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SOTM USB card vs PPAstudio USB Card v2


Inbest

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It is not my money which buy this , I am not to approve or deny.

 

Just every engineer tries hard to keep the clock signal as precise as possible: minimizing routes, placing the clock generator right next to the chip, shielding, keeping the impedance of the clock source low etc. A bit like the original card - the crystal is right next to the chip.

 

What this "mod" does is the complete opposite - sharp edges of the clock board are being blurred by a bandwidth-limiting transformer, adding further jitter to the signal by catching all the PC EMI/RFI noise induced in the huge transformer (compare its size to SPDIF signal transformers often found on PCI soundcards), routes from the clock to the chip many times longer than the original connection, plain unshielded long wire carrying the signal.

 

But I understand - a product for audiophiles must boast an audiophile-grade transformer, spells like that sell. Interestingly, the professional SOTM card delivers without any transformer. And no wonder.

 

I sent this to Pang and here is his reply:

Hi,

My digital output transformer was hand made such like the audio note DAC5 special has been used.

Audio Note DAC 5 Special Review - Equipment Reviews - Dagogo

Please refer to the attachment

 

The precise clock is not only at the generator frequency offset,

The most important is at the wave form of the clock output.

 

My low jitter TCXO is not the PLL output,

With my digital output transformer,

My clock board will be offered the very low jitter and precise clock wave form output.

 

Thanks!

 

Regards

 

Pang.Kai-Yu

 

 

 

 

 

 

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If you are happy with such an answer then good for you. To me it sounds like a random compilation of technical terms. And I do not see any relevance to the DAC linked, its transformers are used for I/V conversion behind the DAC stage.

 

The clock waveform is exactly what will be ruined by the slow transformer inserted into path of the 24MHz clock signal.

 

I'm neither happy nor unhappy I thought your post was interesting and so decided to see what Pang said and that was his reply. He put this attachment (for the dac reference):

AudioNoteDAC5Special-JR-6.jpg

 

 

 

 

 

 

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  • 3 months later...

Priaptor

Could you clarify - you said the Micro version worked of the Intel board above (Intel DH77DF ?) which is a mini-ITX board. Did you mean the DH77EB (Zuma) micro-ATX worked?

 

What are the exact models of the one that worked and the one that didn't?

 

 

 

 

 

 

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  • 4 weeks later...

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