restorer-john
Grand Contributor
S/N isn't Dynamic Range either.
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Review and Measurements of Orchard Audio Gala DAC
- Thread starter amirm
- Start date
+1. Claimed specs seem to be more or less in line with the discovered. The price of $500 for the feature set makes me shrug though. I suppose big mark ups is how boutique shops stay in business.
Last edited:
The noise stays under 1uV pm on the first chart. The spikes are harmonics.
restorer-john
Grand Contributor
There appears to be considerable confusion as to the actual definitions of S/N, SINAD, THD, THD+N and Dynamic Range. They are not all the same and although related, they are in no way interchangeable.
S/N and DR should be very close for most if not all practical purposes: https://www.ap.com/technical-library/more-about-signal-to-noise-ratio-and-dynamic-range/
restorer-john
Grand Contributor
The other big issue is this:
Amir writes "higher better".
When each product has a completely different output level, they simply cannot be compared to one another in a ranking such as this.
It's like comparing SINAD results for 10watt per channel amplifiers with 500watt per channel amplifier. Even with exactly the same overall noise level, the 500w/ch amplifier gets a 17dB headstart in S/N numbers and will end up at the top of the chart and yet they both are just as noisy in real terms.
Amir writes "higher better".
When each product has a completely different output level, they simply cannot be compared to one another in a ranking such as this.
It's like comparing SINAD results for 10watt per channel amplifiers with 500watt per channel amplifier. Even with exactly the same overall noise level, the 500w/ch amplifier gets a 17dB headstart in S/N numbers and will end up at the top of the chart and yet they both are just as noisy in real terms.
TimW
Major Contributor
I will admit that I am confused. You compared Amir's SINAD measurement to the SNR spec of the Gala. Amir compared his SINAD measurement to the THD+N spec of the Gala. Confusing
restorer-john
Grand Contributor
It doesn't help that prior to the widespread usage of FFT/Spectrum analysers, pretty much all distortion metering equipment was really measuring THD+N and calling it THD.
My old analog Leader LDM-171 can't separate the residual noise from the harmonics and ultimately gives a total of everything and calls it 'distortion'. I really only use it for an analog ACmV meter these days, but for fast, spot readings (down to -80dB), it can't be beat.
Noise is defined as 'unwanted signal' IMO and that means everything other than the desired signal, including harmonics as they are ultimately the limiting factor aren't they?
You can call it correlated or uncorrelated, but it doesn't matter- it is an unwanted signal at the end of the day.
Traditional S/N measurements called for the signal to be shut off and the residual measured. Most D/A chips mute after x samples at zero so the -60dB figure is used I think in Amir's unit and notched out. I can't measure that low (-100dB) reliably with my gear, maybe soon I will be able to.
My old analog Leader LDM-171 can't separate the residual noise from the harmonics and ultimately gives a total of everything and calls it 'distortion'. I really only use it for an analog ACmV meter these days, but for fast, spot readings (down to -80dB), it can't be beat.
Noise is defined as 'unwanted signal' IMO and that means everything other than the desired signal, including harmonics as they are ultimately the limiting factor aren't they?
You can call it correlated or uncorrelated, but it doesn't matter- it is an unwanted signal at the end of the day.
Traditional S/N measurements called for the signal to be shut off and the residual measured. Most D/A chips mute after x samples at zero so the -60dB figure is used I think in Amir's unit and notched out. I can't measure that low (-100dB) reliably with my gear, maybe soon I will be able to.
Last edited:
- Joined
- Feb 27, 2018
- Messages
- 522
- Likes
- 668
THD+N is the reciprocal of SINAD, thus making them interchangeable with each other.
restorer-john
Grand Contributor
Divide the SINAD number by 20. Inverse Log that number and 1/x gives you the distortion. x100 for percentage. Why we need them both on the dashboard, I don't know.
- Joined
- Feb 27, 2018
- Messages
- 522
- Likes
- 668
I think you can choose what to show on the dashboard and they're what Amir prefers to use since the beginning. I could be wrong though.
restorer-john
Grand Contributor
There's so much on the AP he could show it's ridiculous. I understand the overload that too much information can impart, but the channel balance in dB as opposed to absolute voltage levels could be more useful to many.
With measurements, some will want more, some less and some will want measurements that others don't care about. You can't please all the people, all the time, especially measurement junkies like us.
It would be nice if @amirm could write on this forum a short definition of these concepts, and exactly how they correlate.
I am myself a little bit confused about how they all correlate.
Also an explanation of all the graphs used in reviews would be helpful. What to look for, what is important, etc.
For example, the intermodulation distortion graph shown here. Too me, the Gala vs e.g Topping DX7s is just good at different levels. I see no clear winner. What makes the Gala much worse than DX7s regarding intermodulation distortion?
I am myself a little bit confused about how they all correlate.
Also an explanation of all the graphs used in reviews would be helpful. What to look for, what is important, etc.
For example, the intermodulation distortion graph shown here. Too me, the Gala vs e.g Topping DX7s is just good at different levels. I see no clear winner. What makes the Gala much worse than DX7s regarding intermodulation distortion?
