Hello everybody,
I tried to keep track of all the information about the YJ-like tpa3255 blue board posted here and on the thread tpa3255-diy-discussion-design.
the board is this one:
TPA3255 Scheda amplificatore ad alta potenza 300 W + 300 W, amplificatore di potenza digitale HIFI DC48V classe D, amplificatore audio DC digitale da 20Hz a 20KHz: Amazon.it: Commercio, Industria e Scienza
There are some things i didn't understand: are there any problems with the opamps?
I bought this board because it looks like it' salmost the same of the one tested here:
Quick Look: A Generic TPA3255 Design
– QuantAsylum
and, for my intended application, this performace level is definitely good enough. especially considering that i am going to use a 36V supply that should remove that instability problem that is most likely due to the LM2575 which can't take a 50V supply.
The point is that i also read some posts talking about issues due some opamps which might be fake or stuff like that. This sounds hard to believe to me. Especially I don't understand why should any manufacturer lose any credibility faking a tl072 opamp that costs 13 cents if bought in large amounts. So i really hope i misunderstood.
Can anybody tell me something about these issues? did i misunderstand anything?
Did anybody test this kind of board as it comes from one of the many sellers with an oscilloscope?
I hope i didn't make too many question and believe me, i read dozens of pages on these two threads trying to sort this out but there is a lot ofinfo here and i got confused
Thank you in advance for any help!
I tried to keep track of all the information about the YJ-like tpa3255 blue board posted here and on the thread tpa3255-diy-discussion-design.
the board is this one:
TPA3255 Scheda amplificatore ad alta potenza 300 W + 300 W, amplificatore di potenza digitale HIFI DC48V classe D, amplificatore audio DC digitale da 20Hz a 20KHz: Amazon.it: Commercio, Industria e Scienza
There are some things i didn't understand: are there any problems with the opamps?
I bought this board because it looks like it' salmost the same of the one tested here:
Quick Look: A Generic TPA3255 Design
– QuantAsylum
and, for my intended application, this performace level is definitely good enough. especially considering that i am going to use a 36V supply that should remove that instability problem that is most likely due to the LM2575 which can't take a 50V supply.
The point is that i also read some posts talking about issues due some opamps which might be fake or stuff like that. This sounds hard to believe to me. Especially I don't understand why should any manufacturer lose any credibility faking a tl072 opamp that costs 13 cents if bought in large amounts. So i really hope i misunderstood.
Can anybody tell me something about these issues? did i misunderstand anything?
Did anybody test this kind of board as it comes from one of the many sellers with an oscilloscope?
I hope i didn't make too many question and believe me, i read dozens of pages on these two threads trying to sort this out but there is a lot ofinfo here and i got confused
Thank you in advance for any help!
Hi
did you look at the beginning of the thread? Did you look in any pages and read something?
here it starts: i got a lot of help and i learnt a lot..
https://www.diyaudio.com/forums/class-d/309813-wrong-tpa3255-21.html#post5447118
chris
did you look at the beginning of the thread? Did you look in any pages and read something?
here it starts: i got a lot of help and i learnt a lot..
https://www.diyaudio.com/forums/class-d/309813-wrong-tpa3255-21.html#post5447118
chris
Hi Chris,
I read more than something, don't misjudge me, i am the kind of guy who reads
and I alreadey read some tens of pages from page 21 on. obviously, being it a forum, information is somehow fragmentated and you always risk to lose some pieces. this is why i am doing questions.
It's just that i didn't have time to read all this and the other thread about tpa3255 several times so to tidy up the info in my mind, these are hundreds of pages.
By the way, i have lost track of some things, this is the one i am more curious about:
What is wrong with TPA3255? , posts number 463 and 464, do you remember which board do they refer to?
in post 491, page 50, you say it was because of some fake opamps but since i wasn't able to understand which board does these measurements refer to, i didn't understand if this thing is relevant to me, but if it is, i will have to address the thing.
I hope you won't find my questions inappropriate anymore
Sergio
I read more than something, don't misjudge me, i am the kind of guy who reads
and I alreadey read some tens of pages from page 21 on. obviously, being it a forum, information is somehow fragmentated and you always risk to lose some pieces. this is why i am doing questions.
It's just that i didn't have time to read all this and the other thread about tpa3255 several times so to tidy up the info in my mind, these are hundreds of pages.
By the way, i have lost track of some things, this is the one i am more curious about:
What is wrong with TPA3255? , posts number 463 and 464, do you remember which board do they refer to?
in post 491, page 50, you say it was because of some fake opamps but since i wasn't able to understand which board does these measurements refer to, i didn't understand if this thing is relevant to me, but if it is, i will have to address the thing.
