HOLO Audio Spring DAC - R2R DSD512

[gsquared]

Cool tboooe! My new Level 3 has been warming up for a week in my system. Planning to put ears on it for the first time this weekend.

 

Happy New Year Alex! Any initial impressions on your Holo Level 3 DAC yet? I ordered one just a few weeks ago and just got word from Tim that it was shipped out - about a full month EARLIER than Tim estimated! Awesome service!

 

Anyway... looking forward to hearing your impressions of your DAC.

[Superdad]

Happy New Year Alex! Any initial impressions on your Holo Level 3 DAC yet? I ordered one just a few weeks ago and just got word from Tim that it was shipped out - about a full month EARLIER than Tim estimated! Awesome service!

 

Anyway... looking forward to hearing your impressions of your DAC.

 

Hi Gary! Great to see you here again. Yes, Tim has been terrific and I think he will go far with his good service.

 

Automotive repairs and other house chores took over my weekend--along with a ping-pong tournament with our kids--so I never managed to get an ear on the Spring DAC just yet. This week for sure.

 

All the best,

--Alex C.

[GUTB]

Look elsewhere because this thing doesn't do DSD, being a R2R ladder design. It converts DSD to PCM, lol.

 

 

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[rajacat]

Look elsewhere because this thing doesn't do DSD, being a R2R ladder design. It converts DSD to PCM, lol

 

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On the contrary, the Spring does do DSD.

Read ted b's excellent review.

Computer Audiophile - Holo Audio Spring Level 3 Kitsune Tuned Edition R2R DAC Review

[GUTB]

The statement that it processes DSD through a dedicated R2R ladder is of course a lie because R2R networks can't work with 1 bit streams.

 

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[barrows]

The statement that it processes DSD through a dedicated R2R ladder is of course a lie because R2R networks can't work with 1 bit streams.

 

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Actually, you will need to look a little deeper technically. Your statement above borders on being libelous.

[GUTB]

Actually, you will need to look a little deeper technically. Your statement above borders on being libelous.

 

R2R ladders can process 1-bit streams?

 

 

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[barrows]

R2R ladders can process 1-bit streams?

 

 

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Do some research on the Holo DAC, you will be surprised. They detail this on kitsune website.

[mansr]

R2R ladders can process 1-bit streams?

 

You could send the 1-bit stream to the MSB (or all the bits). The ladder aspect is obviously irrelevant.

[GUTB]

What I read on their site is that it converts DSD to PCM. Which makes sense as R2R ladders work by comparing bits of a digital audio stream in order to produce an analogue signal, meaning that using this method to decode DSD is impossible. The separate native DSD dual ladder board blurb is simply a LIE or at least misinformation by someone's bad translation.

 

 

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[tboooe]

Guys, I would love a layman's explanation of how this DAC handles DSD. According to the Kitsune website

 

. This is not the DSD converted to PCM before digital-analog converter, but directly by the discrete components of the DSD digital to analog converter

[GUTB]

Here it is from the horse's mouth: "So, now you should know, DSD native is just about the way it transfers the stream. Not describing the way it does digital to analog conversion. At the DAC stage, the DSD stream can convert to PCM then do the final digital to analog conversion. Actually, most DAC chips do this inside the chip. One point needs to be remembered, DSD streams can’t do volume attenuation. If this chip can do digital volume control under DSD mode, then is must converted to PCM already."

 

 

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[mansr]

Here it is from the horse's mouth: "So, now you should know, DSD native is just about the way it transfers the stream. Not describing the way it does digital to analog conversion. At the DAC stage, the DSD stream can convert to PCM then do the final digital to analog conversion. Actually, most DAC chips do this inside the chip. One point needs to be remembered, DSD streams can’t do volume attenuation. If this chip can do digital volume control under DSD mode, then is must converted to PCM already."

 

Some DAC chips have two modes for DSD, one with volume control via PCM conversion and a direct mode without. The bit you quoted only states that various options exist without detailing what this particular DAC does.

[barrows]

Here it is from the horse's mouth: "So, now you should know, DSD native is just about the way it transfers the stream. Not describing the way it does digital to analog conversion. At the DAC stage, the DSD stream can convert to PCM then do the final digital to analog conversion. Actually, most DAC chips do this inside the chip. One point needs to be remembered, DSD streams can’t do volume attenuation. If this chip can do digital volume control under DSD mode, then is must converted to PCM already."

 

 

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Huh? What does this have to do with the Holo DAC? There is no volume control with this DAC...

[GUTB]

You guys are trying too hard. That quote is from Jeff Zhou, the guy who designed this DAC. He admits DSD native refers to how the Spring accepts native DSD streams, and then clarifies that it's converted to PCM for actual A/D conversion. What follows is just excuses/apology as to why it doesn't really do native DSD (i.e., most other DACs don't either).

 

The fact is this: R2R ladders can't deal with 1-bit streams because it requires multiple bits to compare with in order to generate the analog signal.

 

 

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[barrows]

You guys are trying too hard. That quote is from Jeff Zhou, the guy who designed this DAC. He admits DSD native refers to how the Spring accepts native DSD streams, and then clarifies that it's converted to PCM for actual A/D conversion. What follows is just excuses/apology as to why it doesn't really do native DSD (i.e., most other DACs don't either).

 

The fact is this: R2R ladders can't deal with 1-bit streams because it requires multiple bits to compare with in order to generate the analog signal.

 

 

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Hmmm, the following quote appears to say that the discrete network converts a DSD single bit stream directly, also from the designer:

 

"Let's go back to Spring. If Spring works in 'NOS' mode. There is no

oversampling, no conversion, just the original data doing the final digital

to analog conversion. I will not explain how it does PCM conversion, you

should already know quite well about it. There is a lot of resistor ladder

DAC, they are born to do this. I just explain how Spring can do 'discrete

DSD conversion'. Actually it is like DCS and CHORD. If you looking to DCS

and CHORD's pcb, you will find 'discrete DSD conversion' is also using

switches and precision resistors, like resistor ladder dacs. So, no matter

it is 'discrete DSD conversion' or 'discrete PCM conversion', they all use

the same discrete devices. Just work in different architecture. That makes

possible to combine these two modes in one device."

 

Take a look at the block diagrams for the Mola Mola DAC, it uses discrete shift registers for direct single bit conversion, although at a very high rate. I agree that a typical R2R or "sign magnitude" R2R is not capable of single bit conversion, but Holo appears to be doing something different for DSD conversion. Although the ESL nature of the designers statements may also be obscuring some details.

[Jud]

ISTR Miska saying Chord's implementation involved converting DSD input to PCM internally, so when using HQPlayer with Chord DACs it was best to set it to send max rate PCM to the DAC. If Holo Spring is doing the same....

 

 

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[barrows]

ISTR Miska saying Chord's implementation involved converting DSD input to PCM internally, so when using HQPlayer with Chord DACs it was best to set it to send max rate PCM to the DAC. If Holo Spring is doing the same....

 

 

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Chord DAVE appears to operate its discrete "pulse array DAC" at 5 bits. But like ESS, saying it converts to "PCM" is problematic: question: is a DAC really converting to PCM if the data rate itself is not reduced, that is, say it takes in DSD 2.8 MHz, and then oversamples to a much higher rate (like Chord or Mola Mola) is that really PCM conversion? It seems a matter of semantics at that point to me. If it converted a DSD stream to 352.8 kHz that would be one thing, but...

 

Anyway, if the designers quote I posted is right, it appears in NOS mode the Holo DAC just sends a single bit DSD stream to the "discrete converter" directly with no further processing: certainly this is not PCM conversion...

[Jud]

Chord DAVE appears to operate its discrete "pulse array DAC" at 5 bits. But like ESS, saying it converts to "PCM" is problematic: question: is a DAC really converting to PCM if the data rate itself is not reduced, that is, say it takes in DSD 2.8 MHz, and then oversamples to a much higher rate (like Chord or Mola Mola) is that really PCM conversion? It seems a matter of semantics at that point to me. If it converted a DSD stream to 352.8 kHz that would be one thing, but...

 

Anyway, if the designers quote I posted is right, it appears in NOS mode the Holo DAC just sends a single bit DSD stream to the "discrete converter" directly with no further processing: certainly this is not PCM conversion...

 

Howdy my friend, hope you're having a good New Year.

 

Just wanted to make it clear I don't know anything about what either the Chord or Holo Spring do internally. My impression of what Miska was saying about Chord comes from posts like http://www.computeraudiophile.com/f22-networking-networked-audio-and-streaming/hqplayers-network-audio-adapter-13892/index51.html#post603500. But of course I personally cannot vouch for any details.

[GUTB]

Guys, the designer of the Spring says what it does -- converts DSD to PCM.

 

 

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[Miska]

Chord DAVE appears to operate its discrete "pulse array DAC" at 5 bits. But like ESS, saying it converts to "PCM" is problematic: question: is a DAC really converting to PCM if the data rate itself is not reduced, that is, say it takes in DSD 2.8 MHz, and then oversamples to a much higher rate (like Chord or Mola Mola) is that really PCM conversion? It seems a matter of semantics at that point to me. If it converted a DSD stream to 352.8 kHz that would be one thing, but...

 

At least Mojo and Hugo seem to be decimating DSD to 352.8k PCM and then converting it back up again. At first I thought Mojo would be doing it to 705.6k since it can also accept that as PCM input, but that doesn't seem to be the case. Unfortunately the decimation digital filter also seems to be quite poor, so it aliases quite a bit of noise down.

 

So just better send as fast PCM as possible to Chord.

[Miska]

What follows is just excuses/apology as to why it doesn't really do native DSD (i.e., most other DACs don't either).

 

The fact is this: R2R ladders can't deal with 1-bit streams because it requires multiple bits to compare with in order to generate the analog signal.

 

There's quite a number of DACs that can do direct DSD conversion. Since those are delta-sigma DACs and not R2R ladders, it is just matter of sending the bitstream to the actual conversion element network. Examples of such DAC chips can be found for example from TI/BB, AKM, CirrusLogic/Wolfson. Plus of course now various discrete implementations.

[Miska]

What I read on their site is that it converts DSD to PCM. Which makes sense as R2R ladders work by comparing bits of a digital audio stream in order to produce an analogue signal, meaning that using this method to decode DSD is impossible. The separate native DSD dual ladder board blurb is simply a LIE or at least misinformation by someone's bad translation.

 

I gave it a short thought when I heard about it and I could immediately think of a way how to turn R2R ladder into a typical delta-sigma (DSD) DAC if it is taken into account at the design phase. It either needs a small rearrangement where the switch is placed in the network, or alternatively way to switch the summing network out and replace it with just plain I/V converter. Then rest is about data arrangement when sending it to the conversion which is completely bit-perfect operation. Then it becomes just like for example my DSC1 DAC design which uses 32 conversion elements. But one could as well use 24 like dCS does.

[Miska]

What I read on their site is that it converts DSD to PCM. Which makes sense as R2R ladders work by comparing bits of a digital audio stream in order to produce an analogue signal, meaning that using this method to decode DSD is impossible. The separate native DSD dual ladder board blurb is simply a LIE or at least misinformation by someone's bad translation.

 

I gave it a short thought when I heard about it and I could immediately think of a way how to turn R2R ladder into a typical delta-sigma (DSD) DAC if it is taken into account at the design phase. It either needs a small rearrangement where the switch is placed in the network, or alternatively way to switch the summing network out and replace it with just plain I/V converter. Then rest is about data arrangement when sending it to the conversion which is completely bit-perfect operation. Then it becomes just like for example my DSC1 DAC design which uses 32 conversion elements. But one could as well use 24 like dCS does.

 

I don't know what the DAC in question does, but at least I know precisely how I would personally do it if I wanted to.

[xiddox]

Has anyone used a Pink Faun I2S bridge to drive the Spring DAC?

 

OK, I have it working now... turns out i had the wrong audio device selected (ahem) - in my defence, the pink faun just appears as another generic audio device....

 

So now I am fighting with Miska's NAA under Windows. It took me a while to figure out that NAA only supports ASIO drivers under Windows (some documentation would be nice), so I just installed ASIO4ALL and pointed it at the Pink Faun device, but NAA crashes when I start playing music. I've had enough for one night. I'll take a closer look and try again tomorrow. If I can't get it working quickly, I'll probably install Linux on another partition and see if I can get that working.