Last edited:
I think that established levels of audibility of various measurements could be a yardstick for selection of gear. Those who need better to salve there doubts could aim(spend?) higher. This could be part of the test result conclusions, e.g. meet that or exceed it.
By all means!
But I wander how many times this has to be repeated before becoming a reality..
- Joined
- Feb 13, 2018
- Messages
- 574
- Likes
- 720
I hope orchardaudio will not throw in the towel on that DAC as it shows very promising results, eg IMD in the -15dB to -35dB range, or the high DNR.
Let's hope the problems Amir was able to disclose can be fixed before production.
Let's hope the problems Amir was able to disclose can be fixed before production.
The more I look at the Gala dac measurements, the more I like them.
For my application, it beats the humpy ESS mobile dacs, because I will use my dacs mostly below -15dB level (due to digital active crossover and volume control).
I hope Orchard Audio can lower the price a bit to a more competetive level. In that case I am in for buying 4 bare pcb:s of them. Otherwise the WesionTEK Khadas Tone Board Dac will probably be my choice at $99 for stellar performance
For my application, it beats the humpy ESS mobile dacs, because I will use my dacs mostly below -15dB level (due to digital active crossover and volume control).
I hope Orchard Audio can lower the price a bit to a more competetive level. In that case I am in for buying 4 bare pcb:s of them. Otherwise the WesionTEK Khadas Tone Board Dac will probably be my choice at $99 for stellar performance
Hello,
Dynamic Range and SNR is not the same thing as many of you point out, also Amir does not use A-Weighing which would further improve the result. So my 130dB SNR (0 dBFS, A-Weighted, 10Hz - 22kHz bandwidth) spec is accurate, and I stand by it.
Another thing to keep in mind is that the APx555 that Amir uses has it's own residual noise of 1.1uV. This noise is present in all of the unit's measurements. This becomes more and more critical as a DACs noise gets lower and lower.
For example if you have a DAC with a noise of 1.1uV the unit will actually measure a noise of sqrt(1.1^2 + 1.1^2) = 1.56uV that is 1.41 times higher than the actual noise of the DAC.
But if you have a DAC with a noise of 10uV the unit will actually measure a noise of sqrt(10^2 + 1.1^2) = 10.06uV, almost no difference.
As for the SINAD measurement, I went back and double checked what the manufacturer did on the unit that I shipped to AMIR, and they used an old bill of material, which means the power supply for the negative rail of the op amps is not sufficient and will cause them to slightly clip or saturate as AMIR put it. That is why the SINAD measurement is lower, when I measured a different unit with the correct power supply I got -110dB for THD+N. Here is the plot. As you can see THD+N at 0 dBFS is essentially 0.0003% which would equate to -110dB.
The final unit will have the LED's significantly dimmed as well. Actually I was planning on removing 2 of the 3 and dimming the remaining one, just so that there is some indication that the unit is running. (I would like some more feedback on this as well)
In summary the specs that I have for the unit will be correct for the final product.
Another thing is that if sign up for the mailing list here, you will be able to purchase one at $349:
https://www.indiegogo.com/projects/gala-ultra-high-performance-stereo-dac/coming_soon/x/19247162
Dynamic Range and SNR is not the same thing as many of you point out, also Amir does not use A-Weighing which would further improve the result. So my 130dB SNR (0 dBFS, A-Weighted, 10Hz - 22kHz bandwidth) spec is accurate, and I stand by it.
Another thing to keep in mind is that the APx555 that Amir uses has it's own residual noise of 1.1uV. This noise is present in all of the unit's measurements. This becomes more and more critical as a DACs noise gets lower and lower.
For example if you have a DAC with a noise of 1.1uV the unit will actually measure a noise of sqrt(1.1^2 + 1.1^2) = 1.56uV that is 1.41 times higher than the actual noise of the DAC.
But if you have a DAC with a noise of 10uV the unit will actually measure a noise of sqrt(10^2 + 1.1^2) = 10.06uV, almost no difference.
As for the SINAD measurement, I went back and double checked what the manufacturer did on the unit that I shipped to AMIR, and they used an old bill of material, which means the power supply for the negative rail of the op amps is not sufficient and will cause them to slightly clip or saturate as AMIR put it. That is why the SINAD measurement is lower, when I measured a different unit with the correct power supply I got -110dB for THD+N. Here is the plot. As you can see THD+N at 0 dBFS is essentially 0.0003% which would equate to -110dB.
The final unit will have the LED's significantly dimmed as well. Actually I was planning on removing 2 of the 3 and dimming the remaining one, just so that there is some indication that the unit is running. (I would like some more feedback on this as well)
In summary the specs that I have for the unit will be correct for the final product.
Another thing is that if sign up for the mailing list here, you will be able to purchase one at $349:
https://www.indiegogo.com/projects/gala-ultra-high-performance-stereo-dac/coming_soon/x/19247162
Last edited:
This is a very good way to use this DAC with USB:
https://www.amazon.com/Nobsound-Coa...&qid=1538732522&sr=8-15&keywords=usb+to+spdif
Last edited:
Similar threads
- Poll