I hope you won't find my questions inappropriate anymore
Sergio
Hi Sergio
Sorry for my rude words...
here is the solution:
https://www.diyaudio.com/forums/class-d/309813-wrong-tpa3255-48.html#post5600776
i got 2 different boards: v1 and V2
V1
at the old board its the LM2575S with the LM317 an the place for AMS117-3,3 was empty
V2
now its other way round
LM2575T -12 - Set to 12,06 Volt - no LM317 but the AMS117-3,3 is on board
about the fake opamps:
i had a bad opamp and i measure it...cant remember which page,
but to be honest --> change the TL072 its a standard opamp and i guess its still fake...
chris
Sorry for my rude words...
here is the solution:
https://www.diyaudio.com/forums/class-d/309813-wrong-tpa3255-48.html#post5600776
i got 2 different boards: v1 and V2
V1
at the old board its the LM2575S with the LM317 an the place for AMS117-3,3 was empty
V2
now its other way round
LM2575T -12 - Set to 12,06 Volt - no LM317 but the AMS117-3,3 is on board
about the fake opamps:
i had a bad opamp and i measure it...cant remember which page,
but to be honest --> change the TL072 its a standard opamp and i guess its still fake...
chris
Hi Chris,
no problem, and sorry if i overreacted.
thank you, now I understand the opamp thing!
I agree, tl072 is far away from state of the art, but still not that bad (respectable UGBW for audio application, acceptable phase margin, noise and gain, distortion is sligtly better than the one of tpa 3255), in relation to the overall implementation of the board. If it's an actual tl072, of course. Usually i tend to replace a component on a board only if it's gone or if it completely wastes the whole board itself, i am always very afraid to damage the copper tracks. What I wanted to understand was, if that strange measurement result was given by the opamps originally mounted on the board, and i am very releaved to read that it's not the case!
I will still consider to replace the opamps, but as i said, i am a bit afraid to do that, despite my soldering skills are not super bad.
Sergio
no problem, and sorry if i overreacted.
thank you, now I understand the opamp thing!
I agree, tl072 is far away from state of the art, but still not that bad (respectable UGBW for audio application, acceptable phase margin, noise and gain, distortion is sligtly better than the one of tpa 3255), in relation to the overall implementation of the board. If it's an actual tl072, of course. Usually i tend to replace a component on a board only if it's gone or if it completely wastes the whole board itself, i am always very afraid to damage the copper tracks. What I wanted to understand was, if that strange measurement result was given by the opamps originally mounted on the board, and i am very releaved to read that it's not the case!
I will still consider to replace the opamps, but as i said, i am a bit afraid to do that, despite my soldering skills are not super bad.
Sergio
What are some design considerations for adding capacitance to the power supply to the e3 3255 PBTL?
What I've always done is put a soft-start between the bulk caps and the board PSU outputs (Meanwell).
Is bigger better here? Would a 100,000 uF capacitance help/hurt? Would many smaller lower ESR electrolytics bet better for this board?
What I've always done is put a soft-start between the bulk caps and the board PSU outputs (Meanwell).
Is bigger better here? Would a 100,000 uF capacitance help/hurt? Would many smaller lower ESR electrolytics bet better for this board?
Hi linuxfan,
I have a similar problem. So far, my kit looks like the following:raspberry pi with volumio / moode audio + dac audiotrak prodigy cube black edition + sony ta-f es 555 + quadral qlx 155. I know that the set up is rather weak but so far it was enough. The sound was warm, pleasant to listen to and there was no lack of bass. Unfortunately sony ta-f es 555 is heavy and takes up a lot of space and lacks remote control. After reading good reviews of the TPA3255 I decided to build something smaller on it. TPA 3255 from 3eaudio combined with F6 PGA2311 kit from aliexpress. Unfortunately, compared to the sony, the treble is just terribly "hollow". Low tones are rather not lacking. At first I thought it might be some fake NE5532 opamps and wanted to replace them with e.g. LM4562. Then I came across a comment regarding FX-audio tube 01 or 03. Now I've read your comment and would like to ask for help. Is there any inexpensive solution with SE and not balanced?
Thank you in advance and sorry for my english
And it needs to be heavy because it’s well done and it’s unlikely that the TPA 3255 will sound better than that Sony.
Harash, I don't think there's an affordable off-the-shelf tube pre-amp which offers unbalanced input and balanced output. Even a DIY kit from Glassware can be expensive -
Balancer
I suggest to not spend money trying to make the TPA3255 sound nicer. There are other types of class D amplifiers which you should try instead - I'm loving my TPA3221 amplifier right now.
I hear good things about the MA12070, but I can't confirm.
Balancer
I suggest to not spend money trying to make the TPA3255 sound nicer. There are other types of class D amplifiers which you should try instead - I'm loving my TPA3221 amplifier right now.
I hear good things about the MA12070, but I can't confirm.
What is the best way to reduce input voltage to amp ?
1. Increase input resistor before opamp (less wanted case)
2. Reduce R_fb for opamp
3. Add voltage divider before R_in (but will it also change opamp gain stage ?)
Also is it good idea to make PFFB but with higher R_in than 2.7 (set 4.7 for example). Do I need to change other PFFB values from datasheet defaults ?
