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Mini Dac TDA1543 X 4 NOS - Page 58

post #856 of 996
thats probably a highly benefitial mod. holco, kiwames are good. if you want to go all out, caddock, vishay film resistors would be it. please let us know if the 'hardness' of the sound disappears with the new resistors.
post #857 of 996

The sound's hardness was reduced considerably for me by re-grounding. More recently I've also ripped out all the TDA1543s in mine and replaced them by a stack of 8 TDA1387s. I used 4+4 in differential mode and an AD830 to subtract one half from the other. Its become the best sounding DAC I've ever built. biggrin.gif Oh and TDA1387s don't get at all hot - 8 of them use about as much juice as a single TDA1543, but they can't accept more than 5.5V hence the need for the active output stage to get CD levels out.

post #858 of 996

I have just change the 680ohm resistor to 360ohm ( 2 180ohm in series) and the sound become smoother, less harsh, soundstage a little more expand but bass is not tight as before :(

post #859 of 996

so i did your resistor mod today, proid. i used 300ohms instead because all i had were 100ohms laying around (3 in series) the sound is indeed softer and more in tune with what my previous 1543 dac sounded like (lite ah) 


i also took out the smoothing cap and put in 2200uf green sanyo in place. this had to be mounted outside the chassis so now i have a big green cap sticking out which kinda looks cute. i also took out the 47(?)uf elna caps that was paralleled to the smoothing cap and instead installed an mkp1870 for bypass. i dunno what this specifically has done to the sound since the resistor mod was performed at the same time but the sound is more dynamic with 'thicker' bass now. not deeper, but just with more body.


also quieter passages are now easier to pick out.

Edited by curiousmuffin - 6/18/12 at 3:39am
post #860 of 996

Hi Guys


Just joined, great place to be. I've read this topic from the beginning and just bought one. Checked it had the proper 3.3v reg, all good.


I would like to replace the tantalum caps by the DAC chips with larger ones before the memory heatsinks I'll fit make it all inaccessible, but can't see from the stock ones which is the correct polarity, they don;t seem to have standard markings on them.


I *think* that the positive leg goes toward the output side of the board, is this right?


Thanks :)

post #861 of 996

No tantalum caps anywhere in mine. Polyester I think are used which have no polarity. If you decide to refit polarized caps then pin 5 of the TDA1543 is the positive one, which is on the output side.

post #862 of 996

Thanks mate. Great posts you've made here, appreciated.


Had no one replied I was going to use non-polarised ones anyway. Maybe I should anyway, I have some spare polyesters kicking around.


I have another question regarding the 47k resistors however. It seems the output impedance of this is set by the 680R resistors, and the LF rolloff of the output cap needs to be calculated based on this. 250R has been recommended but this would mean my poly cap would be way too large (and expensive) so I was going to increase these resistor values to allow a smaller higher quality cap. It will be driving a SS preamp anyway so a low output impedance isn't really that necessary I think?


But what do the 47k resistors do? Can they be bypassed?

post #863 of 996

Since I've subjected my Muse to massive modding I can't go back to it to find out which 47k resistors you're talking about. Are they the ones on the output side of the caps?


The LF roll-off in this case isn't going to be determined by the source impedance, but by the load impedance (seeing as the load impedance is much higher than 680R normally). The 47ks (I think) are there to provide a bias across the caps should the thing you're feeding into have no resistor to gnd. They're probably redundant and if your preamp's impedance is high (like >47k) then you can use a smaller cap by taking them out. Suppose your SS preamp had 100k input resistance, then for -0.1dB @ 20Hz (very conservative) you'd need output caps of 800nF.

post #864 of 996

The 47k resistors sit in between the output caps on the board layout. I'll short them out then.


Glad the rolloff will be a function of the preamp load, that makes things easier and cheaper. :) 

post #865 of 996

Complete DAC/DIY newbie here. I was wondering how easy/complex it would be to fit the Mune DAC that has a single TDA1543 & replace it with a TDA1541? (plug in replacement?). SQ compared to 4x TDA1543?. Higher cost but maybe better?






post #866 of 996
Originally Posted by DavidK35 View Post

Complete DAC/DIY newbie here. I was wondering how easy/complex it would be to fit the Mune DAC that has a single TDA1543 & replace it with a TDA1541? (plug in replacement?). SQ compared to 4x TDA1543?. Higher cost but maybe better?


Very hard indeed to impossible even for an experienced DAC modder like myself. They're totally different chips - one has 8 pins and the other 28. The TDA1541 needs multiple supplies which won't be available in the Muse DAC so you'd need to add fancy regulators. There's no way all that stuff would fit in the Muse case.

post #867 of 996

Ah OK, thank you for the info.

post #868 of 996

Hello, I've this Muse dac and I had read that it is possible to shorten the caps at the output (at the RCA connectors). My question is if my amp Marantz PM7000 will handle with DC offset and not blow my speakers?

post #869 of 996
If this is the inside
and on the far right top are the inputs you can see those red caps. They are probably the input caps (WIMA MKS?).
Here a guy that restored a similar one (PM68): http://marantzforum.nl/forum/index.php?topic=6309.0
I think you'll be ok.
Edited by ]eep - 10/13/12 at 3:56am
post #870 of 996

I've noticed my Muse has an extra 3dB on the left channel. I have a balance pot on my preamp, so can correct for it - but was wondering if it's possible to fix it on the board? Any ideas?

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