Beginner needs help to mod a 4xTDA1543.

Mario_JR · 07:23 PM

Hi!
About two weeks ago I decided to mod a chinese MUSE 4xTDA1543 without knowing anything about TDA1543's

Ive been extensively reading the digital sources section of the forum and found lots of experts in TDA1543, with lots of useful info.
But there is a problem, as I beginner I could not locate in my board where to change/mesure Rload, Rref, BIAS DC and mid point.
The only think I did was to put the TDA's to run at 7,5( gonna raise that soon) and changed the output caps.

Here are some pics of the board =D

face.jpg

back.jpg

I almost forgot, Ive found a NOS of TDA1543 and got 12 of then ( about 80 cents each), decided to pigback 4, but with 8 running in parallel I get lot of noise. What to do to start paralleling then?=D

Thanks

DF96 · 15th March 2011, 12:00 PM

As a general rule it is best to understand something before modding it.

If you want to parallel more chips then you have to change the resistors associated with the Ref pin and output pin. Double the chips, halve the resistances. You also may need to change/adjust the resistors if you change the supply voltage, if it uses passive I/V.

See my website for details.

Mario_JR · 15th March 2011, 10:42 PM

Hi.

Thanks for the help.
Can you explain me what is midpoind?
Mid Point is Bias DC?

Quote:

Originally Posted by DF96

As a general rule it is best to understand something before modding it.

If you want to parallel more chips then you have to change the resistors associated with the Ref pin and output pin. Double the chips, halve the resistances. You also may need to change/adjust the resistors if you change the supply voltage, if it uses passive I/V.

See my website for details.

Mario_JR · 16th March 2011, 01:36 AM

Never mind.. just found it.
YEs! Mid point is DC Bias!

dddac · 19th March 2011, 07:33 AM

Quote:

Originally Posted by DF96

See my website for details.

I did read it, nice work.

just a comment, on the Ri of the dac chip. you calculated it to be 335k.

I actually measured it and it comes at between 30 and 40k, depending on the actual load. The Ri is not completely linear

DF96 · 19th March 2011, 11:35 AM

It was only an estimate, based on simple assumptions and distortion figures claimed by others. I am not surprised that it is wrong!

Mario_JR · 23rd March 2011, 09:29 PM

What is Ri?
Thanks!

Quote:

Originally Posted by dddac

I did read it, nice work.

just a comment, on the Ri of the dac chip. you calculated it to be 335k.

I actually measured it and it comes at between 30 and 40k, depending on the actual load. The Ri is not completely linear

xslavic · 15th February 2012, 02:49 PM

Hi
i also tweaked mine,simple and quite astonished
added in paralel to 10uf some 0.1uF 160v rusian film tubular caps,and made a big improvement also 680ohm resistors repaced with 910r and i have now 17hz bass
i also replaced 2n2 with 1.5n because without them the sound is dull and harsh,and regrounded the RCA output,of course replaced all the other caps and the 0.1 tubular used next to the decoder thing
you can replace the 10uf with 1to 4uF audiophile caps but needs reclaculating resistor values to get the desired filter
thanks,its ok for what its ment for

13th March 2011, 07:09 PM	#1
Mario_JR diyAudio Member Join Date: Jan 2005 Location: Sao Paulo	Beginner needs help to mod a 4xTDA1543. Hi! About two weeks ago I decided to mod a chinese MUSE 4xTDA1543 without knowing anything about TDA1543's Ive been extensively reading the digital sources section of the forum and found lots of experts in TDA1543, with lots of useful info. But there is a problem, as I beginner I could not locate in my board where to change/mesure Rload, Rref, BIAS DC and mid point. The only think I did was to put the TDA's to run at 7,5( gonna raise that soon) and changed the output caps. Here are some pics of the board =D face.jpg back.jpg I almost forgot, Ive found a NOS of TDA1543 and got 12 of then ( about 80 cents each), decided to pigback 4, but with 8 running in parallel I get lot of noise. What to do to start paralleling then?=D Thanks Last edited by Mario_JR; 13th March 2011 at 07:23 PM. Reason: 8XTDA1543

15th February 2012, 02:49 PM	#8
xslavic diyAudio Member Join Date: Feb 2011	I tweaked my tda1543 x4 muse from ebay Hi i also tweaked mine,simple and quite astonished added in paralel to 10uf some 0.1uF 160v rusian film tubular caps,and made a big improvement also 680ohm resistors repaced with 910r and i have now 17hz bass i also replaced 2n2 with 1.5n because without them the sound is dull and harsh,and regrounded the RCA output,of course replaced all the other caps and the 0.1 tubular used next to the decoder thing you can replace the 10uf with 1to 4uF audiophile caps but needs reclaculating resistor values to get the desired filter thanks,its ok for what its ment for

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15th March 2011, 12:00 PM	#2
DF96 diyAudio Member Join Date: May 2007	As a general rule it is best to understand something before modding it. If you want to parallel more chips then you have to change the resistors associated with the Ref pin and output pin. Double the chips, halve the resistances. You also may need to change/adjust the resistors if you change the supply voltage, if it uses passive I/V. See my website for details.

16th March 2011, 01:36 AM	#4
Mario_JR diyAudio Member Join Date: Jan 2005 Location: Sao Paulo	Never mind.. just found it. YEs! Mid point is DC Bias!

19th March 2011, 11:35 AM	#6
DF96 diyAudio Member Join Date: May 2007	It was only an estimate, based on simple assumptions and distortion figures claimed by others. I am not surprised that it is wrong!

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