Is there a better filter then DF1704

[sumotan]

Hi Guys,

Have a Sonic Frontier SFD 2 dac board which am finally going to resurrect.
The input receiver is dead. Original idea was to run I2S to bypass the input
receiver all together. Currently the filter is a NPC 5803 apt. I'm aware that
a German company that sells an adapter board for this conversion with the DF1704. From data it seems that the DF 1704 is able to receive I2S signals
right, so this would solve one of the headaches. The other is since I'm going through so much hassle to resurrect the dac , are there better digital filters out there ? Thanks in advance guys. I know it's an oldie but it's a good one which is
such a waste if I just leave it aside

[stephensank]

In my rather extensive a/b listening testing on this subject, the NPC SM5847 is just as good, but not better. Haven't heard a better DF yet than either, although I have not tested against the DF1706, but I seriously doubt there's any audible difference to be had there.

[abraxalito]

A better digital filter is none, IME. Does the SFD-2 have UltraAnalog DAC modules?

[sumotan]

Thanks Stephen.

[sumotan]

Yes Abraxalito, 2 Ultra Analog dac in balance mode

[elektroj]

Jaffrie,
Sound-wise SM5803 is only so-so. DF1704, in contrast, is fine filter, but it won't work with UltraAnalog modules without some additional glue logic. UA DACs need filters that have 'De-glitch' output.
Three candidates that come to mind are SM5842, SM5847 and PMD100.
(I know the DF1704 quite well, I've fitted it to many different CD players/DACs over the last 10+ years. In fact, everything that the German 'company' you've mentioned was/is selling was designed/manufactured by me. All the later versions by him are reverse engineered knock-offs of mine, so I can't say whether they will work as expected or not..)

[hollowman]

The DF1704 is very good. TI/BB created it at the same time they created the "companion" PCM1704 multi-bit DAC; strangely, the PCM1704 has a built-in DF. In the datasheet, they still recommend the add-on DF1704 (for use with PCM1704) for optimal results.

" Is there a better filter then [sic!] DF1704"?
Well, from the same era, probably PMD100 or PMD200. Though I've found that if you supply DF chips with really clean, well-reg'd power, with heavy near-chip decoupling ...these techniques alone are more important than chip manuf./model. My much-modded Magnavox CD-650 still remains my reference for digital playback ... i.e., despite its ancient chipset: TDA1541A (single) and SAA7220/B.
A diy superclean+tight external PSU is one reason for good sonics.

Or you could go custom DSP (ala Wadia, Theta). You do know your math and how to code, don't ya?

[naimless]

Originally Posted by elektroj

Jaffrie,
Sound-wise SM5803 is only so-so. DF1704, in contrast, is fine filter, but it won't work with UltraAnalog modules without some additional glue logic. UA DACs need filters that have 'De-glitch' output.
Three candidates that come to mind are SM5842, SM5847 and PMD100.
(I know the DF1704 quite well, I've fitted it to many different CD players/DACs over the last 10+ years. In fact, everything that the German 'company' you've mentioned was/is selling was designed/manufactured by me. All the later versions by him are reverse engineered knock-offs of mine, so I can't say whether they will work as expected or not..)

Hi Electroj,

I need your opinion on digital filter, I currently have a STAX Talent DAC, and wondering any compatible Digital Filter you could recommend for direct replacement to upgrade the SM5803?

Appreciate your assistance. Thank you.

Naimless

[canvas]

Originally Posted by hollowman

strangely, the PCM1704 has a built-in DF

Well, I didn't see that in the datasheet. If it has DF inside, it will need extra clock or PLL circuit.

Poting

[abraxalito]

Originally Posted by canvas

Well, I didn't see that in the datasheet.

That would be because it isn't there .

Anyone here have any interest in a 'soft' digital filter using a CPU? Nowdays signal processing has become so much more affordable and lower power. Take these chips for example from ST - https://www.st.com/content/st_com/en...h7-series.html

STM32H730 looks to be a good choice, and under $5 in quantity. I'm fairly sure it can be coaxed into making a better digital filter than anything off-the-shelf.