MSB support for DSD playback

[babybear]

Hi,

 

I see that MSB has just made available a new firmware version for its various DAC IV models that supports DSD playback. It appears from reading the description on their web site that it supports DSD over all of its supported digital inputs which includes USB but is also not limited to USB input only. This is good news for current model MSB Dac users.

 

Arnie

[DJS]

Works Great!

 

I have it up and running on my DAC IV using both Foobar2000 on my server and my MSB DVD player, the UMT, over S/PDIF (which just got a native DSD streaming firmware too). I don't have any opinions on sound quality yet but it does work perfectly without any glitches at all. It looks like they are using the DoP standard that all the new DACs are using... I wonder if you can use the UMT as a transport for them too. I might have to borrow my friends Mytek.

[babybear]

Thanks DJS,

 

I also have the UMT specifically for playing SACD's and I didn't even see that firmware upgrade for it. I will have to install both of these tomorrow and see how my SACD's sound now.

[DJS]

MSB did a nice job, their DSD implementation works well for double speed DSD too (using foobar, DSD128). I just finished listening to a nice direct to DSD recording in DSD128 that a friend of mine did, it was fantastic.

[barrows]

I am assuming thta MSB's implementation of DSD playback converts the DSD to PCM, right? After all, aren't MSB DACs all multibit R2R ladder style converters?

[babybear]

Barrows,

 

Your assumption is wrong given the new firmware upgrades. Previously, when using MSB's UMT transport, they did convert SACD's (DSD) to 32/176.4 PCM for playback via one of their DAC IV's and they could not process a DSD data stream directly into the DAC's. They released 2 firmware upgrades. One for the DAC IV's which plays back DSD natively (from any of their digital inputs) and also one for the UMT which now passes the DSD from an SACD natively to the DAC IV. I have done the upgrades to both and it works flawlessly. I do not know how they do what they are doing, but I have confirmed in speaking with them that they are playing the DSD natively and no longer do the PCM conversion.

 

Arnie

[barrows]

Hmmm? I do not doubt that MSB is no longer converting to PCM in the Universal Music Transport, but, a firmware update cannot change the physical topology of their DACs. I have always understood that MSB uses a proprietary, discrete, resistor ladder DAC design, made up of discrete, high precision resistors (the converter itself, not the DAC component).

Now, a resistor ladder style DAC is specifically for converting multi bit, PCM data streams, and to the best of my understanding, cannot convert a single bit DSD data stream to analog, for converting DSD, on needs a DAC (hardware, the actual converter itself) which is capable of doing so.

 

Perhaps I am missing something in my understanding here, I will go to MSB's site and try to figure it out, and perhaps make a direct inquiry with them as well.

[Miska]

Generally DACs can play either DSD or PCM natively, not both. But which one this DAC is, ladder or delta-sigma? I've understood MSB is ladder type, just as Barrows said.

[babybear]

Well, let us know when you figure it out. It would be surprising that MSB went to the trouble to develop, test and release new firmware for both the DAC's and UMT and then state that they are playing back the native DSD data stream if it wasn't technically possible. I can state that playing back SACD via the UMT with the new firmware does sound really, really good.

[DJS]

Most modern DSD converters are not single bit anyway. They are usually 3 to 6 bit running at between 2-12 Mhz. So when you play DSD through them they convert the 1 bit 2.8Mhz DSD to something like 3bit 5.6Mhz PCM. I know that the MSB 24bit DACs do up to 1.5 Mhz so I'm going to speculate that their "native" DSD is really 1.4 Mhz 24 bit PCM. But whatever they are doing the DAC accepts native DSD flawlessly and sounds great.

[barrows]

DJS: yes, partially true. But I do think it is reasonable to distinguish between DACs, and to have a real understanding of what is going on.

For instance, I know of a few DACs off of the top of my head which do convert DSD truly natively, at a single bit: EMM Labs, Meitner, and the exD/Sonore. There are still at least a couple of off the shelf DAC chips available which will operate in single bit mode for DSD, so it is possible for manaufacturers to relatively easily produce DACs which could convert DSD natively.

I think we also should distinguish between those DACs which are R2R, like the MSB seems to be, with true ladder converters, and those DACs (most of them now) which are sigma delta, and convert at 5-7 bits or so.

 

My understanding of the MSB leads me to believe they must be converting the DSD in the DAC to what I would consider a true PCM stream, at 24-32 bits, in order to convert to analog using their ladder DAC. I think this is quite different from the 5-7 bit, delta sigma approach used in the vast majority of DACs.

[DJS]

While its true the Meitner seems to convert DSD in something close to its native format (1bit 5.6Mhz) the Sonore uses the DSD1792 chip which is 4bit 5.6Mhz PCM. Even DCS DACs are more than 3 bit DACs. As far as I know if you want a currently produced "true" DSD DAC the Meitner and the Japanese Audiophile Societys 1bit DAC are your only choices.

