USB to I2S conversion and reclocking quality doubt

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When I originally started to play around with DDCs, I figured up-stream quality didn’t matter so much as the DDC’s high quality clock and power supply would output a clean signal. Although that seems intuitive, I found out that was NOT the case; improving the quality of the source (adding an ATX LPSU, removing SSD power, installed a PPA OCXO controller) also improved the quality after the DDC. Indeed, using a 5v battery vs a LPSU on the PPA by itself makes a difference even though you would think the DDC output wouldn’t change.

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The very reason why people’s systems get cluttered with boxes is because they all make a difference. That’s why I’ve spent so much time and money in an effort to reduce my clutter building out a linear PSU PC, battery-powered PPA V3 card direct into a DSD512 DAC — the concept is I try to provide the cleanest source possible without the need for conditioners, isolators, re-clockers, etc. I haven’t even addressed the network side of things.

 

 So,  to answer the question is it a waste of money — no, this is an area in which money is well spent. A much more important question is your strategy.

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1 hour ago, doraymon said:

Thanks.

Yeah my strategy depends on my understanding of the topic, which at the moment is quite poor.

And I seem to have unleashed some sparkles for strong discussion. It was not my intention.

I am sure these are things that cannot be explained in a forum, but maybe I can get some direction so that I can find more material to read.

 

CA is on the leading edge of this topic -- although General is the hangout of the non-audiophiles.

 

The information buried in large threads in the DAC and Music Server forums. That's a lot of reading. Simplified:

 

1. It's all about managing noise getting into and out of the key parts of your audio system.

2. Sources of noise: mains, switching power supplies, storage devices, motors, processors.

3. Elements of noise control: cleaning mains power, eliminating ground loops, eliminating/cleaning storage device power, eliminating switching power supplies and mechanical sources.

4. Considerations specifically for digital audio links: keeping a PC/server/streamer's noise OUT of the DAC while increasing the signal quality leading into the DAC. The DAC can create self-noise by the interface controller working trying to clean up a bad signal. Outside noise will negatively impact the DAC's input circuitry and overall performance.

 

The strategy consideration is how you go about dealing with it. Many people here go the external storage -> network isolation -> streamer -> DAC route. The key benefits are that by using a network device like a server or a NAS to store the music, you keep its noise far away from the DAC while a very low-power, low-noise streamer is responsible for feeding the DAC a high quality signal (typically also going through some form of USB or SPDIF conditioner). The network isolation technique is used to eliminate any noise being transmitted via the network.

 

Others that don't want to spend so much and/or have so many boxes to deal with just go straight from PC to DAC with significant USB conditioning in-between. This typically includes a power-blocker, high-end cable, re-clocking, etc.

 

Others, like myself, try to clean up the source as much as possible (linear power supplies, advanced clocks, boutique controllers, filters, etc and so on).

 

Some quick tips:

1. Switching power supplies are the devil, linear power supplies are good.

2. Batteries provide clean power and will also never cause ground loops. Stuff with 5V inputs can be powered by common USB power packs.

3. Clocks from better to best: VCXO, TCXO, OCXO.

4. Addressing USB noise and signal quality is essential.

5. Cheapest way to clean up the mains: run your audio gear off an un-used circuit.