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Class D Switching Power Amplifiers and Power D/A conversion

what D amp give best sound.
what D amp give best sound.
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Old 2nd February 2018, 11:35 AM   #181
kees52 is offline kees52  Netherlands
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Same schematic now with excessive dead time, deadtime generator capacitors are 1 nF.

Question, I need a dead time generator for the IR 2110 what is the best way, a nand port, or buffers with schmitt triggers, (output buffer schmitt trigger and input normal buffer).

inverting is not needed, just switch the signals do also.

For the current feedback, there is very much fase shifting, so much that when on 1 Khz is oke and promissing but on 20 Khz the fase shift is so much that the feedback get lost and the input opamp get clipping including the current opamp.

So the current feedback has work on it, to find out how it work best so I go read some papers about motor inverters who use capacitor feedback, it is a very nice idea to get good measurepoint there, it is a very precise feedback point, the low pass however is a bad fase shifter, maybe a bessel lowpas 24dB octave can be used these have liniair fase shifting, a Rc bessel allpass filter can correct the feedback.
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Last edited by kees52; 2nd February 2018 at 11:41 AM.
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Old 8th February 2018, 07:53 PM   #182
selwe is offline selwe
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Excuse me for interrupting, but I was wondering if TPA32xx is a solid competitor and how does it compare with the list mentioned on the first page of this thread.
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Old 9th February 2018, 12:17 PM   #183
kees52 is offline kees52  Netherlands
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Some updates with current sensing feedback.

As fior now I did let it work from 20 to 20Khz or higher when low pass is higher.

I have disconnect the voltage feedback completely but can be reconnected and tuned for double feedback.

Last two pictures you see distortion, one low one high with only oneven harmonics. These are because of the diff current feedback common mode error, we need a good opamp with very high bandwidth, a video current feedback type do well, I have also did a schmitt trigger before the feedback, but if these are of help I do not now, I do now, it go from 20 to 20Khz without a problem.

Seems that fase shift do also get quite in line, making voltage feedback work better when use it together with current feedback.

regards



regards
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Last edited by kees52; 9th February 2018 at 12:23 PM.
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Old 11th February 2018, 11:48 AM   #184
kees52 is offline kees52  Netherlands
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Open circuit and square, it looks like the coil get nicely into the loop, because the overshoot is sompletely gone, with a voltage feedback I get overshoot without extra measures.

So this looks like it works, and I have here complete coil current feedback, and no capacitor.

The distortions you see is with highest HD double feedback, current and voltage, the lowest HD is with only current coil feedback, last picture is without load, then output voltage shoots up, and down but not big currents in output stage.


regards
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Last edited by kees52; 11th February 2018 at 11:53 AM.
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Old 11th February 2018, 11:52 AM   #185
kees52 is offline kees52  Netherlands
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IMD test, I do not now if this can be simulated, I have put two voltage sources, one 60 hz and one 7 Khz, 60 hz 1/4 output of 7 Khz, as I did read.

if it is oke, then IMD is also very low. But only if this will work, maybe I think it is low because of this way it can not be measured.
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Old 13th February 2018, 10:41 AM   #186
djfelix is offline djfelix
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Quote:
Originally Posted by selwe View Post
Excuse me for interrupting, but I was wondering if TPA32xx is a solid competitor and how does it compare with the list mentioned on the first page of this thread.
Im also interested how can TPA 32 compare with others
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Old 14th February 2018, 03:37 AM   #187
Nanoloop is offline Nanoloop  Hong Kong
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Quote:
Originally Posted by jencelo View Post
Go with TPA TI amps. I think they sound wonderful! They are dirt cheap too. Nothing to lose here. I cannot wait to have the new TPA3255 which is little bit more expensive but not much.
Surprised there's only one mention of the TPA325X amps in a thread about best class D - the TI EVMs are definitely the best class D amps I've heard - beats TK2050, TA2020 and TPA3116. I've not listened to the Hypex UcD though.
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Old 14th February 2018, 11:53 AM   #188
kees52 is offline kees52  Netherlands
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If we all go buy ready made electronics then this forum stop to excist, included the fun, it is just the challence to experiment and build electronics and learn.

For as quality the tube mosfet hybrids do still sound the best, I have not yet build the class d, but maybe a open loop with air coil and oil capacitor and see what happens. Need to make a lineair as possible sawtooth, maybe digital programmed.

regards'

Last edited by kees52; 14th February 2018 at 12:21 PM.
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Old 15th February 2018, 11:41 PM   #189
Tibouchina is offline Tibouchina  Australia
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Thumbs up The Nerd Gene will always survive!

Quote:
Originally Posted by kees52 View Post
If we all go buy ready made electronics then this forum stop to exist.
The Nerd Gene will always survive! There will always be a place for tinkers to gather and share ideas.

You may find the Class D development conducted by Captain Sensible of some interest.

See: DIY Class-d amplifier based on SODA, using HIP4080A

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Old 16th February 2018, 01:56 AM   #190
abraxalito is offline abraxalito  United Kingdom
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Quote:
Originally Posted by kees52 View Post
If we all go buy ready made electronics then this forum stop to excist, included the fun, it is just the challence to experiment and build electronics and learn.
I buy a whole lot of ready made electronics. Starting with a board and then modding the hell out of it is the best way to learn how to design for oneself that I've found. So my motto has become 'never leave it stock!'.

On TPA3255 I've been playing with the cheapest ready made board (258rmb on Taobao so around $40) and in stock form it was OK to good but nothing special. Modded though (attention going to power supplies firstly) its about the equal of an equally heavily modified TDA8932 board - but has greater power capability. Which is really, really good. I'll explore whether the (considerably more expensive, even with discount) TI EVM has employed some circuit tricks which have been left off this board.
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