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jash2008 1st June 2009 05:53 AM

Class D TAS 5261/TPA3122
Finally build a complete amplifier using TAS5261 & TPA3122.

Amp sounds good at low input levels but strongly clips when the input to 3122 is increased.

As I dont have access to an osciloscope, I am unable to find the problem.

can anybody sugget.

I can post the schematic too if any body is intrested.


rajudp 3rd June 2009 03:03 AM

Class D TAS 5261/TPA3122
Please post the design

jash2008 3rd June 2009 04:03 PM

2 Attachment(s)
Here is a 2 page schematic.
Please comment.

Apart from TPA3122, I also tried TPA2000 but same results.

audiomodder 24th June 2009 10:50 PM

2 Attachment(s)
I think he means the design of your specific build.
I am having this exact same problem myself... :(

heres a pic of mine

audiomodder 25th June 2009 07:35 PM

2 Attachment(s)
heres a pic of the underside...
note: i tried a few things to fix the problem already, including adding morewire accross the power lines (to decrease resistance) and tried adding a much more capacitance to the power input in case the problem had something to do with supply pumping. Also tried swaping one of the speaker outputs terminals in case of that too (as mentioned in the datasheet).
really curious what's causing this...maybe it has something to do with the input cap at 1uf? I noticed when the gain setting is on high the input resistance changes and thus the input cap value should differ...but I'm not sure to what and how/if that would cause clipping.

any ideas anyone?
many thanks in advance...

jasonsator1 3rd July 2009 01:38 AM

unbalanced output channel
I have apower amplifier using stk401-130 af ic that has no balance output. itry to balanced with tone control balanced. at frst results,its ok but later on my LSpeaker was burnt out. what is the possible defect? Can I have some tips about this? thank you very much for anybody.....

audiomodder 9th July 2009 04:38 AM

2 Attachment(s)
heres the top side of my build. any help on this? Id really love to finish this project :dead:

theAnonymous1 9th July 2009 07:40 AM


It's really difficult to tell whats going on with your board, the p2p wiring makes it hard to follow what's connected to what.

I can say for sure that supply pumping is not a concern, and a low value input cap will just roll off the low end, not make the amp distort or lower the overall output level.

What's the AC voltage on the output when it starts to distort? Input signal voltage? What's the supply voltage you are using?

There's really only a few things that could be the problem, it's not really a complicated circuit. It's either a problem with the wiring, a component value/type, or the IC is damaged (though not likely).

Sorry, wish I could help out more.

jash2008 13th July 2009 05:22 PM

Hi Audio modder,

Found good solution,

I first converted the analog audio to PCM format then from PCM to PWM

mail me at to have a look at the board design & layout as the picture size is large to post

I used PCM1808 & TAS 5010.

Hope it shall help you. The distortion problem dissapeared although the power output is somewhat lesser.

I shall update you very soon.

jash2008 13th July 2009 05:26 PM


Originally posted by audiomodder
heres the top side of my build. any help on this? Id really love to finish this project :dead:

hi audio modder,

Where are the decoupling / bypass 100nF capacitors in your board.

Have you installed them. This strongly affects the performance of the chip

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