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Class D Switching Power Amplifiers and Power D/A conversion

Class D vs Class AB
Class D vs Class AB
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Old 18th February 2016, 08:28 PM   #31
tonitonitoni is offline tonitonitoni  Croatia
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bad crosstalk? so use them in active biamp and no crostalk problem, and efectively more power available on bass channel as other channel is not loaded much with tweet. ofc i assume that both channels are mounted on same sink.
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Old 18th February 2016, 08:37 PM   #32
noah katz is offline noah katz  United States
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Quote:
Originally Posted by eriksquires View Post
So I've read, but the crosstalk was unusually high (poor) for these amps.
"Interchannel crosstalk:
> 80 dB at 1 kHz;
> 63 dB at 20 kHz"

seems adequate to me, unless your unit is way out of spec
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Old 18th February 2016, 08:50 PM   #33
eriksquires is offline eriksquires  United States
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Noah

No, just that compared to other stereo amps I see 70 db or better at 20kHz. As others have pointed out it's not really an issue. I had been wondering if improving this would improve the imaging, and it did not.

Toni:

Yep, you are correct of course, but don't want to suffer the other active complexities. An outboard crossover is as much as I'll do. I have enough sets of cables and interconnects.

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Old 3rd January 2018, 12:54 AM   #34
ErnestoFB is offline ErnestoFB  Brazil
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The TPA32xx series is much better in THD than the newest class AB products, like TDA7575
http://www.mouser.com/ds/2/389/tda7575b-957192.pdf
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Old 3rd January 2018, 07:46 AM   #35
FauxFrench is offline FauxFrench  France
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In my view it is not that simple.
The class D potential is shown by ICEPower and similar spin-offs. But, the price is very high.
Cheap class AB with very low THD can be found with TDA7850, TDA7294 and LM3886. Very good sound at an attractive price.
Some prefer valve sound.
The class D was mainly developed for commercial reasons (personal impression), in particular for portable electronics. Less cooling needed such that the amplifiers could be enclosed in the cabinets of sound-bars etc.
The problem of class AB heating is often exaggerated, in particular cost of the power ending up as heat.

Could "the best" amplifier be agreed upon, we would need much less (types of) amplifiers in this world and this forum would have much less to discuss.
For me it is like good whiskey: you can tell a much better from a clearly inferior, but, with two good ones it is a matter of taste.

TPA32xx is no doubt very good, but, can the market be persuaded to spend that much more money than what the TPA3116 can offer? The large majority of customers won't notice the difference unless in direct comparison.
TI can make the TPA32xx mainstream by lowering the price and it will replace the TPA3116/TPA3118 in many applications.

Last edited by FauxFrench; 3rd January 2018 at 07:52 AM.
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Old 3rd January 2018, 09:29 AM   #36
Kjeldsen is offline Kjeldsen  Denmark
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I don't agree that ICEpower and spin-offs are expensive.

This is Hypex - and remember you get all connectors available and a nice box. It's quite hard to build something with cheap chinese boards and same power, that is much cheaper, and can you find a used amp it's imposible. Why do we build - it's a fun hobby :-)

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Old 3rd January 2018, 11:01 AM   #37
KaffiMann is offline KaffiMann  Norway
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FauxFrench:
I have and have tried several different implementations of tpa3116, have not liked any of them. They are cheap, but if done right you are quickly approaching the price of a good tpa3250.
The tpa3250 is much better. There is no comparison. I consider the tpa3116 stuff to be over hyped, the tpa3250 on the other hand is a great starting point most people would be happy to live with.
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Old 3rd January 2018, 12:39 PM   #38
FauxFrench is offline FauxFrench  France
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Kjeldsen: For the link you provide, I agree, I would not call that expensive. I have seen some other high-end implementations at much higher prices.

KaffiMann: I agree that almost all will be happy with a TPA3250 board but most also with a TPA3116 board. The difference in price for DIY-fun - almost 10 times (admitted, with a better TPA3250 implementation). For my TPA3116/3118 boards I paid very little and they perform subjectively very well with a good power supply.
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Old 3rd January 2018, 01:09 PM   #39
KaffiMann is offline KaffiMann  Norway
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I am glad that the tpa3116 worked well in your application.
For my many attempts to like it, it was just not good enough in any setting. Tried with many different PSU's, including battery. I still consider it a bit hyped-up.

For instance the tpa3116 YJ boards are certainly value for money, but to get a bit of performance out of it, maybe change at least output filter coils, and get a half decent pre amp stage, + some power smoothing, potmeter and a box.

This is not much more expensive then:
FXAUDIO FX502SPRO TPA3250 Class D Digital Amplifier Hi-Fi Stereo Audio Power Amp | eBay

Seen it as low as 60.99$. Including good output filter coils, NE5532 pre-stage, some psu smoothing, and a power supply in case you do not own one from an old laptop. Difference in cost is very low, but you get a very good implementation of the tpa3250 vs a "needs a bit of work and it's not quite as good" tpa3116.

Edit:
People considering the tpa3116 are much better off with a cheap TDA7297 or two + a 12v 7ah or bigger battery and a small charger. And get a cmoy to use as a pre-amp.

Last edited by KaffiMann; 3rd January 2018 at 01:25 PM.
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Old 3rd January 2018, 03:29 PM   #40
FauxFrench is offline FauxFrench  France
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You are absolutely right in that if you buy the right finished product from Asia, do it yourself is not necessarily saving.
Some of these finished Asian products are, however, not perfect implementations either. Cooling may be an issue and power decoupling is not always sufficient. Often the output filter chokes are of decent quality and the signal capacitors foil.

The problem with buying a finished product is that you learn much less about the product than if you construct it yourself, at least in part.
I have got a Marantz, a Denon and a Harman-Kardon amplifier but they are rarely used because I love my 10+ open-frame DIY amplifiers more. I invested time in making them and thinking about improvements. All what I use today are open modules where I constantly try new combinations and improvements in order to get a really good feeling of their nature.

After electronic production in large scale left Europe, my impression is that young people do not have the fun we used to have from constructing our own electronics. It has simply become too cheap to bother. I hope to return this trend a bit by taking part on this forum.

You feel a kind of happiness when even your TPA3116 construction works, and you feel ready to go on with more challenging constructions.
One day young people, starting with the simple, may turn into new KaffiManns or Kjeldsens and can contribute on this forum.

Your levels are higher than mine. I just want to pass on the pleasure of making amplifiers work (well), even if better ones can be found. Also, my speakers are probably not up to your standards so I cannot hear the subtle details as well as you.

One day I may even buy a TPA325x board.
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