Parallel TDA1541A non-o/s DAC Kits

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#41
Thank you for your help, It's almost clear now 🙂


If I have the time tomorrow, I'll try to draw a schematic of what I understood. An image tells more than a thousand words 😉 I think it will be easier for you to tell me if I'm right or wrong, and to see where I'm wrong.

Alex
 
#44
Kuei Yang Wang said:
Konnichiwa,

The DAC has a digital +5V Supply and +/- supply for the "analogue" section. Hence it has two "PSU common" (aka -V in case of positive supplies) pins, which should be used to form independent supply current loops. I really cannot explain it any better, sorry.

I have/had somewhere an expanded set of details, but the -15V and the +6V (in most Philips applications this is 6V not 5V) are the analogue section and there is a corresponding PSU pin, the other PSU Pin and Ground are logic.

...
Click to expand...

To my information -15 is analog and +5 and -5 are digital supplies.
Could be wrong, only read this on the net at some locations.
:xeye:

Greetings,
 
#45
Konnichiwa,

guido said:
To my information -15 is analog and +5 and -5 are digital supplies.
Could be wrong, only read this on the net at some locations.
:xeye:
Click to expand...

To be sure I'd need to look up a lot of stuff that's in tha attic and it will take time which I don't have. So someone else please check.

Sayonara
 
#48
parallel

Hi Kuei Yang Wang,

this is the topscreenof the PCB. CS8414/8412 with parallel TDA1541a only.

any comment to correct??

thanks

thomas

www.diyaudiocraft.com
 

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#50
Which supply pins are analog?

:smash:

Refering back to the question over which supply pins are digital and which are analog...

I personally think that the -15V and -5V (or 6V in most Philips applications) are analog and the +5V is digital. This is based on the fact that the DEM reclocking circuit is referenced to the -5/6V pin (see DEM reclocking circuit posted on this forum). We all know that oscillators such as the DEM oscillator are analog so I think that the -5/6V supply is analog.

At least that is what I think...now I will have to redo my DAC grounding, and try -6V instead of -5V to see if there is any difference in sound quality.

:hot:
 
#52
Re: Which supply pins are analog?

Zodiac said:
:smash:

Refering back to the question over which supply pins are digital and which are analog...

I personally think that the -15V and -5V (or 6V in most Philips applications) are analog and the +5V is digital. This is based on the fact that the DEM reclocking circuit is referenced to the -5/6V pin (see DEM reclocking circuit posted on this forum). We all know that oscillators such as the DEM oscillator are analog so I think that the -5/6V supply is analog.

At least that is what I think...now I will have to redo my DAC grounding, and try -6V instead of -5V to see if there is any difference in sound quality.

:hot:
Click to expand...

Maybe, maybe not 😕

Maybe he just needed -6 and used the ps available. I am going to ask him, we have an email conversation ongoing about his DEM circuit (more about the why on reclocking WS).

Greetings,

Guido

PS The conclusion on WS is that it is not beneficial in i2s mode....
 
#53
Put some details up

Guido,

Would be interesting if you put the key points of your exchanges with Henk up in the DEM thread. I did the DEM reclocking, worked a treat, and my TDA1541 is in I2S mode....

p.s. 4Fs sounds much better than 8Fs for the DEM circuit

I agree though about the -6V. Ask him!

:smash: :hot: :smash:
 
#54
Re: Put some details up

Zodiac said:
Guido,

Would be interesting if you put the key points of your exchanges with Henk up in the DEM thread. I did the DEM reclocking, worked a treat, and my TDA1541 is in I2S mode....

p.s. 4Fs sounds much better than 8Fs for the DEM circuit

I agree though about the -6V. Ask him!

:smash: :hot: :smash:
Click to expand...

I'll ask about that too, maybe my comment on WS is already 'out of line'... 4Fs probably sounds better because of the speed the circuit can handle. Depends what your Fs is... (os or non-os).

Reclocking of WS has nothing to do with the DEM modification :att'n:

Gr,
 
#56
Re: Put some details up

Zodiac said:
Guido,

Would be interesting if you put the key points of your exchanges with Henk up in the DEM thread. I did the DEM reclocking, worked a treat, and my TDA1541 is in I2S mode....

p.s. 4Fs sounds much better than 8Fs for the DEM circuit

I agree though about the -6V. Ask him!

:smash: :hot: :smash:
Click to expand...


Zodiac,
Thanks for comparing the two DEM frequencies.

Henk used -6V because that's just what's typically available in Philips cd players. I have -6.25Vdc for this supply.
-5V should work just fine...
😎
 
#57
It is quick to compare

Rudolf,

I'm not quite sure how you set up your DEM board but comparing the two frequencies is easy - just move one connection on the frequency divider chip. I used 74HC163s for this purpose....

One thing that made me try the 4Fs instead of 8Fs is that if you look at the TDA1541 (not A) data sheet (with the onboard DEM capacitor) it states that 200kHz is normal DEM oscillator frequency. 4fs is 176.4kHz and 8Fs is 352.8KHz, thus it also makes some sense from an engineering perspective :hot:

Guido,

Just for reference, my TDA1541 implementation is non-o/s. I came across an interesting article on the web which may go some way to explaining why reclocking all three lines makes an audible difference.

http://www.stereophile.com/interviews/850/index1.html

It refers to the fact that the TDA1541 doesn't like to see noise at its input pins. Makes sense....:hot:

One day I might actually stop fiddling around with my TDA dac and actually play some music on it!!

:smash:
 
#58
Re: It is quick to compare

I know it's easy to compare Zodiac, I just never bothered.
I already knew the internal TDA1541 logic wouldn't be fast enough at higher frequencies.
Seems we had the same reasoning based on the 200kHz 🙂
 
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