“Sigh”. When I was growing up, dancing in the end zone was considered bush league behavior. And dancing before you get to the end zone, just before you fumble the ball thru the end zone is just embarrassing.
When I respond to someone’s post, I really do try to give them the courtesy of reading and carefully considering everything they’ve written. I wish you would do the same. But here goes, one last time:
1) Re analog waveform - I never even responded to this point, because it’s not relevant to the points I was making.
2) Re Rex 3 DAC - I never opined on your specific DAC’s effectiveness at rejecting noise from a streamer. My responses were always conceptual. I would note however, that you might want to temper your confidence in your DAC if your views on this topic are informed primarily by the manufacturer’s marketing materials. That’s why, in the absence of effective measurements of such claims, I tend to maintain healthy skepticism, and suggest to other members that they may want to be safe, rather than sorry, and invest in a steamer that’s quieter than a Radpberry Pi, for instance.
3) How is noise getting from a streamer using asynchronous usb into the DAC. Here, I’m just gonna cut and paste from my prior post in hopes that you’ll read it this time.
“Even with asynchronous USB, several noise paths remain:
1. Power Noise via USB 5V
USB cables include a 5-volt power line. A noisy streamer (like a computer or cheap switching PSU) can send:
• switching noise
• RF noise
• ground ripple
into the DAC.
Good DACs often ignore this power line or regulate it internally, but not always perfectly.
2. Ground Noise
USB connects the grounds of both devices.
This can allow: • ground loops
• digital switching noise
• RF interference
to propagate into the DAC circuitry.
3. Radiated RF Noise
Even if the data is clean, the USB cable itself can act like an antenna carrying RF noise into sensitive analog sections of the DAC.
Why Many Modern DACs Handle This Well:
High-quality DACs often include:
include:
• USB isolation chips
• galvanic isolation
• reclocking
• local linear regulation
✅ Bottom line:
• Asynchronous USB fixes timing/jitter issues.
• It does not guarantee electrical isolation.
• Noise from the streamer can still reach the DAC, though good DAC designs minimize it.”
