2. digital
  3. 180440-174247

DAC Input Topology

I have a Holo May DAC KTE and all digital in is captured by a proprietary PLL (phase lock loop) circuit which uses a crystal Voltage Controlled Oscillator (VCXO) and discrete voltage regulators to eliminate jitter.  They make clear that all inputs are processed the same.  Is this the primary method used by most (all) DACs?  
I ask because I was previously convinced that I wanted to buy a steamer with I2s out.  I was under the impression that a great clock in the streamer would be passed to the DAC, but PLL doesn’t use the streamer’s clock.  My fallback was USB and the May DAC KTE makes claims regarding the quality of their USB interface.  In fact USB is the manufacturers preferred input.   Now I’m looking at the Aurender N20.  The selling point here is the OCXO clock, which is four to ten times more stable than the Holo’s clock.  Many find the AES, or coax to provide the best sound.  Those that prefer AES, does your DAC use the same voltage driven clock PLL design?  How does the Aurenders clock provide superior sound when the sampling clock is an order of magnitude less stable?   I’m trying to decide on if I’m buying a high quality USB, or AES cable.  Maybe both at some point, but budget only allows one at this point.

vonhelmholtz

Showing 5 responses by vonhelmholtz

vonhelmholtz OP
911 posts
 

@designsfx 

It was stated in an article that I read which explained the differences in clock technology where it stated the OCXO was 4-10 more stable than other clocks.  Of course atomic clocks are better yet and really expensive.  Aurender has an external atomic clock that is more expensive than their flagship server/transport.

vonhelmholtz OP
911 posts
 

@jasonbourne52

I have an iFi Zen Stream and I’m trying to make sense of Aurender’s claims. My iFi Zen Stream has their top power supply and sounds good and sounded better than my previous analog system, but doesn’t match my analog whereas many Aurender systems compete with high end analog. I prefer Roon vs Conductor, but Aurender users, not all, seem taken with their higher end AES/coax outputs. I’m questioning if this is due in part to the methodology used to capture the signal.

vonhelmholtz OP
911 posts
 

@lowrider57

The streamer/DAC does not have an internal DAC. The significance of the stable clock is that it can produce an extremely low jitter on the AES/EBU, BNC and Coax outputs. I was questioning if the Holo can take advantage of this given that the clock quality/stability is very good, but 4-10 times less stable than the Aurender clock. Most N20 and higher owners prefer listening with AES/EBU vs USB where the DAC clock is responsible for keeping jitter low as it decides packets passed via USB.

vonhelmholtz OP
911 posts
 

@designsfx 

Yes, your understanding seems valid.  Perhaps at some point I will purchase a DAC with clock sync inputs, but good external clocks seem to be rather expensive.

vonhelmholtz OP
911 posts
 

I thank everyone for their input.

I purchased a used N20. I recognize that the value proposition for such a purchase is debatable. I will, at some point, report my experience with the N20.

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