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"Reference" TDA1541A DAC with I2S-BUS architecture

Surface Finish for future PCB´s

  • ENIG - Electroless Nickle/Immersion Gold

    Votes: 93 48.7%

  • Immersion Silver

    Votes: 54 28.3%

  • Immersion Tin

    Votes: 24 12.6%

  • OSP - Organic Solderability Preservatives

    Votes: 20 10.5%
  • Total voters
    191
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S

studiostevus

Member
Joined 2009
Transformer problem solved... turned out my DMM was malfunctioning! What are the odds of that??

I actually got some sort of output now from the TDA using a 75ohm resistor to gnd yesterday, but it was horribly distorted. A sine wave from a test CD looked like a square signal, but something was moving.

I just tried again, and let it play for some minutes and after a while .......... a NICE CLEAN SIGNAL APPEARED !!!! :D:D

Victory at last! This weekend I will rig up an output stage, and then I will finally get this baby going!

Needless to say, I am pretty pleased with this!
 
S

studiostevus

Member
Joined 2009
And while I am at it, I want to take this opportunity to thank Oliver for the Sunday morning session 2 weeks ago at his place. He mentioned it was his honour driving him, and he spent considerable time getting my dac boards going! So thanks to Oliver!! :)

It turned out that the problem in my boards were the small inductors on the board. These had (maybe through soldering, maybe through transport) stopped functioning. So this is one to check first if your board doesnt work, and avoid some sleepness nights :yawn:
 
N

noizas

Member
Joined 2009
Hi Studiostevus

it is nice to hear you have solved you issues succesfully :):)

studiostevus said:
Transformer problem solved... turned out my DMM was malfunctioning! What are the odds of that??
Click to expand...

Because I still have my shunt regulator unsolved, it is interesting to know how you solved the transformer problem? Does high voltage input really influence on too high output or here was something else?

studiostevus said:
I just tried again, and let it play for some minutes and after a while .......... a NICE CLEAN SIGNAL APPEARED !!!! :D:D
Click to expand...

Now you will be happier and happier every day next week at least :D - I have experience that TDA1541 is going to "burn in". So be patient please...;)
For example my double crown was going onto it's real sound more than one month! I was playing mine Philips CD 960 at least few hours per day.

studiostevus said:
Victory at last! This weekend I will rig up an output stage, and then I will finally get this baby going!
Click to expand...

Best wishes for your weekend!
Will wait for review on your DAC.
 
S

studiostevus

Member
Joined 2009
noizas said:
Hi Studiostevus

it is nice to hear you have solved you issues succesfully :):)



Because I still have my shunt regulator unsolved, it is interesting to know how you solved the transformer problem? Does high voltage input really influence on too high output or here was something else?



Now you will be happier and happier every day next week at least :D - I have experience that TDA1541 is going to "burn in". So be patient please...;)
For example my double crown was going onto it's real sound more than one month! I was playing mine Philips CD 960 at least few hours per day.



Best wishes for your weekend!
Will wait for review on your DAC.
Click to expand...

There was actually nothing wrong with the transformer. Just my DMM was very consistent in displaying 46% more voltage than it actually measured. Hence, I thought it was 17V while it was a nice 12V. For the same reason I turned down the shunts until the DMM read 6V and I couldnt get lower than that. In reality they were giving only 4V...

So with a new DMM I could turn up the shunts, fiddle around a bit more, and voila!
 
C

crobbins5421

Member
Joined 2007
Impressions on the DAC board mod...

The bypass mod on the DAC board is complete and I agree with the other posts that it made a positive difference in my system.

While the detail improved, the biggest change for me was the soundstage clarity (defined spaces for instruments and voices) and "analog smoothness". Unbelieveably good......
 
N

noizas

Member
Joined 2009
studiostevus said:
Guys, good news.

We have lift-off!! I now also got my Pedja Rogic i/v stage going, and I finally (after 9 months) have music out of this thing.

... now happily burning in ...
Click to expand...

Excellent :):):)

I have good news too - have fixed my [-15V] Salas shunt regulator (here was impossible to make regulation of output voltage).

As Oliver and me suspected - one 2SK170 was damaged.
However not the next to BC560, but one is "in charge" as CCS of reference voltage [two LEDs]) - you can see in attached picture which.

This damaged FET now is replaced and everything seems to be ok.
 

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R

robots

Member
Joined 2010
dvb-projekt said:
Is attached in my Blog.

:wave:
Click to expand...

Thanks for uploading that Oliver.

The BCK output from my Twisted Pear i2s converter is shown in the attached picture. Is it supposed to look that bad? Also it seems to have a fair bit of jitter. Also it is at about 3.07 Mhz instead of 2.82.

This trace is from the converter removed from the circuit and powered by 3 AA batteries, optical source. It looks the same while in the circuit.

:drink:
 

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R

robots

Member
Joined 2010
took some more screen shots, one with a persist trace showing BCK jitter and the second shows the frequency spectrum, which is quite messy. Lots of high order harmonics. Also the BCK frequency is 3.07 MHz.

So i think there is something wrong with my TP SPDIF board?
 

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N

noizas

Member
Joined 2009
robots said:
took some more screen shots, one with a persist trace showing BCK jitter and the second shows the frequency spectrum, which is quite messy. Lots of high order harmonics. Also the BCK frequency is 3.07 MHz.

So i think there is something wrong with my TP SPDIF board?
Click to expand...

I don't think your SPDIF/I2S converter is damaged. 3,07 Mhz means only that it is running on 48kHz sample rate, not 44.1 kHz as from CD source.

Concerning long slopes in the trace of BCK -IMHO the point is that your osciloscope PCSGU250 has too narrow bandwith - for clear shot of 3.07 Mhz BCK you need bandwith about 50 - 60 Mhz, not 12 Mhz as you have.

And sampling rate also can be too low - even with 25MHz sampling you will "catch" about 8 samples per 3.07Mhz period. So 4 samples per half period only... really bad :rolleyes:

There are some data of your oscilloscope:
◦bandwidth: two channels DC to 12 MHz ±3dB
◦time base: 0.1µs to 500ms per division
◦sampling frequency: 250Hz to 25MHz
 
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