What is wrong with TPA3255?

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#903
Thank you, chermann,

I just switched to all Silmic II 10uF 35v for every cap and it sounds very nice. Listening to it on my reference speakers at present. No lack of highs or clarity.

784407d1569711062-tpa3255-reference-design-class-amp-gb-tpa3255-rev0b-silmic-caps-02-jpg
 

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#909
Hi

for me its logical to de coupling mechanically. a sub has a linear movement about 5-10mm a twetter much less -lets say 1mm max.
so every mechanical stress (vibrations) that comes from the sub driver interact with the twetter and with the stand wherer the speaker is mechanical coupled. the target is th let the mecahnicel swing(vibrations) let go away to a defined region - not to the chassis

if you think about a the mechanical decoupling in very good turntables then you understand me.

chris
 
#911
wealas said:
What I've done is to keep the amp muted all the time and only unmute via a raspberry pi GPIO when it starts playing music. If the power goes out the raspi goes out fast and the mute kicks in before the SMPS power ramps down and causes the pop.
Obviously, a dedicated controller that would watch the fault signal and trigger the reset would be better but that would be another project.
Click to expand...

Can you (or anyone - it was a while ago!) point me to a schematic/piece of code for this?
 
#915
fake amp modifications

Hi


my TPA3255 - Fake amp" post 767.
https://www.diyaudio.com/forums/class-d/309813-wrong-tpa3255-77.html#post5701127
....was running about 5 month by my brothers big house. at this hot summer he was happy that he don´t fire up his F5 class A clone.😀
at some compare sessions i can say that my TPA3255 sound nice but the voices and vocals are not "stable", the board has the AD8599 and i claimed that this configuration is not so good as the AD1602 opamp. additionally the background noise was not as good as i remember - long term listening gets little bit boring. i thought the amp was better before i deliver this to my brother..😉😀



source:

i played around with the TPA3116 dual amp and in this thread i get the hint to use a 470nF + 10 R Zobel
https://www.diyaudio.com/forums/cla...pa3116-2-0-100w-dual-chip-12.html#post5876827
this push be to try it out on my TPA3255 - fake amp.


the zobel is like a big LPF for the complete amp.

i tried 220nF +10R (3W), 2x 220nF +10R (3W), 680n+10R (3W) at the speaker terminals.

immediately i realized that the 220nF+10R - small Zobel helps very much!


finally i found the 2x 220nF +10R as best solution. now its dead quiet and the amps sounds very realistic🙂. the dynamic is very very nice.
680nF is too much - the 220NF is good but the annoying "ringing" is still here.


at the attached document you will find some measurements without filter (right) and the 3 different zobel networks.


the pics shows a contest where some DIY speaker (4" +1, partly active) guys made a session. at this event i moved my DAC (CM6631A + fake amp) with me. i know that they are not really interested in compare "electronics". so i enjoy and wait...late evening i was lucky to demonstrate my DAC+amp....😀
the small speakers on the table - "twiggy" (81db...) i have to push over 1 hour with a lot of titles... i get from all guys very positive feedback😎



chris
 

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#916
For all who have a differential dac and don't care about bleeding ear sound levels I ecourage you to just bypass
the whole input Stage. It's a worthwhile sonic improvement. There are four 100ohm resistors next to the opamps
where you can attache your leads.

Greets,
Klaus
 
#917
Hello, mates.Got my China's tpa3255 board with samwha cspacitors instead of Elna as it was promised. Sounds good. Much better than complete unit YJ i had before with Bluetooth onboard. This board delivering extra bass as i expected with my psu 48V/1200 w. It was only once i did it turnoff due protection circuit with very high volume on B&W 603. This board paired with b&w603 really make audible sence of biwiring. Even regular copper audiocable 2,5 sq.mm immediately extend highs being connected biwiring. Mistics in cables exists imho. Btw on one photo i used direct plugin DAC ES9082 to tpa3255 directly eliminating any cables. I tried to find rca connectors male- male rca but they are not available nearby, ordered via Ali express of course they anything even what seems stupid.
 

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#918
Hi all

I am really sorry I did't read at all this topic, but could you please tell me or to sum up: buying tpa3255 board from Aliexpress is it a good idea? Whats wrong with them? Or in general it is good?

If not, recommend me please where to buy.
Thanks
 
#920
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