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

[soekris]

@soekris

It is possible to share more information about changes in filters in rev7 and how to implement new. I especially interested is there will be separate blank txt filter file or converter. How to import existing filters, etc.

I own rev3 board and I'm trying to use TNT NOS filter without DC HP because I have to play bit perfect DC samples
Filter brewing for the Soekris R2R

So the problem could be the filter file?

So it's your own file, maybe verifying your setup with a known good filter file....

 

[andrea_mori]

It's not my filter file, it's from TNT.

Anybody know if it work?

Mybe I was not clear several posts ago.

I need to play bit perfect DC samples, so:

- Non oversampling
- no DC high pass

Is there any filter which surely works this way?

 

[TNT]

Mine has OS for sure but no HP filter.

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[andrea_mori]

Is this one?
Filter brewing for the Soekris R2R
Does it work?

What does mean OS with DC sample since the word is always the same?

 

[TNT]

OS: OverSampling
A HP filter blocks DC.

The name indicates: NoDC(filter)...

Anything more?

Why is it that I feel such resistance to help you...

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[andrea_mori]

You have not replied, what does mean OS with DC sample since the word is always the same.
24 bit Hex 40 00 00 means half power, only 23th bit is on.
The wave file contains the same sample 40 00 00 from the beginning to the end.

What does happen to this word with your OS?

 

[andrea_mori]

So it's your own file, maybe verifying your setup with a known good filter file....

Just tried with 1021filt_120.skr downloaded from your website, it does not work, I have the same issue.

 

[andrea_mori]

OS: OverSampling
A HP filter blocks DC.

The name indicates: NoDC(filter)...

Anything more?

Why is it that I feel such resistance to help you...

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So did you write the filter and you don't know what happens to the original signal?

 

[andrea_mori]

So it's your own file, maybe verifying your setup with a known good filter file....

Just for try I have set the baude rate to 9600.

Now it does not work anymore, the uManager starts but all the commands don't work.

Is there a way to reset to 115200?

 

[TNT]

So did you write the filter and you don't know what happens to the original signal?

You don't make any sense. I can not understand what you write.

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[andrea_mori]

You don't make any sense. I can not understand what you write.

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Oh, it seems to me the question is very clear.
However I attach a picture so you can better understand.

As you can see the wave file contains the same word from the beginning to the end: hex 40 00 00, bin 0100 0000 0000 0000 0000 0000.
Is this clear?
Only the 23th bit is on as you can see on the scope.
It's the I2S data, is this clear?

This means DC at the output of the DAC, assuming the DAM1021 raw output is capable of 1.4Vrms when all the bit are on, this means 1.9796 peak Vdc at the DAC output.
Is this clear?

If all the above is clear then the question isc clear.

What is the output of the DAM1021 with the above sample and your filter?
Does it provide constant 1.9796 VDC at raw output if you measure it with a DMM?

 

[TNT]

Did you manage to load the filter?

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[andrea_mori]

No, after I have set the baude rate to 9600 the uManager does not work anymore.
However is there someone who can tell if there is a way to play bit perfect with the Dam1021?

 

[andrea_mori]

Soeren,

is there a way to play bit perfect with the Dam1021?

If so can you pleas tell me what I have I to do?

 

[soekris]

Soeren,

is there a way to play bit perfect with the Dam1021?

If so can you pleas tell me what I have I to do?

The dam1021 is designed to play music, not for your experiments, you're on your own there....

 

[lasercut]

There are multiple filters on the filter file, not all made by TNT, the NOS filter (F7) is the one of interest if you manage to load the file. It should do what you need.

 

[TNT]

Define "bit perfect"?

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[roderickvd]

He writes his intentions in #10351. I don’t know if the pseudo-NOS filters will do as he wants, because obviously the dam is always oversampling in the MHz range but Andrea already knows this. Best he can hope for is that the coefficients are such that after OS the bits are again what they were on the input. gumisb’s latest F5 filter would also be a good candidate to test.

But as long as the custom filters aren’t in, there’s not much point in discussing it further.

 

[roderickvd]

New 1.24 filter files up on website, also new MKROM.EXE. In order to support new rev7 boards there now is a 1.5Mhz x4 FIR2. You can have both FIR2 filters in the file, like on stock file, the correct one will be used by firmware.

Hi Søren, is this also a precursor to a new 1.24 firmware with changed clock tracking as you described earlier?

 

[TNT]

Also for 1121?

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