Global Feedback - A huge benefit for audio

Anyone here listen to music anymore? :/.

There are of course more than 101 ways to skin a cat, the best are able to make any topology they are passionate enough about sound good. I notice we are on to crossover distortion, in relation to gnfb I feel relying on gnfb to eliminate this is a very poor choice sonically. How do we eliminate crossover distortion?, There are many options, and yes some sound better than others, I for one bet my ears on adaptive bias non switching class a for effortlessly beautiful sound, what's your choice?. Damn those buggers like me that listen to music!.


Colin
 
adaptive bias non switching class a

Colin

Like this?

161026d1267729344-new-class-super-non-switching-need-revival-pioneer-non-switching.jpg
 
So, what kind of crossover distortion type things happen in class d? Things that make distortion go high as signal level decreases toward zero? If there are lots of such, as stated.
When the output stage is in a high-impedance state ('dead-time') the commutation current through the inductor will determine if the output is pulled high or low. The result is that below a certain output current the gain is higher, similar in character to what happens with a Class AB amp operates in Class A at small signals.

Pretty good article about it here (refer page 9):
http://www.irf.com/technical-info/appnotes/an-1071.pdf
 
Another thing is the the comparator In class D... Which produces the PWM as a Product of the reference signal and triangle generator fixed or derived from the outputstage. If This comperator sets a second barrier for quality.

By the Way burmester integrated AMP with class D output is just a copy of one of IRF reference design with very few changes to it. The board is not fully populated...


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Anyone here listen to music anymore? :/.
Colin
All the time, but not when I am working---it is too distracting.

I had a hankering for the Schubert No. 14 "Death and the Maiden" string quartet yesterday. My Emerson Quartet recording on a DGG CD, to which I'd listened a few time before, has developed an astonishing amount of difficult-to-describe distortion, almost totally garbled, yet the rhythm and rough intonational contours are there and enough to make the piece recognizable (if you know it to begin with). Player independent. Disc looks o.k.

But I found another disc with the piece so heard that today. 😀
 
All the time, but not when I am working---it is too distracting.

I had a hankering for the Schubert No. 14 "Death and the Maiden" string quartet yesterday. My Emerson Quartet recording on a DGG CD, to which I'd listened a few time before, has developed an astonishing amount of difficult-to-describe distortion, almost totally garbled, yet the rhythm and rough intonational contours are there and enough to make the piece recognizable (if you know it to begin with). Player independent. Disc looks o.k.

But I found another disc with the piece so heard that today. 😀
Listening to No. 13, the "Rosamunde", now. Same quartet, the Endellion.
 
BCarso,


Awesome to see and hear!!. While I have a vast appreciàtion for the technology, if you don't listen to and or appreciate music one should get out of the audio game :/. Class D has had a numbers of years to mature now, how is the sound?, I may be wrong but the concept seems to be aimed 95% at efficiency of power and less about absolute sound?, correct me if I'm wrong. However in this modern day of pricier power I can understand this.


Colin
 
BCarso,


Awesome to see and hear!!. While I have a vast appreciàtion for the technology, if you don't listen to and or appreciate music one should get out of the audio game :/. Class D has had a numbers of years to mature now, how is the sound?, I may be wrong but the concept seems to be aimed 95% at efficiency of power and less about absolute sound?, correct me if I'm wrong. However in this modern day of pricier power I can understand this.


Colin
Certainly it's motivated by efficiency, primarily. But I've been surprised by how good some of it sounds. I'm not turning to it for my own listening, but I was fairly pleased with a small board two-channel amp to which I contributed, initially based on one of the IR driver chips and their FETs.

I'm inclined to class D for woofers for the efficiency. For compact sealed box systems with big-motored drivers and lots of low frequency boost, one can reproduce low frequencies admirably---well beyond my apartment SPL limits 🙂
 
The industry is so distorted and psychophantic that one very well known and current UK manufacturer markets products using nuvistor NOS tubes. I have heard it from more that one source that the tubes are not even in the circuit. Only the heaters are wired up.

This sounds very much like an urban myth! Nuvistors have metal cases and so the filaments would not be visible. I really doubt this happened; I have no doubt that the rumor (as indicated) got around.
 
This sounds very much like an urban myth! Nuvistors have metal cases and so the filaments would not be visible. I really doubt this happened; I have no doubt that the rumor (as indicated) got around.
I wonder if that was a reason MF migrated to the 5703, and dubbed it the "trivistor"? I think I almost threw the magazine across the room when I read about that 🙂
 
(maybe Mr Michaelson loathes audio mag writers/reviewers)
Well it's a tough job, the writing and reviewing, but someone has to do it. Or do they?

Nobody's perfect, but in a recent issue we have a ~40k$ speaker with a big dip in the on axis response, a modular integrated amp with a dual ultracapacitor bank power supply, charged by an a.c. adapter, that produces audible noise when switching banks, and with a lot of the modules measured and found wanting by JA*, and another loudspeaker with a high-frequency response with more peaks and dips than I've seen for quite a while---if they were narrower I'd suppose it was an electrostat.

And despite this we listen to music.

*(who gamely suggests that at least the system is modular, so the manufacturer will give a customer a relatively easy upgrade path when new and improved modules are available)
 
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