DIY soundcard intended for measuring amplifiers

[gpapag]

I expect knowledgeable members to chime in, rate and comment on those numbers and figures.
🙂
George

 

[1audio]

Are the Jtest measurements loopback? With a common clock some of the jitter will be suppressed. This will help interpret the jitter: https://www.bramjacobse.nl/wordpres...21/04/TN-118_Measuring_Jitter_with_J-Test.pdf The spectra don't show the 250 Hz stuff. Maybe a digital loopback will show better what a jitter free display would look like. Usually on the 16 bit stuff there is a pattern at 250 Hz intervals:

 

[gpapag]

Maybe a digital loopback will show better what a jitter free display would look like.

This proved to be a wise suggestion. Thank you Demian 🙂
From REW I recorded on file the J-test signal (120sec) on 6 sampling rates.
From Audacity I exported the FFT of its file (65536 points, Rectangular window) in .txt files.
With Excel I made the diagrams of the FFTs (attached)

The .wav files can be downloaded from Dropbox. there will bethere for 10 days

https://www.dropbox.com/scl/fi/gdld...ey=8cixv3hwhylmll8ttmm9f3ifn&st=i4w0qf2e&dl=0

https://www.dropbox.com/scl/fi/x4kb...ey=z6ws56z07kqreropjgvezbomk&st=hnfnd2r3&dl=0

https://www.dropbox.com/scl/fi/yajl...ey=z3zbbl4qcpo5qd1rommh5hzrt&st=4vrm4279&dl=0

https://www.dropbox.com/scl/fi/p9ja...ey=gln8wwb63ejbzbypdrzo1f4l3&st=mb8ysqnf&dl=0

https://www.dropbox.com/scl/fi/q6zt...ey=nyvbaio8qnknr532vvm625oyx&st=h34zbz7z&dl=0

https://www.dropbox.com/scl/fi/vzrd...ey=ltb0p4syvpjf4ya6by4lhqw7m&st=d86bkz7y&dl=0

George

 

[gpapag]

Are the Jtest measurements loopback? With a common clock some of the jitter will be suppressed.

Yes. Those were loopback (same card's DAC and ADC).

Here I use two sound cards
First attachment is EMU 0404 as the DAC and Kostas V2 as the ADC
Second attachment is Kostas V2 as the DAC and EMU 0404 as the AVC
44k1/16