anyone knows if changing the volume above 0 ( default +2dB for example) may change the sinad? It would stay flat at 125 like the last steps in the SINAD vs Volume graph?
it will be possible to compare with amirm's review a thd-n vs frequency a 48k/24 0db with your cosmos? with of course your "racing" M-T.Not by much. I'm measuring this with E1DA's APU notch + Cosmos ADC, so the result is different than Amir's as this setup has lower noise than APx555.
At -0.0dB THD+N is -127.3dB, and at +2.0dB it's -127.8, so 0.5dB better at +2dB setting.
View attachment 356565
View attachment 356566
Notch filter on APU is only at 1kHz and 10kHz, so will not work for a sweep.it will be possible to compare with amirm's review a thd-n vs frequency a 48k/24 0db with your cosmos? with of course your "racing" M-T.
;-)
i know.. but with only cosmos? ;-)
interresting... we learn about cosmos..and 555
interresting... we learn about cosmos..and 555
we need an rme now ;-)
THD rising <70Hz for the internal reason of ES9822, I didn't find a way to reduce that anyhow. About THD rising at >7kHz, this is ES9039Pro profile. You can measure 10k THD with APU and see that H3 will be about -110db, IMHO, it is a shame. BTW, ES9039Q2M has -135db of H3 at 10k test.
THD rising <70Hz for the internal reason of ES9822, I didn't find a way to reduce that anyhow. About THD rising at >7kHz, this is ES9039Pro profile. You can measure 10k THD with APU and see that H3 will be about -110db, IMHO, it is a shame. BTW, ES9039Q2M has -135db of H3 at 10k test.
As I told you, Cosmos APU has residual THD+N about -135db@1khz and 10Vrms(or 5V with +6db), roughly it is 3x times less than APx555 on a lucky day. All DACs in the range of THD+N -126-130db@1k APx555 will show as -124-125db due to it being the inherent limit of that noisy analyzer. When L7 tested Cosmos APU he tried to measure THD+N of some DAC(not sure which model but 9038Pro) which got -125db at APx555b and next with Cosmos APU->Cosmos ADC->APx500_SW, the result was -127.5db as I remember. Please note, L7 APx555b is a few years newer vs Amir's and L7 always gets a bit lower THD+N on it.
PS: Paul, I guess you (and John-REW) haven't seen my Excel sheet-tool for an ADC residual noise compensation? I intentionally set here A-weighted units to minimize the error of subtracting scalar noise values by narrowing of BW(A-curve is about 100-12500Hz where a noise floor is always flat). And it works not too bad, for instance, Meizu HiFi DAC with bare Cosmos ADC shows SNR -122db(A), after Excel sheet compensation -128db(A), and with APU -130.5db(A). You can subtract noise vectors (bin by bin) and don't care too much if the noise floor isn't flat. Due to the THD+N combo being limited by the N component in most cases, you may compensate for the APU+ADC residual noise and move -135db limit even deeper. The same thing is possible for APx500 but seems AP also haven't seen my Excel sheet
Paul, I gave you already all that you need - the idea Excel sheet works but you have a chance to implement that better as a bin minus bin subtraction.
Paul, I gave you already all that you need - the idea Excel sheet works but you have a chance to implement that better as a bin minus bin subtraction.
i.e. if imagine that aliens give you an ideal analyzer, the DAC rather has THD+N <-129db@1k, unlike AP showing that, and all other top DACs, as -124db