I have first finish the circlotron, making a pcb after receiving parts, but newyear and christmas days did slow down a lot, but have interrests about class D, but in high end class and not kilowatts of power, but it is nice reading here, beautifull threat ehhh thread.
regards
This 9 is a rule of thumb, not carved in stone, but more-or-less correct. (Depending on very much factors about your hearing and the music, modulation method, etc... not to mention realisation imperfections.)
You can easily simulate a theoretical PWM signal and check its spectal density. With high modulation freq and amplitude Sw freq components are spread up and down to carrier freq exactly the way in case of Phase Modulation. The bandwidth of these side-bands is not limited in freq (unlike in case of AM), but continues down to 0 Hz with decreasing amplitude. The amplitude limit you choose for this disturbance determines the ratio of fsw and fmod. With about -100 dB limit you get something about 10. But this also depends on modulation method much! Natural and uniform sampling gives different result, not to mention symmetrical and asymmetrical PWM and self oscillating.
Actually in naturally sampled, symmetrical PWM you have 2 sample points in every PWM cycle...
230 kHz is usable for fullrange, however can be problematic if freq drops much near rails.
Last edited:
I know not sometimes!
It is very simple. Losses! Even I can smell it from here!
Do you mean you finally did the short circuit test, and your amp burned out? Im not surprised you can smell it.
The choke thanks and works fine for years.
Losses? Yes, you are simple indeed. What kind of? DC, eddy current, histeresys? You dont know. You tried once and it burned, this is why you think everybody fail using it like you.
Find it, it is 20 ohm and 1 ohm, these gate resistors are used to set also death time, but when using other mosfets it needs adjusting.
thanks for the hint.
Because instead of writing so much, they do not demonstrate their work, with photos with diagrams and PCBs (since diagrams is only theory) with video to listen to the sound quality. The people of this portal who follows them want to learn from you demonstrate what they know by teaching to make a good amplifier, this public that expects of you the best to extend your knowledge in practice not in theory, this portal is not so that some All those who are discussing, should be for hundreds or thousands of people who learn and expand their knowledge since they did not have the luck to be electronic but they like electronics like hobby as it says in the heading of DIYAUDIO proyects by fanatics, for fanatics.
So I hope this 2017 make a better world share our knowledge and teach everyone who wants to learn as he says "He who does not live to serve does not serve to live"
So I hope this 2017 make a better world share our knowledge and teach everyone who wants to learn as he says "He who does not live to serve does not serve to live"
My congratulations to Mr. Kartiño, Thienchay, Manojtm, Stewin, Jlester87 in the end to many who collaborate and for the progress achieved in the Amp Class D by the pdf, pcb, diagrams follow this and do not be selfish and share. Make a collective intelligence, many know, many believe to know, but in practice it demonstrates what we know
You are talking something you have no info about at all. As usual.
Again I can smell it from here!
Yes, that is what I smell
I dont smell an 150V 30A amp.
But a for fun amplifier with inductor hot like hell.
You don't listen, or intentionally state untrue. It is a precision, high power instrument, used as audio amp once for fun and regularly for science purpose. And never was hot like hell. Even when I tested it with intentional overload. Have you ever tested your amps with more current then the nominal continuously? Or at least with nominal? I bet not.
You asked me to show my amps, but your only purpose was to find something to pick at.
Are you joking? No such rule. Many people reported the opposite.
BTW you have so many untrue and meaningless or miswritten statements that would be very hard even to list.
I am very serious
Check Hypex UcD.
Bandwidth is even up to 35kHz.
This is a very basic knowledge
Hi,
See my schematic to get idea. Always find out why such schematic is deigned like that. I cannot tell very long theory BUT all components have been designed carefully.
Do you mean you finally did the short circuit test, and your amp burned out? Im not surprised you can smell it.
The choke thanks and works fine for years.
Losses? Yes, you are simple indeed. What kind of? DC, eddy current, histeresys? You dont know. You tried once and it burned, this is why you think everybody fail using it like you.
have you test your amp like this:
https://www.youtube.com/watch?v=r5k0uWBQogk
People should start from a rat repellent size before go to kWs size.
Yes it is.
To add data for my hypothesis about you
Again I can smell from here
You are not a good listener for a music quality.
Again pactice!
Heat in a core means losses, means saturation limit is too close at average output. And core will be saturated like hell in heavy load. Saturated core means non linear, means distortion, means crappy sound.
Inductor core is the most important part in class D, together with mosfet.
As Mr. Bruno said, no tricks but good part, the two parts are the most important.
And Micrometal T157 or similar with bigger size is the best core on planet for class D.
