2092 resetting with crash cymbal

[FireLink]

Seen from the amp an LC output filter of a class-d amp looks like a series resonant circuit. Without load it would present a short-circuit at its resonance frequency. Fortunately the load resistor gives relief in this respect by damping it. You were talking about a load resistance of 4 Ohms. Is it a purely resistive load that guarantees damping at higher frequencies also ? Have you considered using a lowpass filter before the amp ?
What happens at lower frequencies ? I.e. does the amp behave similarily in cold and warm state at lower frequencies ? How hot do your inductors get after some time of operation ?

Regards

Charles

Yes, it is a purely resistive load, despite the cables(from board output to load) being aprox. 60cm long. The inductors get hot but I can still touch it, so it not as hot as the heatsink. With 1kHz sinewave I've got no ocp trigger, nor cold nor hot after an hour. At very low frequencies I got bus pumping and then the voltage protections would trigger.

 

[FireLink]

It would be better to set the scope to display peak to peak volts on the blue channel. RMS is fine too. How it trips may depend on impending peak current, based on the input signal.

Also helpful to know what is the gain of the amplifier? IOW, how many peak amps into a 4R load is being demanded by the input signal?

When I measured the gain I was using a 1kHz sine wave. With a 0,520Vrms at the input I got about 19,2V at the output(with the 4ohm load), so a voltage gain of 36

 

[Markw4]

Okay. Looking at the scope waveform of the cymbal sound again, it looks like the there are some peaks a little more than +- 1v. Maybe one at -1.2v shortly before the trip. Times a gain of 36 would give -43.2v. If we take e^2 / R, we get about 1,866/4 = 467 Watts peak. Current would be 43.2/4 = 10.8 Amps peak. Does that sound reasonable for this amplifier?

 

[chienmort]

0dBFS is not the start of digital clipping in most modern dacs. Please see the article at: https://benchmarkmedia.com/blogs/application_notes/intersample-overs-in-cd-recordings#:~:text=Intersample Overs are a Common Occurrence in CD Recordings&text=This means that there are,peaks that exceed 0 dBFS.

As I tend to think in terms of digital mixers rather than DACs, I am right in that context. Of course you can exceed 0dBFS in a computer based DAW and High End DACs, but I would still argue it is bad practice, as sooner or later you will exceed the headroom of a piece of equipment.

 

[Markw4]

ITU standard is to use a reconstructed peak value. Modern loudness meters follow the standard. For example, like the one at: https://youlean.co/youlean-loudness-meter/
Or like this one: https://www.orban.com/freeorbanloudnessmeter

"1770-4 Integrated Loudness, EBU R 128 LRA, highest reconstructed peak level, and number of reconstructed peaks above 0 dBFS."

 

[FireLink]

Okay. Looking at the scope waveform of the cymbal sound again, it looks like the there are some peaks a little more than +- 1v. Maybe one at -1.2v shortly before the trip. Times a gain of 36 would give -43.2v. If we take e^2 / R, we get about 1,866/4 = 467 Watts peak. Current would be 43.2/4 = 10.8 Amps peak. Does that sound reasonable for this amplifier?

Hi. Very late answer but the problem was the undervoltage protection, cause I was using a improvised linear supply with 2 toroids that I thought it would be enough. Kinda hard to get this voltage drop on the multimeter, but whenever i remove the UV protection the problem is gone. Really appreciate all the answers.