Tda1541 decoupling caps

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Hi all.

I have searched and read a lot of info on the subject.

Problem is that my pcb not has a lot of space and the pitch is 5 mm.
So, my local store have these caps that will fit.
Anyone can comment if some are better then others?

POLY MMK 100nf/63v
Wima MKS 2 100nf-220nf/63v
Philips MKT370 100nf/100v

I did read that many think MKP is better, but i dont have the space for those.

Regards //Daniel
 
Actually, the Polyester FILTER caps are the best ones for this use - these are those Wima MKS ones and if you can increase the size up to 1uF and any voltage above 9 volts (the voltage across the pins) that's about as good as you'll get - I use the Siemens/Epcos B32529 1uF/63 volt ones that are quite similar and should also be available from ELFA.

You can easily solder the caps, or some of them, underneath the pcb - there are a few of the SMD versions of the same type of caps that can also be easily soldered directly onto the pins underneath the pcb that'll fit that 5mm criteria
 
14 DEM caps: If you store have it for the MKS2 : chose 2.5 mm pitch legs (despite the 5 mm pitch of the board).

dem sync cap : idem or silver mica !

-15V; +/-5V Voltage rails... : joker ! If no BG or discontinued OSCON SP : try :

-polymer : UCC : PSA serie
-polymer : Panasonic SEP (not SEPC/F)

For the 5V rails : an alternative is the Nichicon Polymer SE serie (PSE) : max is 6.3V in this serie !
 
What sort of regs is working for the supply rails of the TDA chip ? With those value I believe it's simple 78/79 xx regs ? So keep the tantalum and the 220 uf FG on the pcb (and even better if you have old caps like Nichicon SE or VX (SE serie better here at this place though to be lower in the old Nichicon line than the VX) you keep on old broken cd players Philips, etc !
These caps are usefull to get low the output impedance of those serie regs !
But if the regs are also a little far from the dac chip (and better splitted by a chocke or a resistor: keep in mind the ref I gave above to putt its the nearest you can to the dac PS rails : try the one you prefer by test & error with ears ! Those caps are cheap, and yes spend a little extra for the 14 dem caps with Wima MKS2 2.5 mm pitch instead 5 mm; try 0.220 uF instead 0.1 uF. swap the dem sync cap (around 470 pico most of the time) by the same Wima ref but keeping the same value; or put a silver mica if having one)
Here Farnell have a new offer with no minimal amount, certainly the sme in Sweden !
 
Hello Esgigt, what new ?

if this is the one used here : I stay on my advices ! chockes are a good news between the dac chips and the output reg caps ! If me I would swap the 10 uf and 0.1 uF caps of each local decoupling PS rails around the dac by the ones I listed though some would say, caps are not important blah blah blah... they are and can waste a dac if badly choosed according to my modest experience.

There are also some other tips to improve LM3x regs... a lot of advices here on Diya !

If Daniel has some Black Gate, better ! or Discontinued OSCON SP ?
The list I given is good according to my test and give different sound result staying good for each of them !

cheers
 
Hello.

Yes, you are right about the regs. I'm using 317/337 regs with a choke (100uH) at output. And the caps ofcourse. And the TL431 close the the dac.
I have some old (around 1991) BG caps desolder from a cd player. Can i use then insteed of the UFG caps? But maybe thet are old and dry...
I order 2.5 pitch Wima MKS2 100nf from UK seller on eBay. I will use them.

Best Regards //Daniel
 
Sorry I forgott this TL431, I believed you have the Analog Metric due to the pdf given by Esgigt (@Esgigt : why this pdf, I didn't understand ?!)

Daniel, is ist an Analog Metric you modyfied ?

So forgett what I said : between the tl431 (and its transistor ???) and the dac chip, the decoupling cap has to have a low ESR (not like the tantalum).

Listen your player, remove the tantalum cap and listen to again : it should be less dry ! Capicitance value here is not so important (everything is fine between 0.2 uF and the values you use with a near result). I will try the Wima again, again 2.5 mm pitch (between 0.220 uF to 1 uF) and not the 5 mm pitch. But the black Gate will be the best, firstly with the - 15V, but also with the 5V rails ! Try listen again ! You must keep what you prefer.
You can keep also the polymer I talk about though the capacitance value is too high but will not make the things worst ! (Here this is the TL431 which allow a very low impedance :) )

The caps before who feed the TL431 are important : here low esr needed and greater capacitance than at the output which is a simple local decoupling cap : you should have the shematic to understand which cap feed the shunt reg ! The output cap of the serie reg ? A cap before the tl431 but after the schocks ?...!

Beginn with the BG just at the feets of the DAC (instead the FG and the tantalum ! but firstly you should try to remove the tantalum).

When tweaking a device : one part swap at once... if you change more than 2 parts, you don't know what you do :) ! Good game, I like it, makes me thing about the Lego when I was Young :happy2: !
 
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Hi!

I have built a Analoge Metric pcb before. Now i'm about to "start over" with my own pcb. It will arive next week. First time i will use SMD parts..we will see about that :)

Anyway, i did one error on the PCB. With the TL431 to -5V. I don't know how importen the -5v is? i can of course cut 2 traces and take some wire to correct this.

Thanks for the info about tant.caps after TL431. I will take some other el.lyt caps.

Best regards // Daniel
 
Hello Esgigt, what new ?
not much, I guess, my dear friend ;)
if this is the one used here : I stay on my advices ! chockes are a good news between the dac chips and the output reg caps ! If me I would swap the 10 uf and 0.1 uF caps of each local decoupling PS rails around the dac by the ones I listed
If it works, why not...
though some would say, caps are not important blah blah blah...
... and they are right... caps are not important, they are crucial...:D
they are and can waste a dac if badly choosen according to my modest experience.

There are also some other tips to improve LM3x regs... a lot of advices here on Diya !

If Daniel has some Black Gate, better ! or Discontinued OSCON SP ?
The list I given is good according to my test and give different sound result staying good for each of them !

cheers
Also noticed that EC confirms that the ripple/noise rejection on the TDA's +5V and -5V rails is one of the most crucial aspects to ensure good SQ?
And yes.. if BG's are available, be sure to use them in that spot (with proper chokes).

Along with proper DEM frequency selection of course..
 
@Esgigt : why this pdf, I didn't understand ?!)
It was to emphasize the importance of some aspects of TDA1541 design.

Proper clock architecture and proper PS design. They are make- or break factors.. besides proper grounding.

From the document you can learn that the decoupling caps also belong to the PS domain of the TDA1541.. and therefore are crucial as well.
 
Ok, understand !

I believe Daniel should post him shematic on the "any good TDA1541 kit ?" : both to re read it and also to show and benchmark him layout to have multiple advices around diferent points. Also pictures help as well.

Good experience than to draw a pcb ! I'm confused I have to finish a PS to test the dac board than a country fellow of Daniel made around two AD1862... have all, true old dac chips bought at Rochester, a lot of PS from Mravica member, 2 kilos of traffos, Rhopoint resistors, BG, OSCON SP.... buuuuuuut 2 symetric analog shunt regs ! The verroboard are boring to me, and I should myself do the effort to use those drawing plateforms to make my pcbs...

Ah l'Audio !:D
 
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