ive been experimenting with measuring the line-in of the d:vice, particularly to determine extent of jitter over its synchronous connection to the iphone
this is using a basic minijack to 2x microdot cable with resistors between signal and ground to 'trick' the d:vice into 'seeing the mics' and turning on
i did not install blocking caps in this cable as the schoeps CMRs i intended to use with it already have blocking caps to take the bias power out
The results are.... not so great.
log scale:
linear:
someone who knows better than i do described that graph as 'The DPA clearly shows evidence of clock jitter. The widening of the skirt on either side of the tone shows jitter with random low-frequency phase noise."
not sure if it would be better if i used blocking caps, or if that noise is a result of bias voltage and relatively independent of any jitter. Technically, the sharp jitter spikes are mostly below -100 dB and likely inaudible in our normal usage. but the distorting of that curve starting at -80dB is unnerving
for reference, heres what a PCM-A10 looks like with same 10k tone in a jitter test
note that with actual microphones i cant measure anything different between these two different recorders, and its very possible that the poor d:vice measurements are a result of the mic power. maybe ill try the A10 with PIP on and see if it gives similar problems in measurement
