iFi foe fum

[asdf1000]

32 minutes ago, mansr said:

They say it "was developed by iFi according to our specifications in conjunction with the MQA team."

 

51 minutes ago, Miska said:

So I'm wondering how much there is actually common ground between the two...

 

And they knew some of you would wonder this so they added: 

 

"We must make clear that GTO is not directly related to filter types used by MQA, it is not “MQA through the backdoor”

[asdf1000]

5 minutes ago, mansr said:

How is it then that the 96 kHz and 192 kHz versions are exactly the same as MQA filters found in the Bluesound firmware?

 

It is MQA through the backdoor? 😧

 

The good thing about the current iFi DACs is you have options to use other non-MQA related filters, so not too big a deal.

 

Hopefully it remains that way for future products.

 

[asdf1000]

1 minute ago, crenca said:

 

Just to be clear, if you want to avoid GTO filter then you have to download 5.3 (not 5.3C).  If you want to avoid GTO & MQA altogether, you have to download "5.2 & 5.2A, 5.2B ‘Limoncello’"  from here:

 

http://ifi-audio.com/downloads/

 

Yeh but none of that applies to Pro iDSD, their newest DAC.

 

There are non-MQA and non-GTO filters to choose from.

 

In addition to “bit perfect” and you can do digital filtering before the DAC if you want.

[asdf1000]

30 minutes ago, mansr said:

One problem. The DSD1793 works better with 192 kHz input than 384 kHz. This is because the 192 kHz input is upsampled 8x to 1536 kHz, greatly reducing the demands of the analogue filter (external to the chip).

 

And what happens with 384kHz input? Up-sampled to what rate?

 

Or it's not up-sampled to a higher rate?

[asdf1000]

7 minutes ago, mansr said:

I was talking about PCM only. DSD is a different kettle of fish with its own issues.

 

Can you share what these issues are, with feeding DSD256 to your iFi DAC?

 

[asdf1000]

On 3/18/2019 at 8:27 AM, mansr said:

In order to get a closer look at this magical filter, I connected a logic analyser to the inputs on the DSD1793 DAC chip. With this new firmware, the chip is put in filter bypass mode, the XMOS now upsampling everything to 352.8/384 kHz.

 

Hi mansr

 

As a baseline for comparison, can you share the same measurements with the DSD1793 doing the digital filtering , for this same DAC?

 

 

[asdf1000]

2 hours ago, mansr said:

The best I can do in that regard is recording the analogue output. I did that a while back:

 

Thanks. It's not easy to compare directly unfortunately. Different measurements.

 

I guess the background to my query is how much of these results is to do with the GTO filter itself?

 

Unless we can properly compare against DSD1793 chip performance of this DAC, it's hard to know for sure?