[barrows]

While its true the Meitner seems to convert DSD in something close to its native format (1bit 5.6Mhz) the Sonore uses the DSD1792 chip which is 4bit 5.6Mhz PCM. Even DCS DACs are more than 3 bit DACs. As far as I know if you want a currently produced "true" DSD DAC the Meitner and the Japanese Audiophile Societys 1bit DAC are your only choices.

 

You are confusing two different DACs: the Sonore Signature DAC does indeed use the PCM1792. The Sonore/exD DAC uses a DAC chip (un published which one it is) which runs in single bit mode for DSD conversion. I believe the DAC chip in the exD is of Japanese origin, but I am unaware of the part number.

[DJS]

It seems your right, so with the Sonore/exD DAC we really don't know what's happening internally with DSD.

 

Still my point is it doesn't really matter what method you use to get from DSD to analog as long as the results sound good, and my DAC IV is sounding great playing back DSD atm. It sounds like I'll have to compare it to one of the other "native" DSD DACs to really judge MSBs implementation, I wonder if I can get my hands on a Meitner so I can have a listen...

[Miska]

Most modern DSD converters are not single bit anyway. They are usually 3 to 6 bit running at between 2-12 Mhz. So when you play DSD through them they convert the 1 bit 2.8Mhz DSD to something like 3bit 5.6Mhz PCM. I know that the MSB 24bit DACs do up to 1.5 Mhz so I'm going to speculate that their "native" DSD is really 1.4 Mhz 24 bit PCM. But whatever they are doing the DAC accepts native DSD flawlessly and sounds great.

 

They can play DSD natively by simply substituting all 1's by maximum internal sample value and 0's by minimum internal sample value, no change in sample rate. This way multibit SDM can work as completely native 1-bit DSD converter without performing further processing. Cirrus and Wolfson seem to work this way in Direct DSD mode.

 

Cirrus also has separate option to "upsample" DSD to higher rate.

[Miska]

It seems your right, so with the Sonore/exD DAC we really don't know what's happening internally with DSD.

 

If it uses CS4398 in Direct DSD mode, DSD goes straight to the actual conversion stage. IIRC, Wolfson WM874x can be used same way too.

[matthias]

If it uses CS4398 in Direct DSD mode, DSD goes straight to the actual conversion stage. IIRC, Wolfson WM874x can be used same way too.

 

Miska,

there is a comment on the sonore/exd thread regarding the chip:

 

"I really appreciate the comments and feedback! I just have a few details to clear up. Barrows did a great job at comparing the two DACs and I'll leave it that. exD had a DAC on there site back in 2011 that used a Cirrus DAC chip. The Sonore/exD DAC is a different design and does not use that DAC chip. It's true that I'm exploring an USB option to the Sonore Signature Series DAC. This option requires some power supply changes and will substitute the HDMI i2s input. The USB input prototype is being build and incorporates some additional upgrades. Linux Firewire into the Mytek is working out very nice thanks to Jurgen. Getting it working is not hard, but requires some command line persuasion.

 

Jesus R"

[Miska]

Miska,

there is a comment on the sonore/exd thread regarding the chip

 

OK, I don't have that DAC so I don't know. Photo on the web page doesn't have enough resolution. Maybe Wolfson then?

 

I've been using CS4398 quite a lot myself, so I know it very well.

[matthias]

OK, I don't have that DAC so I don't know. Photo on the web page doesn't have enough resolution. Maybe Wolfson then?

 

I've been using CS4398 quite a lot myself, so I know it very well.

 

If I am right there are two different EXD DSD DACs:

 

1.) The "original" exd dsd dac with the CS4398. This dac uses Damien from Audirvana.

2.) The Sonore /exd with another chip.

[barrows]

The DAC chip is not Wolfson either. All I could find out is that the Sonore/exD DAC uses an undisclosed chip of Japanese origin which converts DSD in a single bit process.

[catastrofe]

I just updated my DAC IV, and Jesus helped my update my Sonore server to a newer version of Vortexbox that supports DoP. DSD via my server thru the DAC IV sounds absolutely awesome!

[Miska]

The DAC chip is not Wolfson either. All I could find out is that the Sonore/exD DAC uses an undisclosed chip of Japanese origin which converts DSD in a single bit process.

 

Then it can be only AKM (but not AK4399, looking at the photo)? I cannot think of anything else... I don't remember which model would support DSD128 though. Or then there's just something I don't know about (of course entirely possible too).

 

In any case that's off-topic. If MSB is a PCM ladder DAC, then it likely has to perform some PCM down conversion. Of course it can sound good too...

[Miska]

OK, correction, digging through the information on MSB's website, I can think of a way to make DAC IV work even at DSD128 natively. They could get the same DSD performance for a lot cheaper with SDM DAC design though...