First DAC project ,TDA1541 current output

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George Kubitsch

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Joined 2002
#1
My first DAC project is the Adagio by Thorsten. I have measured
everything in it: - the dc voltages are working well, - the CS8412
outputs Fsync, SCK, SDATA are as on Data Sheet, - SDATA
is changing together with the music.
I measure with an oscilloscope.
The trouble is: With a (raised for the measuring) 300 ohm I/V resistor I can measure a continous - 2,7 mA current and can not
see any signal on it.
I see only the noise on it generated by the digital ICs, which can be seen on any wire in the circuit
The DAC chip was soldered in, while I debugged the circuit( the TL431 pins were used incorrectly).
Maybe I damaged it ( but what about the - 2,7 mA)?
I need your help, how to go on?
Thanks
George
 
#2
Could be mode madness

If your getting valid lock on receiver - Pin 28 goes low - with signal lock you will see clocks/data etc... and the dac should have 2-3ma and 3-4 volts dc on it's output (it's been a long time since I've actually measured 1541s) that sounds "normal". But if your mode select isn't right you'll get nothing/noise or both, and you will see signal/clks etc on the inputs, but the dac won't pass. I use the following mode 'code' with a 8412 and a TDA1543 (I2S) Pin 24 HIGH and 23, 18, 17 LOW and 16 (select) HIGH. Works for me 🙂
 
#7
George Kubitsch said:
My first DAC project is the Adagio by Thorsten. I have measured
everything in it: - the dc voltages are working well, - the CS8412
outputs Fsync, SCK, SDATA are as on Data Sheet, - SDATA
is changing together with the music.
I measure with an oscilloscope.
The trouble is: With a (raised for the measuring) 300 ohm I/V resistor I can measure a continous - 2,7 mA current and can not
see any signal on it.
I see only the noise on it generated by the digital ICs, which can be seen on any wire in the circuit
The DAC chip was soldered in, while I debugged the circuit( the TL431 pins were used incorrectly).
Maybe I damaged it ( but what about the - 2,7 mA)?
I need your help, how to go on?
Thanks
George
Click to expand...

Hello,
i am today by first step to DAC ( collect informatoon and parts ), what you are just madea and finished.
Please send me your comment , how you like the results of this DAC. Whay you aren't made a DAC with the newest ships--BB1704 etc....
hifiwolf
 
#8
More help needed

Hi Hifiwolf!
I am a beginner in the DAC world, so I wanted to choose a project, which was realized with good result.
So I choosed the "ADAGIO" DAC made by Thorsten Loesch.
It is simple, no oversampling, no digital filtering, and has
a tube output.
You can see and read about it :
http://www.fortunecity.com/rivendell/xentar/1179/projects/adagio/Adagio.html
The schematic has some mistakes, and the TDA1541 is a rare bird,
but this road is used by others too , with success:
http://www.soundstage.com/revequip/zanden_5000.htm
I have just finished it with the help of the kind great guys here.
I connected it to my balanced OTL amplifier without preamp:
The bass and treble extended, more dinamic , the music is more
involving. So the DAC is promising, but one problem remained.
There is some hum and buzz, which is generated by the the tube
output of the DAC , and I could not solve it yet.
To make a try I connected the DAC to my balanced preamp from just the seconder winding of the transformer (without the passive filter and without the tube output ) and it sounded equally good as before, but more output voltage and so the tube output stage is needed.
More impressions later.

Scottnixon, Elso, ....!
I have run out of thoughts to solve the above mentioned hum-
buzz of the tube output stage. Any proposal?
Or I have to modify to a new balanced symmetrical tube output with better CMNR?
Thanks in advance
George
 
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