This is a recording of the amp with both channels running side by side: Zippyshare.com - class d recording.flac
I hooked the speaker outputs from the amp to the line input on my PC through a resistive voltage divider. The click in the beginning if the amp beeing turned on and the pop at the end is the amp beeing turned off.
Ppl on other forums have listened to it and all have reported really low noise, barely audible, which i can confirm, unless i put my ear within inches of the tweeters, i cannot hear any noise what so ever.
Only mods needed are depicted in this schematic, the 100ohm resistor and the 1nF cap:
I hooked the speaker outputs from the amp to the line input on my PC through a resistive voltage divider. The click in the beginning if the amp beeing turned on and the pop at the end is the amp beeing turned off.
Ppl on other forums have listened to it and all have reported really low noise, barely audible, which i can confirm, unless i put my ear within inches of the tweeters, i cannot hear any noise what so ever.
Only mods needed are depicted in this schematic, the 100ohm resistor and the 1nF cap:
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Tekko
At the moment im studying compensation networks type 1, 2 and 3 and poles and zeros (the control loop math seems very challenging but i get the just of it)
Looking at your latest version I don't see any form of compensation network, the funny part of self-oscillating class-d amplifiers are they are intentionally made to "oscillate" based on the assessment i would think a compensator would be also be introduced to make the control loop stable maybe just after intended target frequency create a pole to control frequencies in the higher frequency spectrum from entering the loop thus improving loop stability.
(of course one that does not effect the target self oscillating target gain and phase margin)
Also another improvement would be to wire the input as a differential mode instead of common mode, noise would also be reduced.
Anyone here can shed some light on the subject would be great.
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This one is modeled after the philips UcD PDF which did not have the passive pole depicted in one of the hypex white papers.
And i never use zobel links in my amplifiers as i feel the zobel like it a bit of a bandaid put on amplifiers that have a habit of oscillating under certain conditions such as driving capacitive loads or beeing ran open circuited, i this case the zobel act as a load at higher frequencies.
If i want the passive pole i can simply move the 11k resistor from where it currently is between speaker output and comparator input, to between speaker output and the point between the two 470ohm resistors where the 1nF cap connects.
Diff mode input have crossed my mind, i just havent felt like building a rca to XLR converter buffer yet.
However as it is right now my amp is 100% stable and noise is about the same level and kind as that on a class AB amp running with wide open volume.
And i never use zobel links in my amplifiers as i feel the zobel like it a bit of a bandaid put on amplifiers that have a habit of oscillating under certain conditions such as driving capacitive loads or beeing ran open circuited, i this case the zobel act as a load at higher frequencies.
If i want the passive pole i can simply move the 11k resistor from where it currently is between speaker output and comparator input, to between speaker output and the point between the two 470ohm resistors where the 1nF cap connects.
Diff mode input have crossed my mind, i just havent felt like building a rca to XLR converter buffer yet.
However as it is right now my amp is 100% stable and noise is about the same level and kind as that on a class AB amp running with wide open volume.
zobel filter???
I wasn't talking about any "zobel filter" i was talking about "frequency compensation" and my point was adding stability not "band stopping anything"
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