As a Class D amplifier is not a sampled system (no sample handheld coin on), Nyquist / Shannon theorem isn't applicable - right!?
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Class D IS a sampled system, but exactly when it is sampled depends on the point at which the instantaneous input voltage crosses the triangle or sawtooth voltage it's being compared to. I'm looking at Figure 3 in post #180 and the red dots look like red herrings to me. A simple comparator circuit (the way most Class D operates, but I haven't looked closely at this thread), will cause the output to change when the input and modulation inputs cross (where the black lines of the input and triangle waveforms touch), which have varying times for both on and off points, unlike a "traditional" sampled system where the sampling time is set by a steady clock. But again I haven't followed everything in this thread, and just from glancing post 180 I'm not sure what's what here. That's a long post in a longish thread, not sure I want to take the time to try to understand what's going on here.
You're right, the Class D scheme is a non-uniform sampling system. For the simulation, I used a uniform sampling method to approximate its performance. After trying different approaches like interpolation and FIR filtering, the results show that this approximation works reasonably well.
I'll keep thinking about this, and if I come up with a better way to simulate it, I'll update the results. If you have any ideas, I'd love to hear them and give it a try!
During this holiday season, I participated in several demo sessions. Despite being compared against those well-known equipment and speakers, this amplifier module still received plenty of positive feedback. Many thanks to the audiophile friends who invited me to take part!
Would you be willing to be a little more specific? Was it #1?
Also, what is the best equipment it was compared to?
Everyone has different taste of the music, but I believe each person has their own No.1 in their heart. 🙂
It's the Class D module introduced in our post.
If we can gather a certain amount of interest (above 10 pairs), I will produce another batch and make it available for DIYers who want to give it a try.
If we can gather a certain amount of interest (above 10 pairs), I will produce another batch and make it available for DIYers who want to give it a try.
I am definitely interested.
Before I install the amplifier in my system, I need to see the EMI levels of the final product.
You could also summarise other specifications and show us a photo of the unit you would ship.... you talk about a few versions in this forum, so clarifying which one exactly you will be offering -> would help a lot.
Before I install the amplifier in my system, I need to see the EMI levels of the final product.
You could also summarise other specifications and show us a photo of the unit you would ship.... you talk about a few versions in this forum, so clarifying which one exactly you will be offering -> would help a lot.
thanks for your interest.
I am pretty confidence with the EMI/EMC due to the following reasons:
1, the frequency is about 3.2MHz, it avoids interference to the AM/FM radio theoretically.
2, the entire module is covered by the aluminum case, to prevent leakage.
3, 6 layers PCB is applied, with the small footprint of the board, believe the entire ground plane is at same potential.
4, the power input trace goes with low ESR caps as follow figure. it helps filter out most of the noise.
5, the self-resonant frequency of output inductor is about 27MHz, and NP0 filter caps (very good high frequency performance) is used to make sure the output is clear enough, especially for higher order harmonics.
the shipping unit is shown as picture below:
the size is about 84mm(L) x 54mm(W) x 12mm(H), it can provide 100W (RMS) over 8Ohm load and 200W over 4Ohm. The maximum current is designed as 15A. And there is some other unique design of the circuitry to ensure the high sound quality, which including:
1, full balance design, the tolerance of the resistor is 0.1% and 1% of the caps (NP0).
2, very high precise, frequency differential op AMP is used for the integrator.
3, very high-speed comparator chip.
4, special designed 3-order sigma-delta architecture.
5, instrument level voltage reference to provide the power of the op AMP and comparator.
6, no need input op AMP to pre-amp the signal, keep the signal transparent.
If you have any further questions, please feel free to let me know. However, please note that I may not be able to provide all the detailed performance parameters like a professional amplifier manufacturer. but I’ll do my best.
Designed a case for a Monoblock AMP, no rendering. appreciate your comments and suggestions.
front view
back view
top view
inside
front view
back view
top view
inside
As this seems to be reaching point commercial viability the relevant posts have been split off to here:
https://www.diyaudio.com/community/...le-the-motivation-and-story-behind-it.422970/
As with other projects, discussion of the actual design can still take place here, however all posts related to buyers and monies etc are to be kept in the Group Buy thread.
To thank everyone in this forum for their continuous support and encouragement for my project (94 messages and 90 thumbs up received), I plan to start a free headphone amplifier demo program, currently limited to North America. Here’s the plan I came up with. It might not be perfect, so if you have better suggestions, feel free to let me know...........................
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Moderator Edit. This continues in a new thread here:
Moderator Edit.
This new thread is split off from here:
To thank everyone in this forum for their continuous support and encouragement for my project (94 messages and 90 thumbs up received), I plan to start a free headphone amplifier demo program, currently limited to North America. Here’s the plan I came up with. It might not be perfect, so if you have better suggestions, feel free to let me know.
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Moderator Edit. This continues in a new thread here: Moderator Edit.This new thread is split off from here:
To thank everyone in this forum for their continuous support and encouragement for my project (94 messages and 90 thumbs up received), I plan to start a free headphone amplifier demo program, currently limited to North America. Here’s the plan I came up with. It might not be perfect, so if you have better suggestions, feel free to let me know.
- A...
Last edited by a moderator:
I came here to say “but that’s not feedbackless” but stayed for the awesome PCB and case design. Take my money! 😀
Another thread has been created for the 'Free Headphone Amp Demo Program' which is now here:
Moderator Edit.This new thread is split off from here:
To thank everyone in this forum for their continuous support and encouragement for my project (94 messages and 90 thumbs up received), I plan to start a free headphone amplifier demo program, currently limited to North America. Here’s the plan I came up with. It might not be perfect, so if you have better suggestions, feel free to let me know.
- A...
@njswede Thanks, if you want to try the AMP module, please add yourself in the buying list. Here is the group buys link:
https://www.diyaudio.com/community/...le-the-motivation-and-story-behind-it.422970/