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What's up with all those clocks

I am using a PS audio perfectwave MKII DAC and could not be happier (with the DAC that is). The last frontier for me is room correction, so I am now auditioning a Trinnov 4 channel processor in an 2.2 actively crossed-over setup.

So I go from digital source -> Trinnov digital processor -> PS audio DACs. If I decide to continue down this path, I can no longer use my PS audio bridge for network streaming of my music library, and have to move to music server with AES/EBU out to feed the Trinnov instead. The server options are a decicated box like Bryston or Sonore, or a PC/MAC with USB to AES/EBU converter.

If I keep the Trinnov and go the USB converter route, this opens a whole new world of possibilities to sink more money into my system, which is where my question comes in. For now, lets focus just on clocks.

The first clock in the chain is in the Mac/PC, the second in the converter the third in the trinnov processor, and the fourth in the DAC.

Just before the bits hit the analog board in the DAC, all jitter gets eliminated in the brilliant brand new MKII board of the PS audio dac, so you could argue, why bother spending lots of money on any clocks downstream - just let the Perfectwave clean up the digital signal. Is this the case?

If the downstream clocks don't matter argument is false (which it probably is), I can now spend an inordinate amount of money on say an offramp USB converter with upgraded clocks at the beginning of the chain. How much of a difference would this make downstream, given all the other clocking going on downstream. Could I just get a basic $200 - $500 converter, or is with worth going all out.

To add insult to injury, the Trinnov has an external clock option. What would this do for sound quality, (A) if I had a so so USB converter, and (B) if I had a SOTA USB converter?

In summary, can anyone explain how quality of clocking at various point in the chain will impact final SQ, and how I can best allocate my "clocking funds".

I can formulate a similar question for "power supplies". This hobby is borderline insanity....
edorr

Showing 5 responses by audioengr

audioengr
3,282 posts
 
Ed - Features dont equal performance, neither do parts. It's the whole package, including the implementation. What do you think JA uses?

Steve N.
Empirical Audio
audioengr
3,282 posts
 
"Steve, why aren't you building a version of the offramp with external clock input? This would alow synching up your converter with downstream digital processors with clock inputs."

This would require a PLL or VCO clock. These have inherently higher jitter. There is no way that I could get to the jitter levels I achieve with these kinds of clocks. The clock must be free-running and stable.

Besides, the clocks in these DACs are not as good as the clock in my Off-Ramp 4. If you want to go inside the DAC and mod the clock and clock power supply, then maybe it would be competitive.

Steve N.
Empirical Audio
audioengr
3,282 posts
 
"can anyone explain how quality of clocking at various point in the chain will impact final SQ, and how I can best allocate my "clocking funds"."

This depends on the mode that you use for the PWD. If you use resampling mode or NativeX mode, then it is using internal clocks, so the effect of a low-jitter input will be less, but still noticable IME. It's strickly marketing that says that all jitter is eliminated. Never happens.

I have yet to find a DAC that is not improved by a low-jitter source.

If you use Native mode, then the jitter of the source is critical. This mode feeds the D/A directly. This is where a low-jitter input can make a huge difference. Feedback from one PWD owner demonstrates that on this forum.

If the Trinnov has an external word-clock input, it means that the internal clocks are PLL controlled, which will cause higher jitter. The good news is that a reclocker can easily be inserted after the Trinnov to remove the jitter. The reclocker can drive the word-clock input on the Trinnov and synchronize it to the reclocker. This allows a free-running clock to be used in the reclocker, delivering the lowest jitter datastream.

Steve N.
Empirical Audio
audioengr
3,282 posts
 
"To what extent would this impact the end SQ result if most jitter is eliminated downstream, just before the DAC?"

Anybodys guess is as good as mine. It may have no impact. If you try different sources and cables with the Trinnov and the sound is different with any of them, then there is your answer. It can probably be improved with a low-jitter source into the Trinnov.

Steve N.
Empirical Audio
audioengr
3,282 posts
 
ED - Adding a Pace-Car just complicates things. It would not improve the jitter. There is already a free-running master clock in the Off-Ramp 5.

The DAC is already a slave to the Off-Ramp 5, so the DAC is on the same clock, whether you use S/PDIF, AES/EBU, I2S or HDMI.

If you are talking about making the DAC the master and the source the slave, this would be worse. The clock in the DAC is just not good enough like I said, unless you mod it.

Steve N.
Empirical Audio
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