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DAC's : The missing feature: Signal quality

One thing I wish DAC's would provide is some idea of how much jitter and noise a particular input provides. This is something which I think with a little work could be gleaned from the input circuits.

I want something that tells me "woah, that's a really dirty signal coming in, but i"ll do the best I can with it."

One common source of noise is ground loops. Another may be high jitter from a source like Apple TV. This would also help us evaluate the benefits (if any) of various signal cleaners and reclockers.

Best,
E
erik_squires
roberjerman
4,319 posts
 
Even the first-generation CD players had jitter levels below 1 nanosecond! What they didn't have (in the first year or two) was full 16-bit capability. Typically 14-15 bits, due to DAC-chip (ladder-type) architecture. This only reduced noise-floor and dynamic range by about 10db! Still far better than any tape/vinyl playback! L-R separation for stereo imaging was unaffected - again far better than any tape/vinyl system! Ditto for harmonic/IM distortion! 
erik_squires OP
16,185 posts
 
If you are going to interject your own agenda without actually addressing the original post it is considered polite to start your own thread.
mzkmxcv
777 posts
 
The reason this is not common as it’s not really needed. It’s cool for curiosity or scientific purposes (instead of having to buy an analyzation tool/software), but no real benefit for consumers. As doing a J-Test (extreme jitter, more than you’d likely ever have), even cheap DACs can reduce down to at least -100dBFS, better than the noise floor of a CD, and since almost no content is gonna have sounds meant to be heard below say 40dB, even a cheap DAC would have no jitter when playing 40dB to 140dB.
celander's avatar
celander
1,503 posts
 
Erik, if I correctly understand your desires for signal quality detection at DAC inputs, then I suspect it would be an extremely costly DAC having that attribute. It would likely be on par of an external reclocking device cost. I’m not sure you want to spend that kind of $$$ for a feature that is nothing more than an idiot light.  
erik_squires OP
16,185 posts
 
The reason this is not common as it’s not really needed.

No one has any idea if this is needed or not because end users never get to measure it themselves. The argument here is really that unless it's blatantly obvious to the ear we should not care. To those people I ask: Do you even buy high end equipment?

I've read a number of reviews, and experienced enough variance in performance of sources to know that this is not the case. Having some sort of Green/yellow/red indicator about signal quality and noise I think would be helpful. For instance, there are a number of reclockers and signal cleaners on the market. Wouldn't it be nice if our DACs could indicate directly if a particular source might benefit from it?

Like, green on CD player, green on streamer, but woah, that AppleTV signal is a mess.

So pick your place. Bits are bits and unless the signal drops out I don't care, or I care about signal quality and would like to know if I'm missing something important.
Best,
E
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