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Reference DAC Module - Discrete R-2R Sign Magnitude 24 bit 384 KHz

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#6,362
Hello guys!

I a writing for something that might have been said elsewhere. I tried byt did not find anything relevant I would be pleased if I had a brief reply.

I installed the latest filters, among which there exists the classic NOS filter. I have observed on the oscilloscope that the 10kHz and 20kHz sine waves (for 16/44.1 signal) do not appear to relate to classic NOS response. Judging from what I see on 16/44.1 signal, this module oversamples at least 4 times.

Is this true?

Is there a way to eliminate completely any oversampling process?

Thank you.
Peter
 
#6,365
petavgeris said:
Hello guys!

I a writing for something that might have been said elsewhere. I tried byt did not find anything relevant I would be pleased if I had a brief reply.

I installed the latest filters, among which there exists the classic NOS filter. I have observed on the oscilloscope that the 10kHz and 20kHz sine waves (for 16/44.1 signal) do not appear to relate to classic NOS response. Judging from what I see on 16/44.1 signal, this module oversamples at least 4 times.

Is this true?

Is there a way to eliminate completely any oversampling process?

Thank you.
Peter
Click to expand...

If there were a Soekris DAM F.A.Q., this question would be damn near the top of it: http://www.diyaudio.com/forums/vend...magnitude-24-bit-384-khz-515.html#post4674073
 
#6,366
DC Supply to DAM1021

Hi All,

My apology if this has been asked/answered elsewhere but I don't seen to be able to locate a definite answer so here goes:

Just got a DAM1021 board and is trying figure out the power supply to the board. This will be installed in an existing DAC so the only option available is +10VDC and -10VDC, i.e., AC not available. I planned to use two DEXA regulators to supply the DC.

Now according to the official doc the original AC inputs were passed through two diode bridges to provide the + & - DC outputs. However if the input supply GND (J1) also passes through diode as indicated by the doc then it will have a small potential difference (due to diode voltage drop) compared to the output GND. This normally won't be a problem if the source is AC but in my case the source is DC and the input GND is shared with the rest of the DAC which means when I connect the board's other GND connections (e.g., audio output) it will tie the board's GND to the input GND. This could result in a loop where current will flow because of the potential difference.

I tried measuring the input GND (J1) and the board's GND (screw hole) and it seems they are directly connected, i.e., not through a diode, so I am a bit confused here. And there appears to be only a single diode bridge (D2) near the supply input? How is the negative rail generated?

Wonder if anyone can shed some light on this? I try not to fry the board the first time powering it ...

Thanks!
 
#6,367
jacklee said:
Hi All,

My apology if this has been asked/answered elsewhere but I don't seen to be able to locate a definite answer so here goes:

Just got a DAM1021 board and is trying figure out the power supply to the board. This will be installed in an existing DAC so the only option available is +10VDC and -10VDC, i.e., AC not available. I planned to use two DEXA regulators to supply the DC.

Now according to the official doc the original AC inputs were passed through two diode bridges to provide the + & - DC outputs. However if the input supply GND (J1) also passes through diode as indicated by the doc then it will have a small potential difference (due to diode voltage drop) compared to the output GND. This normally won't be a problem if the source is AC but in my case the source is DC and the input GND is shared with the rest of the DAC which means when I connect the board's other GND connections (e.g., audio output) it will tie the board's GND to the input GND. This could result in a loop where current will flow because of the potential difference.

I tried measuring the input GND (J1) and the board's GND (screw hole) and it seems they are directly connected, i.e., not through a diode, so I am a bit confused here. And there appears to be only a single diode bridge (D2) near the supply input? How is the negative rail generated?

Wonder if anyone can shed some light on this? I try not to fry the board the first time powering it ...

Thanks!
Click to expand...

That drawing is incorrect, there is only one diode bridge and you can just connect the +-10V as normal.
 
#6,372
Update

Update，setup kits test OK.This is the third edition, the fourth edition will be the official version. The official version will use thick copper and gold-plated circuit boards. dam1021setup-v1.jpg
 
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