Ncore refinement might measure well:
“prototype Lyngdorf 8 x 400 Watt class D amplifier based a new patented class D amplification technology which is the brainwork of my co-founders of Purifi Audio, Bruno Putzeys and Lars Risbo. This is the first of any class of audio amplifier which is completely indifferent to frequency, level and impedance variations. The actual performance is difficult to measure due to limitations to even the best test equipment (AP555). But we are specifying max 0,00015% THD+Noise, at ANY frequency 20-20KHz at 100 W/4 ohms. Intermodulation distortion WAY below any other technology. Notice the output impedance - scaled in micro Ohm!” Peter Lyngdorf
EDIT: see Bruno's post
“prototype Lyngdorf 8 x 400 Watt class D amplifier based a new patented class D amplification technology which is the brainwork of my co-founders of Purifi Audio, Bruno Putzeys and Lars Risbo. This is the first of any class of audio amplifier which is completely indifferent to frequency, level and impedance variations. The actual performance is difficult to measure due to limitations to even the best test equipment (AP555). But we are specifying max 0,00015% THD+Noise, at ANY frequency 20-20KHz at 100 W/4 ohms. Intermodulation distortion WAY below any other technology. Notice the output impedance - scaled in micro Ohm!” Peter Lyngdorf
EDIT: see Bruno's post
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Likely not, agree they will be looking for payback.
Oddly, I suspect that the cost of the device won't be inherently large, in that this will, in essence, be a bunch of high power DACs with tolerance for supply rails being saggy.
Ok... there will be some cleverness as if I tried this, I would be looking for very high speed switching at the output which would either make it fail or be gruesomely inefficient. Or expensive or all of the above.
I will be very interested to see how they negotiated this trade off!
Oddly, I suspect that the cost of the device won't be inherently large, in that this will, in essence, be a bunch of high power DACs with tolerance for supply rails being saggy.
Ok... there will be some cleverness as if I tried this, I would be looking for very high speed switching at the output which would either make it fail or be gruesomely inefficient. Or expensive or all of the above.
I will be very interested to see how they negotiated this trade off!
The fully numerical amplifier is coming and it is counter to the DIY idea of adaptation. When the ICs are ready, we as DIYs have little other option than to implement them and use them "as is". We may not even have to worry about making good power supplies which may be integrated in the design.
On the other hand, I see a lot of members using vacuum tube amplifiers. That is hardly because they offer the lowest THD values or best linearity (I'm no expert) but is based on the appreciation of sound. Sound is in the end subjective and may not be fully coherent with electrical data.
In the past, we designed discrete amplifiers with ample possibilities for individual adaptation and variation. We have many members who still master that art but they will become less in numbers because it is really complex work. Then came the chip-amps and our concern was to assure the best operating conditions for the chip while we were limited by the chip design itself. The monolithic class D (and T) amplifiers give us little room to deviate from the concept described in the datasheet. We can concentrate on the power supply, the output filter and eventually the input adaptation but we are bound by the chip layout.
The fully numerical amplifiers will be very expensive for some years before the successful chip-sets are available. Then, when the chip-sets are available and the Asian production robots are ready, the price will drop rapidly. But at that time, humanity may have more serious problems to attend to than sound quality.
On the other hand, I see a lot of members using vacuum tube amplifiers. That is hardly because they offer the lowest THD values or best linearity (I'm no expert) but is based on the appreciation of sound. Sound is in the end subjective and may not be fully coherent with electrical data.
In the past, we designed discrete amplifiers with ample possibilities for individual adaptation and variation. We have many members who still master that art but they will become less in numbers because it is really complex work. Then came the chip-amps and our concern was to assure the best operating conditions for the chip while we were limited by the chip design itself. The monolithic class D (and T) amplifiers give us little room to deviate from the concept described in the datasheet. We can concentrate on the power supply, the output filter and eventually the input adaptation but we are bound by the chip layout.
The fully numerical amplifiers will be very expensive for some years before the successful chip-sets are available. Then, when the chip-sets are available and the Asian production robots are ready, the price will drop rapidly. But at that time, humanity may have more serious problems to attend to than sound quality.
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From looking at the output impedance and the author's name, there is probably monstrual feedback loop gain inside of this amplifier, like noone has seen before. Interesting if its DSP engine is prepared for integration of driver's motional feedback in order to definitely close control loop around whole playback system. Looks like serious thing at the development, not a toy for audiophiles.
@Windfore: agree, most probably multipole feedback loop(s)..
The caption under the 2nd graph says 'THD' but the graph Y-axis label says 'THD+N'. I guess it actually is THD+N, because it gets lower at increasing power which is typical for THD+N. So the real THD will be even lower.