Pafi.. Pafi.. Pafi.... experience is priceless but you have ignored all from me.
Last edited:
Apologize me, that really I don't want to make a hard discussion in this forum.
However people should keep respect each other. Then the only we can continue to share and contribute.
thanks pafi
I totally agree with you at high volume trible frequncys make noisy
sssss ss sssss sss like AM radio
but my amplifier use only small PWM variation
power supply Is 80-0-80v amplifier use only 53v peak to peak around 40V (RMS) (because small 10inch speakers)
I test it using oscilloscop FFT ,minimum carrier frequncy drop around 200khz
200khz Is it possible
I feel no differnt between TDA7294 AB amp and this class D amp
sound quality same
Kartiño, patience and show what you know as you have done so far with diagrams, videos and if you can pcb in pdf, that speaks Well of you, more than a thousand words but share your knowledge here, in this community of electronics and amateurs. Many times the practice is worth more than theory, and this Amp Class D is an almost new technology must have more than a decade in which not much has been researched yet. And they are doing people like you, go ahead and share your knowledge for those who least know, on the way you will find many stones.
And Lords respect, that we have more or less age does not make us owners of the truth, we are here to share and learn.
And Lords respect, that we have more or less age does not make us owners of the truth, we are here to share and learn.
Yes, I test this way overcurrent protection (as demonstration to user) and also with continuous short, not just momentary, and my amps try to restart periodically. But I don't get such big sparks, since my protection is fast, it shuts down in 300 ns after current exceeds limit. And during real OC protection tuning I actually measure current by scope and check if it is correct for both positive and negative direction.
You think this was enough for protection, but it's not. Short circuit can not only happens when there is signal on output. Can you do the test I said?
Again you bluffing
That sparks come from dirty contact at high energy. I am an electrical engineer of biggest electrical company in the world. My job is designing substation up to 500kV. Stop telling nonsense!
Last edited:
Yes it is.
To add data for my hypothesis about you
And during this you revealed how person you are. Not funny.
Again: learn writing! At least 3 errors in 2 words is too much for me to correct them.Again I can smell from here
You are not a good listener for a music quality.
Again pactice!
2 serious mistakes in 1 sentence (as usual). Losses doesn't mean saturation limit is close. You ignored both DC copper loss and eddy current loss. The other mistake is that you ignored that I tested it not at average level but at more than the rated current. With music none of my cores heats up more than 40 C above ambient, most of them do 2...10 C during real usage with max volume. And to check saturation limit I make other tests and calculations.
You are not a good listener for a forum. And no matter how you may surprised, this is a forum, not a concert hall. Here the only information is via sentences and attachments. You can't listen to sounds, you have to listen to sentences. But unfortunately you can hear only what can fit into your false generalisations based on your limited experience and almost nonexistent theoretical knowledge base.
Very reasonable... best in planet... I guess you tried all. You must be some smaller god.
Best core? You didn't even specify the material, only size! You can't believe material is not important! I know you think about the -2 material, but your imagination is so hardly limited that you don't think there are other options. Like molipermalloy, multi-gapped ferrite, etc. Have you ever tried to achieve (or to measure) Q factor over 200 at 200 kHz? Or optimizing for high power density instead of big size? Do you think big size is a goal? I guess yes. Your Lina amp is large. Not powerful, but large indeed, so the name is correct. The specification is less correct. 2000 W comes from it at stable power supply (big, expensive, not diy) with very high distortion and switching freq decreased to audible range. I never let a full-range amp to switch at audio freq. And I make nominal power available with about 1% THD at dropped power supply voltage. What you call 2000 W is 1200 W specified by me.
Pafi.. Pafi.. Pafi.... experience is priceless but you have ignored all from me.
Experience? Do you mean should I learn how to copy and paste? You shared no experience. You mostly implied (instead of explicitely stating) your false generalisations in badly composed and spelled sentences. Please list the occasion where you explicitely stated an experience? As I can recall your last post contained your only real experience (video showing sparks during OC testing). What else?
Experience is not priceless, it is the most expensive. It costs both time and money and mental effort. And an experience is personal by nature, it cannot really be shared. I can't take account your experience, since you told almost nothing about it.
You ignored the experience of the builder of your D900 schematic. Also my simulations. Also my explanation why changing input polarity is beneficial. And many-many other things.
I don't prefer sharing experience, because it is personal and specific, and very hard to transfer and interprete correctly. Theory and logic in contrast are able to be shared, and to be checked also. And (correct) theory makes possible to arrange the very high amount of experience into a usable structure that makes possible to predict the result of a future experiment. This way of thinking let humankind come out of the caves and bulding skyscrapers.
Last edited: