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PostPosted: June 16th, 2021, 3:51 pm 
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Cogito wrote:
Sound quality is a subjective matter. If you have a DAC that supports Nativs DSD and DoP, we can evaluate them on Saturday.


In both cases the DAC chip is going to receive exactly the same bits unless something is broken....

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PostPosted: June 16th, 2021, 4:04 pm 
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DoP involves lot of extra processing as 1bit DSD stream is encapsulated in 16-bit PCM packets for transmission.

Think of it as a regular laptop running 100s of programs streaming music to DAC vs a dedicated Linux machine. In both cases the DAC receives same data, but we know later sounds better.


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PostPosted: June 16th, 2021, 9:28 pm 
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Shashi,

From what I have read, DoP encapsulates 16bits of 1 bit DSD within 176kHz/24bit frame with a 8 bit pad. This is actually not unlike how ethernet is transmitted in terms of data encapulation with a frame with header information. I would think the process to strip off the padding and reassemble the DSD bit stream would be a very low overhead process. From what I have read, there is no discernable impact on sound quality regarding DoP vs direct DSD.

David


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PostPosted: June 17th, 2021, 8:03 am 
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David,

I see DoP compared with network packets on the interweb. That is an excessively simplified comparison.

Within the DAC, PCM is clocked at frames length (24 or 32bits) and DSD is clocked at bits. I looked at ESS and AKM IC specs. ESS9038 has capabilities to handle DoP within the IC where as AKM does not. This means for AKM, the DoP to DSD conversion has to be done in XMOS and the DSD stream has to be fed to the AKM IC.

In the AKM DAC I tried, I preferred Native DSD over DoP. That was about 4-5 years ago. At that time, I did not have the audio grade USB card. The XMOS implementation was possibly the cause of the difference. But, we have to view xmos as part and parcel of the DAC.

I am reading about Chord/DAVE. I suspect DAVE does not use any DAC ICs, instead built the DAC using a bunch of microcontrollers. Chord may have chosen not to support DSD transportation as it increases complexity but instead spend efforts on perfecting the D/A conversion.


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PostPosted: June 17th, 2021, 8:51 am 
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Shashi,

The Chord products use FPGA using custom designed filter and conversion firmware that is far more sophisticated than off the shelf DAC chips from AKM or ESS. The designer, Rob Watts, is an advocate for very high tap filters that reproduce transients with high accuracy, and using a very high stream rate to feed the DAC. The Chord Hugo M Scalar, for instance, uses as 1 million tap upscaling filter designed in an FPGA which is claimed to accurately recover the original analog waveform from 44.1kHz/16-bit PCM data, streaming it at 705.6kHz/24bit data to the DAC, which is the equivalent to DSD512. The data rate is beyond the capacity of USB, so uses dual BNC connection between the M Scalar and the Chord DAC (in my case, the DAVE). You can hear on Saturday what it does to standard CD resolution files.

David


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PostPosted: June 17th, 2021, 9:49 am 
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David McGown wrote:
Shashi,

The Chord products use FPGA using custom designed filter and conversion firmware that is far more sophisticated than off the shelf DAC chips from AKM or ESS.


Yup! thats what I gathered from Stereophile review.

Quote:
You can hear on Saturday what it does to standard CD resolution files.

David


Looking forward for it.


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PostPosted: December 21st, 2021, 8:58 am 
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I have the USBridge now. Who wants it next?


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PostPosted: December 21st, 2021, 9:12 am 
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David McGown wrote:
streaming it at 705.6kHz/24bit data to the DAC, which is the equivalent to DSD512. The data rate is beyond the capacity of USB, so uses dual BNC connection between the M Scalar and the Chord DAC (in my case, the DAVE).
David


USB works just fine up to 768k here with my TT2.....

Roscoe

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PostPosted: December 21st, 2021, 9:56 am 
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Roscoe Primrose wrote:
David McGown wrote:
streaming it at 705.6kHz/24bit data to the DAC, which is the equivalent to DSD512. The data rate is beyond the capacity of USB, so uses dual BNC connection between the M Scalar and the Chord DAC (in my case, the DAVE).
David


USB works just fine up to 768k here with my TT2.....

Roscoe


Wait, David is wrong? LOL

If no one wants it, I'm returning the bridge to you Mr. Roscoe!


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PostPosted: December 21st, 2021, 10:30 am 
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Stuart Polansky wrote:
Roscoe Primrose wrote:
David McGown wrote:
streaming it at 705.6kHz/24bit data to the DAC, which is the equivalent to DSD512. The data rate is beyond the capacity of USB, so uses dual BNC connection between the M Scalar and the Chord DAC (in my case, the DAVE).
David


USB works just fine up to 768k here with my TT2.....

Roscoe


Wait, David is wrong? LOL

If no one wants it, I'm returning the bridge to you Mr. Roscoe!


Could you send it to me so I can sell it for Jim?


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