Filter brewing for the Soekris R2R

[soekris]

Hmm, not much usefull feedback.... So I did the dac1421 & dac1541 firmware with the new larger 4K filters, they're now up at:

dac1421: http://www.soekris.dk/download/dac1421/1421_full_120.skr
dac1541: http://www.soekris.dk/download/dac1541/1541_full_120.skr

Just go into uManager as usual, do "download" followed by "update".

The dam1021 and dam1121 will follow just after the easter vacation, they take a little more time as those are older than the current dac1421/dac1541 firmware.

 

[SebastianL]

Nice Søren. Looking forward to the dam 1021 firmware update!

 

[Dimdim]

Very nice! I know that I'll definitely appreciate the new firmware.

 

[bambadoo]

Thanks alot. Waiting for the dam1021 firmware.
Are there anything else implemented/new/changed beside larger filters?

 

[danny_66]

Hi Soekris,
Which 4k filters did you include in the update?
Regards,
Danny

 

[jacklee]

Hi Søren,

Could you please also add the onboard clock-bypass feature to the new firmware for the DAM1021/1121? Thanks!

 

[jpak]

Would anyone happen to have the link to the filter-less "filter"? I am planning to try the upsampling of redbook via HQPlayer.

 

[Dimdim]

You don't need a special filter to do that. Just upsample to 352/384 and the first filter will be bypassed anyway.

 

[jpak]

You don't need a special filter to do that. Just upsample to 352/384 and the first filter will be bypassed anyway.

Dam (pun intended) that is good news! Not doubting you Dimdim, @soekris would you be able to verify that with the latest version of the dam1021 (mine is from a couple of months ago)?

 

[TNT]

That has been there from the beginning.

//

 

[bambadoo]

Soren, have you tried the different Albretch windows in rephase?

I have and I truly liked it

 

[bambadoo]

The dam1021 and dam1121 will follow just after the easter vacation, they take a little more time as those are older than the current dac1421/dac1541 firmware.

Any news here ?

 

[PET240]

Question,

Have only just ordered my board, bit slow on the uptake, have been looking about, is there a way to just play music with the original sample rate and not use the upsampling in the DAC FPGA?

From what I have read the "NOS" filter still uses the upsampling side.

Whats are the options here please? Have tried searching but haven't found a search term that answers my question yet.

Thanks in advance,

Drew.

 

[Dimdim]

Short answer is "no". You need to let the FPGA do its job in order to drive the R-2R ladder. That constitutes upsampling.

The "NOS" filters bypass the "first stage" of upsampling, but there is no way to bypass the "final stage".

 

[PET240]

OK, didn't realise there was 2 rounds of upsampling!

Thanks Dimdim!

Have you tried the "NOS" filter? Personal favourite? Upsampling in the DAC preferrred or use external method and just feed 352/384?

Thanks,

Drew.

 

[oneoclock]

Short answer is "no". You need to let the FPGA do its job in order to drive the R-2R ladder. That constitutes upsampling.

The "NOS" filters bypass the "first stage" of upsampling, but there is no way to bypass the "final stage".

There are sets of filters like the one I have configured, or the one of Bambado, that have the F7 NOS filter in both the FIR1 and the FIR2 filters. Then, selecting F7, behaves like an authentic DAC NOS without oversampling. The "final stage" second oversampling behaves in that case just as the first oversampling, it take F11 NOS filter, does not perform oversampling. And it can be verified with an oscilloscope.

 

[PET240]

Hey oneoclock,

That excites me!

I take it if I search this thread for you and bambado I would find a link to download or have you not shared them as yet?

If you haven't, may I please grab whichever one or both please?

Thanks muchly,

Drew

 

[oneoclock]

http://www.diyaudio.com/forums/digi...ilter-brewing-soekris-r2r-28.html#post5113505

 

[kronzilla]

I ordered a couple weeks ago my dam1021 but wich firmware has the board? Ik hope the last one.....? I want the best sound only from cd with i2s so no hocus pocus giga mega upsampling or so.... Just the best sound from this dac....

 

[TNT]

Yr – Vaervarsel for Fyn, Syddanmark (Danmark)