DAC alive

till · 28th April 2004, 06:19 PM

As a result of topics discussed here
TDA1541A/S1 Arrangements

and here

ferrite beads

and here

zener regulator

...

My DAC shows first signs of live

The power supply board and the DAC with reciver works, no I/V stage ubtil now but jumpers set for Vout from AD1865

I feed from the CD670 i got from Jean Paul via SPDIF BNC cable.

till · 28th April 2004, 06:34 PM

and this is 1kHz

till · 28th April 2004, 07:09 PM

No listening music, Vout from AD1865 driving 5m XLR cable to BZLS. The DACs first half is loosely based on http://www.geocities.com/yury_g/dac.htm, next will be D1 stage instead of Vout.

Power supply gives 5V with one 7805 for reciver, one for 74HC04, one for digital supply of DACs, the circuit form the zehner regulator thread above for +-5V DAC analog supply, +-30V for D1 stage with regulators similar to BZLS supply.

When i manage to set the right DAC mode in the CD PRO2 with a microcontroller i will connect the transport direct to the DACs instead of CS8412.

jewilson · 28th April 2004, 07:50 PM

Till,

What kind of power supply noise levels or you seeing on the DAC with the input open and also connected to your transport.

till · 28th April 2004, 07:56 PM

At the DACs analog power supply, or at its signal output?

jewilson · 28th April 2004, 08:07 PM

Till,

On the power supply pins of the DAC. In addition CBS has a test CD that has some low level signals so you can test the lowest order bits for noise. Of course most of that noise will come from the power supply and switching noise on ground when you connect the CD transport with the 8412. Of course you should monitor the DAC output while you look at the power supply noise.
You might want to sync on the master clk or SPDIF to see if your noise is related.

till · 28th April 2004, 08:14 PM

I measure probe directly at -5V supply pin, probe ground 1 cm from AGND pin.

first picture DAC power on, connected to preamp, no connection to SPDIF / BNC open

till · 28th April 2004, 08:16 PM

2nd i connect the CD player with 150cm BNC cable, no playing, adjust the scope for best picture on CRT:

till · 28th April 2004, 08:17 PM

now i play a track silence from CD:

till · 28th April 2004, 08:20 PM

and test track with 1kHz sine wave -0dB

On the picture of the DAC board to see decoupling of the pin measured is 100nF film and 10uF electrolytic.

28th April 2004, 07:50 PM	#4
jewilson diyAudio Member Join Date: May 2002 Location: Plano , TX	Till, What kind of power supply noise levels or you seeing on the DAC with the input open and also connected to your transport. __________________ Jim W.

28th April 2004, 08:07 PM	#6
jewilson diyAudio Member Join Date: May 2002 Location: Plano , TX	Till, On the power supply pins of the DAC. In addition CBS has a test CD that has some low level signals so you can test the lowest order bits for noise. Of course most of that noise will come from the power supply and switching noise on ground when you connect the CD transport with the 8412. Of course you should monitor the DAC output while you look at the power supply noise. You might want to sync on the master clk or SPDIF to see if your noise is related. __________________ Jim W.

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28th April 2004, 07:09 PM	#3
till Banned Join Date: Apr 2002 Location: Germany, Clausthal	No listening music, Vout from AD1865 driving 5m XLR cable to BZLS. The DACs first half is loosely based on http://www.geocities.com/yury_g/dac.htm, next will be D1 stage instead of Vout. Power supply gives 5V with one 7805 for reciver, one for 74HC04, one for digital supply of DACs, the circuit form the zehner regulator thread above for +-5V DAC analog supply, +-30V for D1 stage with regulators similar to BZLS supply. When i manage to set the right DAC mode in the CD PRO2 with a microcontroller i will connect the transport direct to the DACs instead of CS8412.

28th April 2004, 07:56 PM	#5
till Banned Join Date: Apr 2002 Location: Germany, Clausthal	At the DACs analog power supply, or at its signal output?

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