I have found an improvement in SQ between my two digital music sources

The point being is you want more power than is needed, just like with PS in Amplifiers, etc. The less the PS is stressed, the less noise.
Unless you're using a linear, that's simply note true. Switch mode power supplies are inherently noisy.

350 watt is great if you are running a laptop CPU and not much else but when you have a CPU that can draw 125 to 200 watts by itself and a video card that also pulls 250 watts, that little 350 watt PS is being pushed to it's max.
My desktop isn't stressed at all. Here's the math:

The i7-860 draws 85 watts at idle and averages 150. Nvidia GT740 video card draws 64. Samsung EVO 850 SSD draws 30 mW. Seagate Barracuda drive draws 5.

I guess computers must follow different laws of physics.
Your components must be real power hogs!
 
Why would music data be any different that regular data? Noise corrupts both

The difference between 'regular data' and 'music data' is that noise on the music data connection can couple into the analogue domain. Noise on a word file doesn't couple into the word document. In both cases, we assume perfect digital data transmission, so data bit corruption is not an issue (there are mechanisms to detect and correct errors, too). If you have residual bit errors, then you have bigger things to worry about...

The trick with digital to analogue data streams is to stop noise on the digital signal coupling into the analogue domain. That noise can be carried by electrical means, or timing means.
 
The real question is how is any of the noise present making it through the USB connection, which is all digital (So noise is irrelevant unless it's so bad that it's breaking up the recognition of the data) all the way to the analog chain. Regardless of the noise present internally to the PC, it has to get into the analog side of the DAC somewhere for it to cause an audible problem. So either:

1. Noise on the digital side is affecting the actual digital-to-analog process. In which case it seems there is insufficient filtering on the input side of the DAC chip or something is seriously askew in the signal to noise ratio there. Especially with an asynchronous USB protocol that's reclocking the data at the DAC, this seems unlikely.

2. Noise from the PSU is simply making it into the analog preamp circuitry inside the DAC. Which indicates improper filtering on the PSU side of the DAC. Is the DAC running off of it's own power supply when using SPDIF and off of USB power when using USB as the input? This could account for some of the difference. I wonder if a USB data-only cable could be created to isolate the PC's power from the DAC.

Either way, it's a failing in the DAC design. Noise in the USB power/signal should be accounted for during the design process of the DAC.
 
What protocol provides an improvement in performance over an asynchronous USB connection? SPDIF/Optical has issues with both jitter and ability to transmit better formats (DSD is quite limited over SPDIF for example).
 
What protocol provides an improvement in performance over an asynchronous USB connection? SPDIF/Optical has issues with both jitter and ability to transmit better formats (DSD is quite limited over SPDIF for example).
If your comment is addressed to me, return to post # 10 and follow the link.
 
It was a general comment, but thanks.

That's still USB and if the DAC is running in asynchronous mode and doing it's own internal clock regen... unless something is going very wrong I have my doubts that said product makes an audible difference, or at least, one more audible than something like the Schiit Wyrd, which I also find to be a dubiously useful product.

If USB is clean enough for the professionals to record the source material with... well.
 
It's less speculation and more skepticism. Comes with the profession. In a way internal reclocking at the DAC is a form of signal regeneration so we're in agreement there. I'm mostly skeptical that regenerating it twice is useful. That device is pretty much doing what the DAC is doing already, if, as I said, it's running in asynchronous mode. Reclocking is an inherent part of that process.

I wonder if any USB 2.0 or USB 3.0 capable opto-isolators are available. That'd basically knock out any noise from getting through on the signal part of the USB and could be done for $10-15 bucks.
 
What you are saying is that MUSIC DATA is special.

No, I am NOT. The data (the purely digital bit stream) is treated identically, regardless of the media being transported.

The bits are not the problem; provided your link isn't so bad that unrecoverable errors occur, the received data stream is identical to the transmitted data stream.

So, we recover the perfect digital bitstream from the bearer medium at the receiver, and use a DAC to convert to the desired analogue music signal.

The problem comes due to the fact that those bits carried over the bearer medium have an analogue representation (of the bit, or data symbol); a real, physical signal. That signal can carry extraneous analogue noise, as well as the noise inherent in the fast edges of our digital data stream (Fourier series).

Unfortunately, if we don't take care, the bearer noise signals can couple into the analogue side of our DAC, both those extraneous noise signals, and the digital edge noise. This is what we must try to eliminate when designing an interface and the DAC, and there are a number of techniques to do this.

These techniques involve the transmitter (the interface data driver, its power supply, the line impedance control/filtering), the cable (preferably a good, impedance controlled, shielded cable), the receiver (again, power supply, input impedance matching, receiver buffer, filtering), and in subsequent processing stages, using isolation of the receiver from the digital processing, then isolation of the digital processing from the DAC digital input, and an isolation barrier across the DAC, which provides the digital/analogue barrier. Get these isolation barriers right, and you should kill any input coupling to such an extent that it becomes inaudible.

Then there's time domain noise to consider, especially if the DAC is data source clocked... That's why a destination-clocked system is best (e.g the 'asynchronous' USB transfer mode); the clock can be propagate back from the DAC, to all the isolation reclocking stages. Using a FIFO buffer, we can isolate the DAC output sample timing from the source data supply.

Source-clocked transfer mechanisms require the DAC to be driven by a clock recovered from the data stream. Recovered clocks are harder to produce with low jitter than those generated by an independent clock. Jitter (time domain noise) causes audible effects in the DAC output. Like 'grittiness'.
 
Either way, it's a failing in the DAC design. Noise in the USB power/signal should be accounted for during the design process of the DAC.

When you're designing to a budget, you take shortcuts. These might be considered 'design failings'. Engineering is always a compromise...

So it's possible that a USB regenerator acts like one of the isolation stages I mentioned, reducing the amount of noise carried from source to DAC. In a DAC with poor input isolation, it will improve the audio performance.
 
When you're designing to a budget, you take shortcuts. These might be considered 'design failings'. Engineering is always a compromise...

So it's possible that a USB regenerator acts like one of the isolation stages I mentioned, reducing the amount of noise carried from source to DAC. In a DAC with poor input isolation, it will improve the audio performance.

At the price of the regenerator I'd personally rather buy a DAC that didn't need it's help. $200 is steep to correct something that shouldn't need correcting.
 
Currently an Audient pro-audio interface as I need the mic pres/phantom power. Feeding my Millett hybrid and Fostex cans primarily.

On the stereo I've mainly been doing vinyl for serious listening lately. That system is in a state of flux. Planning to grab a Topping D30 or D50 soon.

I consider the Audient to be well into the realm of diminishing returns DAC wise. I've been perfectly satisfied with it's performance.
 
Either of those would lend itself to upgrading the OPA2134/OPA1612s with Burson FET modules.

I replaced the OPA2134s/OPA2604 in a Music Hall DAC 25.3 with Burson V5s for a marked improvement in transparency.


Is that the iD14?

Thoughts on the OPA627 pair on riser boards?

Yes, iD14. Some sort of discreet Burr brown DAC chip. Running line out to the Millett through 1/4" jacks. One of the reasons I want to grab the topping unit is to do a comparison with it's pre-outs. I've always found pro-audio gear to have pretty decent performance for the price and the mic pres in the thing are gorgeous.

Cheers,
Nathan
 
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