Gain cell dac filters?


#1

I’ve been trying to find out which filters the gain cell dac uses. But nothing came up on the forum search.
So, what filters are used, how many choices and what is the sound difference between them?

Also, how are they implemented? As in, what does the filtering and where is it in the signal path?
Ps: I have a marantz hdamp1 with 2 filters. And I love the one and not the other.
Thanks in advance.
Danny


#2

(1) low slope linear phase, (2) high slope minimum phase, (3) high slope linear phase

Higher the slope = more ringing.

Linear has equivalent per-ring and post ring but has no phase issues.

Min phase has lower pre ring higher post ring and phase distortion.

There are digital filters in the ESS during the up-sampling stage to filter out aliasing.


#3

I would like to add that while additional sound quality can be had from DSD upconversion in Software, the built in filters are very musical and very well done.


#4

Okay, thanks for the responses!
I have another set of questions though. Why are there filters in the first place? Why is ringing there? What is it in the dac that makes these issues with phase and pre ringing?
Did dacs always have these problems, or are they modern dac problems?

Also, I’ve seen “impulses” in explanations, but in music what does pre ringing actually do?

Thanks again guys.
Danny


#5

If you don’t filter you won’t suppress aliasing so you will have tons of high frequency noise above Nyquist.

Linear phase have more latency thus produce pre-ringing which is a pre-echo. This can have a bad blurring effect if the filters are too steep. As long as the slope is low order the ringing is kept minimal. I believe linear phase produces more latency due to the more intensive math calculations to maintain phase coherence.

Min phase filters sacrifice phase so they are lower latency.

To my ears, min phase are not musical and sound analytical. I do not like the phase issues, instruments tend to have improper depth to my ears.

The only way you avoid these issues is by getting an R2R DAC which have no upsampling. In those DACs however you can’t play hi res or DSD formats, they are limited and quite $ in comparison. They also have other issues.