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Roland68
Major Contributor
If you are looking for a cheap board then there isn't much difference anyway. Almost everyone uses the simple and cheap standard circuit from the TI data sheet and saves money there too. This also applies to the components, cheap output coils, cheap capacitors, cheap board material, etc. You just can't expect to find a $30-40 set of output coils on a $25-30 TPA3255 board.
A finished A7 or V3 for $50-60 with a case is more worthwhile.
Alternatively, you can do real DIY and order an empty circuit board from XRK Audio or order circuit boards from the TI Evaluation Board from a service provider and assemble them yourself. Then you have control over the costs and the parts yourself.
Will it be cheaper? barely. Time expenditure? You won't be done with this in a few hours.
The boards from 3e Audio and SylphAudio are well developed and equipped with high-quality components. Considering the quality and effort involved, these boards are not expensive.
PS: I played with 4 different cheap TPA3255 boards from Aliexpress, including a replica of the TI evaluation board. None of these come anywhere close to the PA5/II, the current boards from 3e Audio and SylphAudio, or the self-assembled boards from XRK Audio or the TI Evaluation board.
You get what you pay for, at least in this case.
It would be a really cool project to design a tpa3255 from scratch like Phil did with a less powerful chip. Unfortunately it goes well beyond my non existent knowledge.
Roland68
Major Contributor
I ruled out the board straight away because it uses an extremely cheap Blutooth chip as a solution for everything (DAC, ADC, digital volume control, etc.) and apparently also replaces the OPAmps.
This means that the analog signal is probably first converted into digital, then the volume is regulated and then converted back into analog. With a $1 chip like that? Oh well.
In addition, the entire area of voltage conversion for analogue 12V and digital looks even cheaper than usual.
But of course I could be wrong and the board might not be bad after all.
In any case, it would be interesting if you posted your experience and compared the amplifier with others.
That's why I asked for an opinion (post 1469) and I didn't get any opinion about that board,and when I bought that board I got an expert opinion.
The sound doesn't have to go through the BT chip, it can go directly.I can unsolder the BT chip if it causes a problem(that board is also sold without the BT chip)
I'm planning to get another 3255 board, so if I can, I'd like to hear your opinion
1.https://item.taobao.com/item.htm?spm=a21n57.1.0.0.4963523cMJEezt&id=616600822396&ns=1&abbucket=18#detail
4 channels dual 3255 and probably has XLR inputs
2.https://item.taobao.com/item.htm?spm=a21n57.1.0.0.4963523cMJEezt&id=758436017747&ns=1&abbucket=18#detail
dual 3255 stereo 600+600w
Thank you
Sorry from my english,i use Google translate
The sound doesn't have to go through the BT chip, it can go directly.I can unsolder the BT chip if it causes a problem(that board is also sold without the BT chip)
I'm planning to get another 3255 board, so if I can, I'd like to hear your opinion
1.https://item.taobao.com/item.htm?spm=a21n57.1.0.0.4963523cMJEezt&id=616600822396&ns=1&abbucket=18#detail
4 channels dual 3255 and probably has XLR inputs
2.https://item.taobao.com/item.htm?spm=a21n57.1.0.0.4963523cMJEezt&id=758436017747&ns=1&abbucket=18#detail
dual 3255 stereo 600+600w
Thank you
Sorry from my english,i use Google translate
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Roland68
Major Contributor
Be careful, it may be that it is not just a simple BT chip, but a universal chip with all sorts of functions, of which there are several in China.
This is also indicated by the 3-pin connection for the volume.
If you post pictures of the board without a heatsink, preferably of the top and bottom with readable chip labels, we could certainly say more about the board.
Can you tell me what you hope to get from these cheap boards?
@Matrix here they sell what it seems to be the same board than in your post #1484 with and without the bluetooth chip, what 1. suggest that the analog input does not go through the bluetooth chip 2. you dont need to desolder the bluetooth chip if you don't want it there, it already comes without it:
they also post some measurements. if they are to be trusted, i don't know.
Walter
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That depends somewhat on where you live.
Roland68
Major Contributor
Please read my previous posts again.
All cheap TPA3255 boards have the same cheap layout with the same cheap input circuitry.
This has nothing to do with components, because even if you use the best components in the world, these cheap TPA3255 boards won't even come close to the better and more developed TPA3255 boards like 3e Audio, SylphAudio, XRK Audio, or Topping PA5(II ) come. A lot of people have tried this (take a look at the various threads on diyaudio) and then end up with these boards.
If you are interested in pure DIY, then take the bare board from XRK Audio or have the TI evaluation boards made.
Many did not give up on those cheap 3255 boards, they are sold en masse and they are modded, the DIY forum is full. By changing some components, the sound improved a lot. The cheapest 3255 amplifiers Fosi V3, AZ3 etc and Aiyima a07, a07 max are also sold the most.
The price for XRK Audio ?
I ordered two more 3255 boards
The price for XRK Audio ?
I ordered two more 3255 boards
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I know this post was made a while ago. But there is no ionizing radiation involved with Electro-magnetic emissions. Heat generation is the only concern and yes IF it's at microwave frequencies - then there's a problem. But all the way up through 100 mHz there is absolutely no effect on biological tissue. No radiated emissions from an SMPS or a Class D amplifier will hurt you.
somebodyelse
Major Contributor
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I guess you'll be modifying the heatsink too, since those won't fit under it.
The wondom bdm9 have Sagami inductor and is little bit more expensive than bdm8 . U can go to line in direct to amp whithout dsp chip.
I looking many time to buy bdm8 or 9 and i think i buy bdm9 because have little bit more power.
I'm planning to buy a Sagami 7G23A or 7G23B on taobao, so I was wondering which inductor is better so I know which one to buy.
I bought bdm8 and I'm waiting for it to arrive from AliExpress
I also bought this board and I'm still waiting for it
€31.24 30%OFF | TPA3255 HIFI Power Amplifier Module Class D 4 Channel High-Power Digital Amplifier Board Sound Audio Parts
I bought bdm8 and I'm waiting for it to arrive from AliExpress
I also bought this board and I'm still waiting for it
€31.24 30%OFF | TPA3255 HIFI Power Amplifier Module Class D 4 Channel High-Power Digital Amplifier Board Sound Audio Parts
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Do you guys realize that it takes actual engineering to improve an amp's performance, not just replace random components for supposedly better ones?
Take for example these SMD to DIP adapters: they add a lot of inductance and move away the bypass capacitor way too far for comfort. In the worst case, you'll end up with an unstable situation and the thing oscillates.
Take for example these SMD to DIP adapters: they add a lot of inductance and move away the bypass capacitor way too far for comfort. In the worst case, you'll end up with an unstable situation and the thing oscillates.
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