Jan
The caption under the 2nd graph says 'THD' but the graph Y-axis label says 'THD+N'. I guess it actually is THD+N, because it gets lower at increasing power which is typical for THD+N. So the real THD will be even lower.
Jan
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I searched United States Patent and Trademark Office for Putzeys Bruno/Inventor Name and Risbo Lars/Inventor Name. The Assignee Name for Risbo's recent patents and patent applications is Texas Instruments. His/TI's last one is in late 2018. The last solo patent by Putzeys is US 8,289,097; in 2012!
I am not versed in Class D. Hopefully, you can extract the patent/application which describes Peter Lyngdorf's excerpt.
I am not versed in Class D. Hopefully, you can extract the patent/application which describes Peter Lyngdorf's excerpt.
You mention an internal feedback loop. Due to my ignorance regarding "DD" amplifiers I will ask, isn't it so that a numerical amplifier operates on a description of the input that is so (absolutely) precise as the input sampling allows and needs no feedback?
Evidently, motion feedback will require a feedback loop. But without motion feedback and with high precision input sampling, for me to see it is a matter of converting the PCM description into a PWM description and the job is done? Few uses post-filter feedback anyway. Evidently, both a very precise and fast A/D for input sampling and a fast high-resolution DSP for conversion are needed.
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I am not an expert in mixed signal systems control theory but I know that PWM power output stage will certainly need control loop in order to fully linearize and immune it from the load variables. Fast ADC feedback loop using digital signal processing is perfectly possible in acoustic frequencies and it is done already in more or less good way in some designs. For such sharp guys like them it will be piece of cake I assume...
Patent is like 'hey, I am here, please take a look at what I've done, feel free to copy and use it in your area where all rules can be obeyed.' 
If I patented something I also would like to not show it to everyone. Another issue is that today literally everyone can patent almost everything. Almost wherever you move there is already a patent for something. It leads to development curiosum. If breathing was patented would it be legit to stop you from breathing?
If I patented something I also would like to not show it to everyone. Another issue is that today literally everyone can patent almost everything. Almost wherever you move there is already a patent for something. It leads to development curiosum. If breathing was patented would it be legit to stop you from breathing?
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In some part of the amplifier the numerical data words have to be converted to analog values - voltage, current, time, able to drive low impedances with lots of watts. Think of class D on steroids. And to make that as linear as possible you probably can't do without feedback. Lots of it.
Jan
Patent is like 'hey, I am here, please take a look at what I've done, feel free to copy and use it in your area where all rules can be obeyed.'
Its a fine line. You don't want to give the competition any ideas, but you also don't want them to discover the thing themselves and the go into direct competition with you.
And of course, eventually the patent fight will be won by the party with the deepest pockets.
Jan
Would you so kindly explain or send me to a informative page which explain what fully numerical amplifier is ?
Thanks.
- Edit -
If you are talking about class D and PWM etc, then I'm good
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Okay, got it - PCM, Sigma-Delta etc etc. But do we really need digital amplifier these days, that is the question.
My 2 cents regarding the DD amp posted in Quantifying class A quality:
Not to hack this thread and do carry on debating the DD amp in general, but perhaps you Jan could shed some light on the question I had and reason for creating the thread.
Quantifying class A quality.
- Oneminde
Well I have seen measurements of Bruno's earlier feats which were more linear than a good class A amplifier. class A solves some issues elegantly but also has non-linearities of course.
So, much more important than the class of the amp is how competently it is designed. It is all about how little it subtracts or adds to the input signal while amplifying it.
Perfection doesn't exist.
Jan
So, much more important than the class of the amp is how competently it is designed. It is all about how little it subtracts or adds to the input signal while amplifying it.
Perfection doesn't exist.
Jan
Would you so kindly explain or send me to a informative page which explain what fully numerical amplifier is ?
Thanks.
- Edit -
If you are talking about class D and PWM etc, then I'm good
Yes, my intention was to limit to amplifiers where signal treatment is fully numerical, except evidently at the very output which today is PWM based but may become streams of charge pulses.
The advantage from a design point of view is that all treatment is through numerical manipulation such that any analog uncertainty is avoided.
You rightfully ask if such amplifiers are really needed and the answer from an audiophile point-of-view may be no. But, you are going to get them anyway because from a production point of view they are economically less risky to handle. Put the circuit together as described in the datasheet and application notes, eventually enter your own firmware and let the robots do all the work. The complexity will be very high but who cares as long as it is successfully captured in a few chips for robot mounting.
Evidently, the music sources will for long remain dominantly acoustic and need sampling. As long as we cannot enter the nerve system directly with electrical stimuli that are perceived as sound we will have to rely on our ears. My guess is that anything in-between these two analog states will in a foreseeable future be handled numerically only for mainstream consumer products.
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