hand, seems shrill and slightly scratchy. The details don't come out as well and you always seem to have to find the right combination of speaker and amplifier and that can be a lifetime task, as the hifi industry and all the forums prove ^.^
To add to the example, still the comparison with a 60s Germanium transistor radio:
This also has this particularly detailed sound. Also bass reproduction seems to be no problem at all. Bass and silk at the same time from one speaker.
The trick is that both tube radio and germanium transistor radio use a transformer to drive the speaker ;-P
A dynamic loudspeaker not only has its impedance curve, but the impedance changes permanently as soon as it moves. It's like trying to reach into a turning wheel.
As soon as it turns, it turns virtually by itself, but changes of direction cost power. It is not the voice coil that behaves inductively, but the whole electro-physical system that is supposed to transform current into mechanical motion.
A transformer receives current, stores it in the form of "energy" in the iron core, and this creates an inductive voltage at the output, which can be high or low depending on the impedance of the loudspeaker. If a tube amplifier is operated without a speaker, 10,000 volts can easily come out of it and then no one standing nearby is safe anymore That is why a tube amplifier must not be operated without load and why a tube amplifier has been unbeatable in resolution and dynamics.
An excellent music amplifier is designed as a current op-amp and can do exactly that even better. The transformer is basically replaced by a single resistor that measures the current.
The opamp circuitry does the rest, regulating the output current so that its silhouette matches the signal exactly.
In doing so, within the operating voltage limits, any possible
output voltage can be modeled, but the OP does not need to know this. It doesn't care It is only interested in that the I-frequency response remains linear. The U-frequency response then looks exactly like the impedance plot of the loudspeaker ^.^
The speaker current has hardly any THD, but the output voltage can be distorted (modulated) at will to achieve that! This is the trick.
The loudspeaker current flows through the measuring resistor all the same time and can also be used
as a controller for the OP. The effect happens instantaneously and completely analog with radio speed (speed of light divided by number of transistors, lol).
I built this machine many times, for my living-room and for my guitar-combo. Touchy and responsive and every speaker chassis seems to sound equally good. No harsh noise anymore. This is the first concept that makes the loudspeakers virtually un-locatable. There is only sound scape and a superb center Works best for broadband speakers or 2-way speakers with dead simple crossovers. The circuit looks almost too simple and works that way since 2017. But maybe someone here has experience in improving discrete operational amplifiers.
Best regards from Germany, Alexander
I've been using it for years now. The circuit is generic, but has MANY ADVANTAGES:AMPLIFIERS FOR DYNAMIC LOUDSPEAKERS
If you've ever wondered what's so 'dynamic' about ordinary loudspeakers, you probably wouldn't think of it if you couldn't make the comparison between a tube radio and a transistor radio.
The tube radio, juxtaposed, has a much more detailed sound.
The speaker seems to play silky smooth and portray all frequencies equally well. The transistor radio, on the other hand, seems shrill and slightly scratchy. The details don't come out as well and you always seem to have to find the right combination of speaker and amplifier and that can be a lifetime task, as the hifi industry and all the forums prove ^.^
To add to the example, still the comparison with a 60s Germanium transistor radio:
This also has this particularly detailed sound. Also bass reproduction seems to be no problem at all. Bass and silk at the same time from one speaker.
The trick is that both tube radio and germanium transistor radio use a transformer to drive the speaker ;-P
A dynamic loudspeaker not only has its impedance curve, but the impedance changes permanently as soon as it moves. It's like trying to reach into a turning wheel.
As soon as it turns, it turns virtually by itself, but changes of direction cost power. It is not the voice coil that behaves inductively, but the whole electro-physical system that is supposed to transform current into mechanical motion.
A transformer receives current, stores it in the form of "energy" in the iron core, and this creates an inductive voltage at the output, which can be high or low depending on the impedance of the loudspeaker. If a tube amplifier is operated without a speaker, 10,000 volts can easily come out of it and then no one standing nearby is safe anymore
That is why a tube amplifier must not be operated without load and why a tube amplifier has been unbeatable in resolution and dynamics.An excellent music amplifier is designed as a current op-amp and can do exactly that even better. The transformer is basically replaced by a single resistor that measures the current.
The opamp circuitry does the rest, regulating the output current so that its silhouette matches the signal exactly.
In doing so, within the operating voltage limits, any possible
output voltage can be modeled, but the OP does not need to know this. It doesn't care
It is only interested in that the I-frequency response remains linear. The U-frequency response then looks exactly like the impedance plot of the loudspeaker ^.^The speaker current has hardly any THD, but the output voltage can be distorted (modulated) at will to achieve that! This is the trick.
The loudspeaker current flows through the measuring resistor all the same time and can also be used
as a controller for the OP. The effect happens instantaneously and completely analog with radio speed (speed of light divided by number of transistors, lol).
I built this machine many times, for my living-room and for my guitar-combo. Touchy and responsive and every speaker chassis seems to sound equally good. No harsh noise anymore. This is the first concept that makes the loudspeakers virtually un-locatable. There is only sound scape and a superb center
Works best for broadband speakers or 2-way speakers with dead simple crossovers. The circuit looks almost too simple and works that way since 2017. But maybe someone here has experience in improving discrete operational amplifiers.Best regards from Germany, Alexander
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