Bare boards will be $275What is the introduction-price for bare pcb without box? I am possibly interested in 4 of them.
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.
View attachment 16438
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
Unfortunately I cannot, I currently do not have access to and audio analyzer.Would you be able to post an SMPTE IMD % vs FFS/dBfs graph for comparison to Amir's, please?
Will these modifications solve the high noise floor that we see in Amir's jitter test, as well as in the lower part of the IMD vs level test?
I am referring to the lower level part, on the left-end side of the graph.The IMD issue will definitely be solved, as that is a clear result of saturation.
I am referring to the lower level part, on the left side of the graph.
After a closer review of the data, I have a very strong suspicion that the manufacturer also put some wrong value filtering capacitors on the board. This is because the noise seems way too high.
That should not be there, at low levels the IMD should be better than -60dB not anywhere near -40db where it is now.
I really should have measured the device myself before sending to Amir, but renting an audio analyzer is way too expensive for a small manufacturer like myself.
I can guarantee that every production unit will be fully tested and meet the specs.
I dont think they did it intenianally, but mistakingly. These boards were populated by hand not by pick and place, so human error is very possible.This is somewhat disconcerting, how can one be sure they get a unit that performs up to the spec if the manufacturer can change the parts without notice?
I like this idea, something for me to brood on.Maybe you can provide a test protocoll for each device when it is sold, for assurance?
Just put a paper with it within each shipping package.
My actual performance using the same settings as for DAC tests in dashboard, has less noise:Another thing to keep in mind is that the APx555 that Amir uses has it's own residual noise of 1.1uV.
Ok, but even the 0.88uV will still make a difference at lower noise levels.My actual performance using the same settings as for DAC tests in dashboard, has less noise:
View attachment 16464
Or about 0.88 uV.
If I go up to 45 kHz bandwidth, it will then get up to 1.2.
What is the noise level measured with GALA connected and receiving 0FS signal.
I assume this is not A-WeightedHere it is with S/PDIF off (relay disconnected in the analyzer):
View attachment 16465
Here it is with S/PDIF on but generator off:
View attachment 16466
Results are the same for a -150 dB test tone at 1 kHz.
It is not.I assume this is not A-Weighted