The J-Box has some big problems, according to the reviewer its not suitable for chassis evaluation due to high noise, which means you need more external devices like a separate AMP or Microphone.
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Joined 2003
It's noise level is acceptable, similar to what you would expect from a budget USB audio interface. You may find measurements in my review of the noise floor (white trace)
...and I produced clean impedance measurement with the device:
...and I produced clean impedance measurement with the device: