GUSTARD DAC-R26 Balanced Decoder R2R+1Bit Dual Native Decoding Music Bridge

[camrector]

Those emails are even clearer than I recalled!

Btw I would say although @sajunky can be a bit blunt at times (much like some Saffa mates of mine!) he is a knowledgeable and well intentioned guy who makes valuable contributions to a number of other threads I'm on. So I'm always interested in his take.

This discussion and a bit if challenge is always healthy if we can try to keep it chilled - maybe @m-i-c-k-e-y could sticky the outcomes (schematics, Gustard emails... anything else) on his OG post.

Oh for sure no offense taken or given!

About a 1000 posts back when I went deep down the R26 rabbit hole, I was totally bummed to find this information out.
They could have done the multibit DSD within the FPGA or added another Delta modulator.
They choose to have only a direct unchanged 1bit DSD path. Just like with NOS pcm.
I can understand the reasoning. You can upsample in software and have the R26 play that purely untouched.
To me all these DSD conversion are messy and each stage stands the chance to change the high frequency response making it slightly brighter or muted. And what to do with all the ultrasonic information in DSD in these format conversions. It is like taking four pre-amps of different designs and cascading them together.

 

[camrector]

Fully support this. When you speak to Gustard, attatch this photo and ask them why is the entire section resistors for decoding multibit DSD if not used!.

Maybe these Gustard guys refer you the to a developer, they will not spread a nonsense anymore.

Dude you have given zero proof of what you are saying. Except circle a random part of a resistor ladder and claiming it’s for multibit decoding. That’s the only nonsense I see here.
I’ve shown you the actual signal path sent to me by a Gustard engineer as well as his comments about how the R26 works.
I was disappointed to learn this too.

 

[Deleeh]

Hello,
Here is an excerpt from the manual on what DSD On/Off does.
Personally, I hardly hear any difference between the two modes and still prefer DSD ON.
It sounds more magical to my ears, I think the attacks come out better and also the silky sound from the instruments and the placement also seems to be a bit better.
I would recommend setting it to what you like best.
There may be differences in personal equipment where one mode may be more effective or better suited. I would personally keep that in mind.

From Gustard r26 Manual V1.2
Default is OFF. Turn on to bypassing the internal interpolating FIR filter. The raw DSD stream is sent into the R-2R ladder directly. *the volume adjustment is bypassed in this mode, so it is better to decrease the volume of amplifiers before enter this mode. With the improvement of devices’ performance and algorithm diversity of playback software, audiophiles can use highperformance PC to carry out digital oversampling filtering. Through the ports support high sampling rate(USB, IIS, LAN), the processed signal is directly sent into R-2R decoding ladder. Different from the built-in algorithm, software digital filters may provide higher sound quality and different listening experience.

 

[sajunky]

From Gustard r26 Manual V1.2
Default is OFF. Turn on to bypassing the internal interpolating FIR filter. The raw DSD stream is sent into the R-2R ladder directly.

This is all correct, and I know from a past how bad bitstream decoding sounds, they know it too. It is why they suggest upsampling to a higher frequency when using this mode.

 

[Dandoudou]

From Gustard r26 Manual V1.2
Default is OFF. Turn on to bypassing the internal interpolating FIR filter. The raw DSD stream is sent into the R-2R ladder directly. *the volume adjustment is bypassed in this mode, so it is better to decrease the volume of amplifiers before enter this mode. With the improvement of devices’ performance and algorithm diversity of playback software, audiophiles can use highperformance PC to carry out digital oversampling filtering. Through the ports support high sampling rate(USB, IIS, LAN), the processed signal is directly sent into R-2R decoding ladder. Different from the built-in algorithm, software digital filters may provide higher sound quality and different listening experience.

Now I remember that when I read the manual, I understood that there are ladders for DSD.
After that, the e-mails from Gustard said that there's a 1 Bit DAC for DSD.
These are contradictions in their communication.

 

[camrector]

This is all correct, and I know from a past how bad bitstream decoding sounds, they know it too. It is why they suggest upsampling to a higher frequency when using this mode.

Sort of correct. It doesn’t go to the R2R ladder.

 

[Jake2]

Now I remember that when I read the manual, I understood that there are ladders for DSD.
After that, the e-mails from Gustard said that there's a 1 Bit DAC for DSD.
These are contradictions in their communication.

I think this is one thing we can all agree on!

Three sources of Gustard info so far:

• Specific email clarifications to @camrector
• Gustard manual as above
• R26 product webpage text & images re '1 bit DSD circuit', which AfterDark call a Sony 1-bit DSD circuit.

 

[sajunky]

Sort of correct. It doesn’t go to the R2R ladder.

You are wrong again, it does as stated in the manual. It drives one bit only from this ladder: MSB.

EDIT: not one bit, but all together representing a maximum output voltage.

With a Direct DSD off, decoding is made on a separate DSD ladder (which I marked on the photo), the same as in most other DACs, including all modern Delta-Sigma chipDACs.

 

[Dandoudou]

You are wrong again, it does as stated in the manual. It drives one bit only from this ladder: MSB.

With a Direct DSD off, decoding is made on a separate DSD ladder (which I marked on the photo), the same as in most other DACs, including all modern Delta-Sigma chipDACs.

The manual says that decoding is made on a DSD ladder when DSD Direct is turned on:

"Default is OFF. Turn on to bypassing the internal interpolating FIR filter. The raw DSD stream is sent into the R-2R ladder directly."

 

[Deleeh]

No, I suggest that you set up your R26 the way you prefer and like it on your system.
The same goes for sampling, whether it's DSD or not or just Pcm is up to you.

As I see it, everyone has his own sampling rate where he prefers there is nothing wrong with it, just as another prefers DSD, to each his own.

Personally, I stuck to what the instructions said and decided on a preference.
Everything else may have been pulled out of thin air by Gustard support, we don't even know who is behind it or who really has the technical understanding of the R26.

I wrote to them a couple of weeks ago about the Attenuion thing and still haven't received a reply.
As long as this is going on and Roon and Audirvana are contributing to it, there is no reason to write again.

Set the R26 the way you personally want it and enjoy the rest of the sessions.
That's actually what it's made for - there's still plenty of technical gadgetry to enjoy.

 

[camrector]

You are wrong again, it does as stated in the manual. It drives one bit only from this ladder: MSB.

With a Direct DSD off, decoding is made on a separate DSD ladder (which I marked on the photo), the same as in most other DACs, including all modern Delta-Sigma chipDACs.

Dude again you have zero proof of what you are talking about.
The 1bit DSD DAC is completely a completely different module and has zero to do with the R2R ladder.
Look at the schematic provided by Gustard.
The Gustard engineer has said that you are not correct, in several different ways.

Here is more proof from Gustard
Native DSD
Native PCM
DSD to PCM

Show me then the setting on the R26 to convert DSD to PCM!
Further more this pic from AfterDark shows a slightly different board and arrangement than those random resistors you circled. Zoom in. I don’t see those little gold blocks you circled.

I would love for you to be right here.
I thought the same thing as you UNTIL Gustard showed me otherwise.

 

[sajunky]

The manual says that decoding is made on a DSD ladder when DSD Direct is turned on:

"Default is OFF. Turn on to bypassing the internal interpolating FIR filter. The raw DSD stream is sent into the R-2R ladder directly."

How you can say so? It says clearly R2R ladder.

 

[BShaw]

Here's a shot of the board of my R26, at least you guys can continue to argue about a photograph of a real unit:

 

[Dandoudou]

How you can say so? It says clearly R2R ladder.

I'm saying that the manual says that DSD is processed by a R2R ladder when DSD Direct is turned ON.
You said OFF.

 

[sajunky]

I'm saying that the manual says that DSD is processed by a R2R ladder when DSD Direct is turned ON.
You said OFF.

?