It was me. https://goo.gl/photos/4XHyLk3uZjDfuRmHA
I'm working on improved version. Variant B can be driven by Class D as well.
Well I am looking at the Hypex NC250MP. The Hypex in deed has decent specs but better than a decent Class AB ? Not really. A decent Class AB offers at least another digit in the THD spec. e.g 0.000x %
I have found that even with Class AB there are profound performance differences that can easily be heard by even untrained ears and yet the specs were really good, like incredible dampening factor and great frequency response.
Such as these offered by Bryston, Denon and AudioNet failed miserably in direct comparison with older Class AB Technology. Newer Technology offered by brand name Technics such as GAN used with Class D offers horrible THD at 0.5% for only $US16500 a pop. Be my guest and enjoy this wonderful new Technology, I'll pass.
Not many actually dare to publish transient response data and charts, in particular the Class D folks. I guess they know why.
If you think that this technology is not good, please, just don't post here. I would like to have suggestion how to practically do that.
I ordered Class D amps with IRS2092S and I am not sure if this type is good enough to play a role of variable power supply. Do anybody know the gain an phase plot of the amp with this digital audio amplifier?
Damir
I believe there was a Technics/Panasonic with this type of scheme. (Class B or C amp driving low voltage supply for Class A stage).
Also similar, but different is the Carver Sunfire type amp - Best description is each supply is a class D amp with +7 or -7 Volts of DC offset. Great for high powered subs - probably needs tweaking to run full range.
Also similar, but different is the Carver Sunfire type amp - Best description is each supply is a class D amp with +7 or -7 Volts of DC offset. Great for high powered subs - probably needs tweaking to run full range.
Class A and power and high efficiency are mutually exclusive concepts.
Class C is only for RF circuitry in which a resonant tank rebuilds the sinusoidal voltage waveforms.
A good engineered class D amplifier, well filtered, can be less problematic than a standard fullwave rectifiers with input capacitor filtering.
Class C is only for RF circuitry in which a resonant tank rebuilds the sinusoidal voltage waveforms.
A good engineered class D amplifier, well filtered, can be less problematic than a standard fullwave rectifiers with input capacitor filtering.
Last edited:
I finally received Class D amp L-25D kit. Before I start to assemble this kit I have a question. As a phase and gain at high frequencies are very important I intend to connect the negative feedback after the inductor L1 to have better behavior less dependent to the load.
I know that some of you have more experience in Class D and specifically this one with IRS2092 amplifier driver, I appreciate suggestion on what I have to pay attention. Is it enough just to move NFB connection before inductor to the position after?
Attached mounting guide L25D with schematic
Damir
I know that some of you have more experience in Class D and specifically this one with IRS2092 amplifier driver, I appreciate suggestion on what I have to pay attention. Is it enough just to move NFB connection before inductor to the position after?
Attached mounting guide L25D with schematic
Damir
Dear Damir,
this is not trivial. You can't simply move the feedback of the Class-D amplifier after the filter without a complete redesign of the feedback filter and compensation network.
Check the very good thread from ChocoHolicI have build 8 channels of his LiteAmp - very good sounding amps!
BR, Toni
Hi Toni,
Yes I've read that thread, but it's not clear to me what more I have to do.
Maybe I can ask author of LiteAmp for suggestion.
BR Damir
I tried to send PM to ChocoHolic but PM storage is full, so I try this!
Hi ChocoHolic,
I have read your thread Lite Amp and would like that you take a look this thread you will see that I am trying to design Class A amp in combination with Class D amp as variable power supply. I bought the IRS2092 kit and want to move the nfb point after output inductor but as I am no very familiar with Class D amp I need a help. What I need to change more to make that amp working?
Do you know where to find LTspice IRS2092 model?
Thank you in advance,
Damir
Hi ChocoHolic,
I have read your thread Lite Amp and would like that you take a look this thread you will see that I am trying to design Class A amp in combination with Class D amp as variable power supply. I bought the IRS2092 kit and want to move the nfb point after output inductor but as I am no very familiar with Class D amp I need a help. What I need to change more to make that amp working?
Do you know where to find LTspice IRS2092 model?
Thank you in advance,
Damir
Most likely I would also go this path when ultimate signal fidelity is the master goal and at the same time high power with reasonable heat is requested.
On the other hand ultimate signal fidelity is not necessarily identical
to satisfying sound.
There are key factors in design, which define the sound character of an
amp more than stunning THD numbers.
I.e. something went right with the V1.5 of my 2kW amp (class D), because I always start to smile when listening to it. And I like it more than any class AB amp that I owned before. So far I am not fully able to nail this down in measurements, just partially.
The lite amp measures better, but my ears prefer the other one...
Project by project there grows a design know how for sound,
which is not always identical to pure EE considerations.
If you want to change standard designs with IRS2092 into a postfilter feedback design then the easiest way is to convert it into a copy of the LiteAmp.
That's most likely more attractive than investing some years in linear control theory and some more in non linear control theory.
Simulations including a behavioral simulation model of the IRS2092
you will find free for download in the LiteAmpThread.
Probably because it never clips, and handles complex loads (i.e. loudspeakers!) with ease.
I found the time to read a few posts at the start of your LiteAmp thread. It's clear that you really know what you're talking about.
Suggestions for good text books on the matter gratefully received.
Frankly speaking... since 30 years control theory is falling onto my feet
once and a while. But I did not find a single book, which appears attractive to me.
