Topping D10s + E1DA Cosmos ADC as a measuring system

[pavlo_y0l0s]

For comparison here is attached loopback screenshot for QuantAsylum QA403 Audio Analyzer

 

[staticV3]

It took me a little bit of time to figure out how to get both of them selected in REW preferences. Just installed FlexASIO and selected that as ASIO device.

No need to mess around with FlexASIO in recent versions of 64bit REW.

Simply use the Java driver type and select the "EXCL" versions of your DAC and ADC devices for easy, stable, bit-perfect I/O.

I am getting 0.00017% THD+N and 0.000046% THD.

Highly recommended to switch to dB in the RTA Window->Distortion settings.

 

[pavlo_y0l0s]

Here is the result in dB

 

[pavlo_y0l0s]

So how would I go about making attenuator?
I have amplifier that has gain of 20x.
Should I just build resistor divider that attenuates 20x down?
For example I have calculated that I can use 220R resistor to ground and 4.18K resistor in series.
Or another combo 100R and 1.9K.
How about balanced inputs of cosmos ADC? Should I just use "+" signal and ground "-" signal?
Thank you!

 

[pavlo_y0l0s]

Another question - how did you measure 10khz and 20khz THD?
My measurement input cuts everything more then 20khz.
Image attached

 

[IVX]

pavlo_y0l0s, set the sampling freq higher, 96k or 192k, 768k. BTW, please don't crop the REW window, let us see all FFT parameters.