Building with the Soekris dam1121

[TNT]

If you put the Mac in working order - why not also try CamillaDSP if you dont have such possibility already? There is a native Mac version and an install script. Very "transparent" EQ.... but, perhaps one thing at a time

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[mcsontos]

Which opamps did you try at the output and which one did you find the most pleasing (if there was a difference at all)?

 

[TNT]

I use the output of the ladders - i.e. bypassed the output stage.

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[mcsontos]

You mean bypassing an external output stage, just taking the output voltages from J1 at Zout=640R? What is the input impedance of your next unit in the chain?

 

[TNT]

Yes 640 ohm. I did one comparison when I got my first DAC and never looked back. A few variations between a couple of k to 50k. According to the designer, the only thing that happens is that the output level is decreased - no other impact. You could short circuit the output without hurting the electronics as I understand it.

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[mcsontos]

I have another question concerning the Atmega-controlled volume: the dam1121 manual says that the COM_RXD, COM_TXD ports work at 3.3V digital level. The Atmega TXD/RXD, on the other hand, operate at 5V level. How do you solve this? Can simply the insertion, say, 2k2 resistors in the RXD/TXD lines save the day? Or do I need to include a proper level shifter?

Thanks,
Miklos

 

[roderickvd]

I recommend a level shifter. A resistor voltage divider might work for slower signals, but might not be very reliable.