1. Increase input resistor before opamp (less wanted case)
2. Reduce R_fb for opamp
3. Add voltage divider before R_in (but will it also change opamp gain stage ?)
Also is it good idea to make PFFB but with higher R_in than 2.7 (set 4.7 for example). Do I need to change other PFFB values from datasheet defaults ?
After reading through this thread and many other threads around 'cheaper' chinese boards based on IRS2092 or TPA3255 I really wonder if it is still worth the risk if you are looking for a high power application? The specifications I notice are always a bit fishy, often mentioning the power in 2ohm...or using 10% THD? Further more, prices are not that cheap if you compare it to a 'reputable' board from hypex or icepower.
The icepower 1200AS2 can be had for around 400 euro, it includes the soft start, SMPS, and a powerfull D class amp with a 3 year warranty, lots of documentation and customer support. IF you are a bit adventurous you can buy 7 from the icepower website for around 240 euro each. They are not without faults, some users had issues with these boards, but at least you 'know' what you are buying and it's easy, everything is on 1 board.
A Hypex setup with 2 UCD 400 mono boards and an SMPS 400a400 is also around 400 euro. I can find the TPA3255 with '600w' (into 2 ohm) for 50 euro, (without import tax) but you still need an SMPS, so maybe you can get it all for 300 euro. Not sure if the price difference is worth the 'risk'?
https://www.ebay.com/itm/174490624006?hash=item28a073a006:g:4XQAAOSwCQNfkoWuIf I would buy 4 of these boards I might be in theory able to get 2x1200W into 4 ohm, but I don't believe they will be able to do that, probably closer to 2x600w maximum into 4 ohm...which makes it very close to a hypex UCD400??
I also noticed the most expensive part is the SMPS when you go to higher wattage amplifier, often more expensive than the amplifier boards, and even from China these are not cheap. So is it worth it, or am I missing a more cost effective way? (torrodials need rectifiers, ... making them not that cheap either)
I also noticed that if you want to go to a higher powered TPA3255 or other board, it is often actively cooled.
I need 1000W into 8 ohm or 2Ohm for a subwoofer (so distortion is not that important, neither is high frequency response). It will not need to deliver 1000W constantly so no need to have it cooled actively. I would probably best buy 2 500W boards in 4Ohm so I can make it 1000W into 8 ohm, as finding an amplifier that can deliver 1000W into 2 ohm is extremely difficult. Do you have any recommendations on an alternative setups to a 'ready made' icepower 1200AS2? I would love to look into other options, but so far I did not find a better cost/risk/performance alternative to icepower (or even Hypex, though more expensive) taking the SMPS into account.
Until I see this product:
https://fr.aliexpress.com/item/1005...sceneId":"3482","sku_id":"12000017847920778"}
They are able to put all in 1 box, SMPS, 2x200W amplifier board, DSP, decent case, for 100 euro...so am I missing something, are they keeping the boards more expensive if you buy them separate?
The icepower 1200AS2 can be had for around 400 euro, it includes the soft start, SMPS, and a powerfull D class amp with a 3 year warranty, lots of documentation and customer support. IF you are a bit adventurous you can buy 7 from the icepower website for around 240 euro each. They are not without faults, some users had issues with these boards, but at least you 'know' what you are buying and it's easy, everything is on 1 board.
A Hypex setup with 2 UCD 400 mono boards and an SMPS 400a400 is also around 400 euro. I can find the TPA3255 with '600w' (into 2 ohm) for 50 euro, (without import tax) but you still need an SMPS, so maybe you can get it all for 300 euro. Not sure if the price difference is worth the 'risk'?
https://www.ebay.com/itm/174490624006?hash=item28a073a006:g:4XQAAOSwCQNfkoWuIf I would buy 4 of these boards I might be in theory able to get 2x1200W into 4 ohm, but I don't believe they will be able to do that, probably closer to 2x600w maximum into 4 ohm...which makes it very close to a hypex UCD400??
I also noticed the most expensive part is the SMPS when you go to higher wattage amplifier, often more expensive than the amplifier boards, and even from China these are not cheap. So is it worth it, or am I missing a more cost effective way? (torrodials need rectifiers, ... making them not that cheap either)
I also noticed that if you want to go to a higher powered TPA3255 or other board, it is often actively cooled.
I need 1000W into 8 ohm or 2Ohm for a subwoofer (so distortion is not that important, neither is high frequency response). It will not need to deliver 1000W constantly so no need to have it cooled actively. I would probably best buy 2 500W boards in 4Ohm so I can make it 1000W into 8 ohm, as finding an amplifier that can deliver 1000W into 2 ohm is extremely difficult. Do you have any recommendations on an alternative setups to a 'ready made' icepower 1200AS2? I would love to look into other options, but so far I did not find a better cost/risk/performance alternative to icepower (or even Hypex, though more expensive) taking the SMPS into account.
Until I see this product:
https://fr.aliexpress.com/item/1005...sceneId":"3482","sku_id":"12000017847920778"}
They are able to put all in 1 box, SMPS, 2x200W amplifier board, DSP, decent case, for 100 euro...so am I missing something, are they keeping the boards more expensive if you buy them separate?
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