[sajunky]

And so far, whatever is happening in Os0 mode I'm really liking it! Think it's my favorite setting so far. NOS mode sounds good but my initial impressions are that it has a "gritty" aspect to the treble. Not sure how or why I'm hearing that or if I'm imagining it lol. But Os0 smooths things out nicely, and I also think I'm hearing a deeper soundstage with more defined imaging.

It means Fred is right. Any attempt to correct theoretical 3dB drop at 20kHz destroys phase coherency of treble or a timing, depends what filter is used.

A mode that sounds more silmilar to your R2R-11 is a real NOS. That's for sure. I only have R2R-11, can't compare.

 

[johnnycoax]

It means Fred is right. Any attempt to correct theoretical 3dB drop at 20kHz destroys phase coherency of treble or a timing, depends what filter is used.

A mode that sounds more silmilar to your R2R-11 is a real NOS. That's for sure. I only have R2R-11, can't compare.

I'm learning a lot in this thread. Wow R2R-11 really is a great deal even if you don't use the amp portion. Need to spend more time with the R-1 but so far it definitely feels like the natural upgrade from the R2R11

 

[svmusa]

Yeah, I think I'm gonna stick with Os0 for week or so before I experiment with other settings. I just got the dac today and it's too hard to gauge the differences because I haven't really gotten used to the sound enough to distinguish subtle differences. But that is interesting that you share the same experience, I'm curious how the recent R1/R28NOS versions sound compared to just engaging NOS mode on the older versions of the dacs. Like if theyre identical sounding of if audio-gd made some changes...

The differences are very subtle, but I can hear a bit smoother treble on OS 8 via headphones.

 

[FredA]

It means Fred is right. Any attempt to correct theoretical 3dB drop at 20kHz destroys phase coherency of treble or a timing, depends what filter is used.

A mode that sounds more silmilar to your R2R-11 is a real NOS. That's for sure. I only have R2R-11, can't compare.

Yes indeed. I just did the maths again. No processing is a 3db attenuation at 20khz. Was a bit tough, i had to remember the basics. Getting old.

Same story with the r1-nos. You can't get a flat response within 0.5dB without processing. Nor a 110S/N ratio playing 16-bit files.

 

[johnnycoax]

Yes indeed. I just did the maths again. No processing is a 3db attenuation at 20khz. Was a bit tough, i had to remember the basics. Getting old.

Same story with the r1-nos. You can't get a flat response within 0.5dB without processing. Nor a 110S/N ratio playing 16-bit files.

Some of that technical talk is going over my head ha ha. So just to reiterate. Os0 is ACTUALLY zero processing of any kind? It's like a"true" nos mode? Whatever is going on it's sounds fantastic and I guess that's what really matters lol. Thanks

 

[FredA]

Some of that technical talk is going over my head ha ha. So just to reiterate. Os0 is ACTUALLY zero processing of any kind? It's like a"true" nos mode? Whatever is good on it's sounds fantastic and I guess that's what really matters lol. Thanks

Yeah, it probably is.

 

[sajunky]

Yes indeed. I just did the maths again. No processing is a 3db attenuation at 20khz. Was a bit tough, i had to remember the basics. Getting old.

It is in theory, confirmed when measured with frequency analyser.

For our ears is also true if the amp is bandwith limited to 20kHz. There is a school that mandate filtering anything above Nyquist frequency and also compensate such 3dB drop to look properly on the FFT, this is wrong!

Interesting is a fact that when bandwith of the amplifier plus HP's include a first mirror image, we don't perceive a high frequency drop. In practice it is sufficient if a downstream gear has distortion-free bandwith 100kHz then harmonics of base tones are strong and coherent. This is a beauty of NOS, there is no digital glare.

It is a fact, our sensors are not analogue, but digital. My theory is that our sensors are stimulated by a mirror image, increasing sensitivity. It is why there is no perceived drop, confirmed by many. We can even go further and claim that our brain can switch entirely to a digital decoding, bypassing dual conversion from digital to analogue (DAC with complete analogue reconstruction), then to digital (by sensors), a native format of our neural network. It also explain why NOS is less fatiguing (less processing) and there is a time adopting to the NOS sound.

 

[FredA]

It is in theory, confirmed when measured with frequency analyser.

For our ears is also true if the amp is bandwith limited to 20kHz. There is a school that mandate filtering anything above Nyquist frequency and also compensate such 3dB drop to look properly on the FFT, this is wrong!

Interesting is a fact that when bandwith of the amplifier plus HP's include a first mirror image, we don't perceive a high frequency drop. In practice it is sufficient if a downstream gear has distortion-free bandwith 100kHz then harmonics of base tones are strong and coherent. This is a beauty of NOS, there is no digital glare.

It is a fact, our sensors are not analogue, but digital. My theory is that our sensors are stimulated by a mirror image, increasing sensitivity. It is why there is no perceived drop, confirmed by many. We can even go further and claim that our brain can switch entirely to a digital decoding, bypassing dual conversion from digital to analogue (DAC with complete analogue reconstruction), then to digital (by sensors), a native format of our neural network. It also explain why NOS is less fatiguing (less processing) and there is a time adopting to the NOS sound.