Typically they are not written with the intention to grow fundamental understanding. Most often it looks a little bit like settling formal methods
for something which normal horse sense cannot properly solve.
J. Lunze was not bad - if I remember right. But not English.
Below I am listing some papers beyond the standard IR application notes.
Also the Lunze Textbook about control theory is in the list, however most papers are about different topics of class D amplifiers, not specifically about control theory. Enjoy.
Bruno Putzeys:
'The Bits In-Between. An EE's Guide to Survival Between Microphone and Voice Coil'
On the occasion of the 123rd AES Convention, Oct. 6th, 2007
Bruno Putzeys:
'Master Class, Life on the Edge, A Universal Grammar of Class D Amplification'
On the occasion of the 124rd AES Convention, May, 2007
Lars Risbo:
'DISCRETE-TIME MODELING OF CONTINUOUS-TIME PULSE WIDTH
MODULATOR LOOPS'
AES 27th International Conference, Copenhagen, Denmark, 2005 September 2–4
Lars Risbo and Claus Neesgaard:
'PWM Amplifier Control Loops with Minimum Aliasing Distortion'
AES 120th Convention, Paris, France, 2006 May 20–23
Stephen Cox:
'Mathematical models for class-D amplifiers'
School of Mathematical Sciences, University of Nottingham, UK
Presented @: School of Electrical & Electronic Engineering
NTU, Singapore, December 2009
Stephen M. Cox and Bruce H. Candy:
'Class-D Audio amplifiers with negative feedback'
Kaspar Sinding Meyer:
'Minimizing distortion in self-oscillating switching amplifiers'
Oersted DTU Department for Electric Power Engineering
Under guidance of:
Michael Andreas E. Andersen
Mikkel Christian Wendelboe Høyerby
Kgs. Lyngby, July 24, 2006
Nguyen Tranh T.:
Selfoscillating Switching Amplifier
Patent No.: US 7,221,216 B2
May 22nd, 2007
J. Lunze:
Regelungstechnik 1
DOI 10.1007/978-3-642-13808-9_8,
© Springer-Verlag Berlin Heidelberg 2010
Bruno Putzeys:
Selfoscillating Class D Amplification Device
Pub No.: US 2011/0068864 A1
March 24th, 2011
..and the Kemp design:
The design of an analogue class-D audio amplifier using Z-domain methods
once and a while. But I did not find a single book, which appears attractive to me.
Typically they are not written with the intention to grow fundamental understanding. Most often it looks a little bit like settling formal methods
for something which normal horse sense cannot properly solve.
J. Lunze was not bad - if I remember right. But not English.
Below I am listing some papers beyond the standard IR application notes.
Also the Lunze Textbook about control theory is in the list, however most papers are about different topics of class D amplifiers, not specifically about control theory. Enjoy.
Bruno Putzeys:
'The Bits In-Between. An EE's Guide to Survival Between Microphone and Voice Coil'
On the occasion of the 123rd AES Convention, Oct. 6th, 2007
Bruno Putzeys:
'Master Class, Life on the Edge, A Universal Grammar of Class D Amplification'
On the occasion of the 124rd AES Convention, May, 2007
Lars Risbo:
'DISCRETE-TIME MODELING OF CONTINUOUS-TIME PULSE WIDTH
MODULATOR LOOPS'
AES 27th International Conference, Copenhagen, Denmark, 2005 September 2–4
Lars Risbo and Claus Neesgaard:
'PWM Amplifier Control Loops with Minimum Aliasing Distortion'
AES 120th Convention, Paris, France, 2006 May 20–23
Stephen Cox:
'Mathematical models for class-D amplifiers'
School of Mathematical Sciences, University of Nottingham, UK
Presented @: School of Electrical & Electronic Engineering
NTU, Singapore, December 2009
Stephen M. Cox and Bruce H. Candy:
'Class-D Audio amplifiers with negative feedback'
Kaspar Sinding Meyer:
'Minimizing distortion in self-oscillating switching amplifiers'
Oersted DTU Department for Electric Power Engineering
Under guidance of:
Michael Andreas E. Andersen
Mikkel Christian Wendelboe Høyerby
Kgs. Lyngby, July 24, 2006
Nguyen Tranh T.:
Selfoscillating Switching Amplifier
Patent No.: US 7,221,216 B2
May 22nd, 2007
J. Lunze:
Regelungstechnik 1
DOI 10.1007/978-3-642-13808-9_8,
© Springer-Verlag Berlin Heidelberg 2010
Bruno Putzeys:
Selfoscillating Class D Amplification Device
Pub No.: US 2011/0068864 A1
March 24th, 2011
..and the Kemp design:
The design of an analogue class-D audio amplifier using Z-domain methods
Unfortunately I don't speak or read German
Thank you for the list of papers etc. I've come across most of these before and join you in recommending them to others, especially the first two and the last one. I wasn't aware of the Stephen M. Cox and Bruce H. Candy paper though so that's brought a few more undiscovered papers to light for me (via its references and citations).
After some discussions in the LiteAmpThread I guess you would prefer a more constant loop gain and phase over the entire audio range.
Here a postfilter feedback version which would serve this design goal, however it will have much higher THD.
But I understood THD is not your concern, because the ClassD amp will only move the supply rails of the ClassA amp.
The attached version should be easy to mod from standard designs with IRS2092.
I have chosen low resistor values in the small signal area. From perspective of IRS2092 you could go for approx 3 times higher resistor values and 3 times smaller capacitances if your layout is good enough.
