Yes. 2 weeks ago, no response. To be fair to Pavel I did not threaten to return the unit because I was able to work around the delays but did ask if he had seen the issue before and if a firmware update could fix it (or at least make the delays consistent).
I agree with this in principal but clearly there is something occurring with the nanoDIGI + Okto combination. Feels to me that it is impedance mismatch related as the transformers improve performance.
There is no such thing as a RCA plug with 75 ohm characteristic impedance. That being said I am using a RG6 cable which has a characteristic impedance of 75 ohms and a 75 ohm BNC connector. The exact cables I am using are linked below.
https://www.bhphotovideo.com/c/product/1053971-REG/kopul_vrbc_401_bnc_male_to_rca.html
The noise is a popping / crackling that occurs every few seconds. It never occurs on Okto channels 1-2 but occurs on all other channels. I've tried routing different channels from the nanoDIGI to the Okto but the results are the same, whatever is routed to channel 1-2 of the Okto is fine and the other channels have noise. That being said there is definitely some interaction with the DSP here. With everything set to flat the crackling does not occur as often as when crossovers / EQ are applied.
The nanoDIGI operates at a constant 96 kHz sample rate (ASRC on input). I do not have any other 8 channel SPDIF sources besides the nanoDIGI. As I mentioned the nanoDIGI was not intended to be my primary DSP (I prefer the SHARC as it has much more power and 3 inputs with the DIGI-FP) and am really just trying this out as an experiment.
Tonight I will try routing channels 1-4 to the Okto and channels 5-8 to other DACs, will be interesting to see what happens. Prior to this I had never used all 8 channels of the nanoDIGI, it certainly is possible that the nanoDIGI is defective.
I am very interested if anyone has successfully used 8 channels of output from a nanoDIGI with the Okto dac8 pro.
I've attached some measurements to add to the discussion. The frequency response sweep shows the difference in noise when no DSP is applied (brown) and when DSP is applied (green), both cases have 8 channels of output from the nanoDIGI. Clearly DSP has an adverse effect. I've also attached 1 kHz FFTs showing 6 channels vs 8 channels of output with no DSP applied. There is clearly a huge step change in noise when adding those 2 extra channels.
Michael