Interesting stuff.

I think that when you get rid of the high-freq noise disturbing the dac's performance, especially in Os8 mode, the glare is also almost inexistant. I think there is nothing especially wrong with overampling, it's just that playing at a high-frequency requires better isolation from the noisy AC circuit. Lots of high-freq noise with most devices/appliances using SMPS. Including those stupid LED light bulbs programmed to failed after X thousand hours.

I am sure you would agree hearing how analog my setup is. The audiophile switch really made big difference. For it to work, you also need a silent streamer. And isolators and so on.

An issue with Os8 is that perhaps the FPGA becomes noisier working in that mode, i don't know...

 

[OCC7N]

Question for R28 owners. How hot does it get?
-bottom/top plate

I want this thing now! - the older DA boards got me interested.

 

[sajunky]

Interesting stuff.

I think that when you get rid of the high-freq noise disturbing the dac's performance, especially in Os8 mode, the glare is also almost inexistant. I think there is nothing especially wrong with overampling, it's just that playing at a high-frequency requires better isolation from the noisy AC circuit. Lots of high-freq noise with most devices/appliances using SMPS. Including those stupid LED light bulbs programmed to failed after X thousand hours.

I am sure you would agree hearing how analog my setup is. The audiophile switch really made big difference. For it to work, you also need a silent streamer. And isolators and so on.

An issue with Os8 is that perhaps the FPGA becomes noisier working in that mode, i don't know...

I agree that oversampling removes glare. The biggest problem with oversampling is with guessing samples. There are not real values, but calculated according to some mathematical algorithm. Theoretical full reconstruction is impossible using Fast Fourier Transform (FFT). It means sound is always modified. It may have positive effect on some recording material, different on other. It is reduced in recording studios by aligning their production to the most popular DAC chip technology. It also promote shift to the computer generated music, as there is no way to evaluate authenticity of the sound, just take it as is... you like or not... the only criterion. And timing is critical, mandatory 120 beats per second. LOL. Older recordings do not sound well. The other negative is that oversampling reduce reverbations on a decay, especially when noise shaping is used - removed together with noise.

Your comments on HF noise is valid, but not limited to oversampling. It is also valid when playing a true high sampling rate content. Noise changes accuracy of sampling. A higher sample rate, higher percentage of time error, so a bigger jitter. Kingwa made it clear when writing on the Web page for R-1/R-28 NOS models. He says that NOS is optimised for jitter.

 

[FredA]

I agree that oversampling removes glare. The biggest problem with oversampling is with guessing samples. There are not real values, but calculated according to some mathematical algorithm. Theoretical full reconstruction is impossible using Fast Fourier Transform (FFT). It means sound is always modified. It may have positive effect on some recording material, different on other. It is reduced in recording studios by aligning their production to the most popular DAC chip technology. It also promote shift to the computer generated music, as there is no way to evaluate authenticity of the sound, just take it as is... you like or not... the only criterion. And timing is critical, mandatory 120 beats per second. LOL. Older recordings do not sound well. The other negative is that oversampling reduce reverbations on a decay, especially when noise shaping is used - removed together with noise.

Your comments on HF noise is valid, but not limited to oversampling. It is also valid when playing a true high sampling rate content. Noise changes accuracy of sampling. A higher sample rate, higher percentage of time error, so a bigger jitter. Kingwa made it clear when writing on the Web page for R-1/R-28 NOS models. He says that NOS is optimised for jitter.

Seems easier to have NOS sound right. I really enjoy dedicated NOS DAC more than the NOS mode of a dac that does both. I slightly prefer OS in this case.

NOS in its purest form will exhibit quantization errors. Which are random, so spreads in the whole freq range. So you need to apply a filter prior to conversion if you want to address this but then you leave the rate intact. Oversampling can result into a more synthetic sound since more operations are needed. The OS algorithm is very important and requires much processing power. I like how OS has evolved. For instance, i am surprised how good Volumio is when using the OS max quality settings.

 

[pjholst]

Question for R28 owners. How hot does it get?
-bottom/top plate

I want this thing now! - the older DA boards got me interested.

The top gets warm with time, but mine has never been too hot to touch. I’ve never checked the bottom. I feel like there is good room and venting around the amp section. I have mine on a wire rack for now, so it has room to breathe.

 

[pjholst]

On the topic of oversampling, I'm trying to think of another DAC that lets you adjust the oversampling rate. I assume this is something you would only do on a R2R DAC (doesn't make sense for Delta Sigma). Anyone think of another DAC where oversampling is adjustable? Or is that unique to Audio-GD? Personally, I think it is a really neat feature.

 

[matthia]

I want this thing now! - the older DA boards got me interested.

I am curious, what do you think does the DA-8 better than the DA-7?
Thx

 

[OCC7N]

I am curious, what do you think does the DA-8 better than the DA-7?
Thx

Nothing. Have no clue. I just collect the ones I find interesting