New launch - SPDIF iPurifier

[MicJames]

Fascinating results. Thank you for posting.

 

In another thread (perhaps another forum, even) someone from ifi said that the spdif ipurifier would be redundant when used to feed a DAC that employs a PPL for jitter suppression. These results show otherwise, do they not?

 

The author of that post also stated that the ipurifier would be benificial when used with a DAC that employs ASRC for jitter suppression. Could you elaborate on why that is? It does jibe with what I've read about jitter becoming "embedded" in the data with ASRC, but have never quite understood how that works.

 

Thanks for all the info!

[MicJames]

I was mistaken--the post I was referring to is earlier in THIS thread, and states that DACs employing a SECOND ppl after the receiver chip will not benifit from the spdif ipurifier. I gather, then, that the 1st two DACs tested above do not employ that second PPL?

[MicJames]

Wow, thanks for the detailed explanation. That makes sense (in a general way, as I'm unfamiliar with details of digital audio processing), and also corresponds with what I found in a very limited experiment yesterday. I purchased an spdif iPurifier, and much prefer the sound I hear from it feeding a Lampizator L4/G4 than I do from the stand-alone ASCR jitter-reducer that I already owned feeding the same DAC.

 

The experiment I ran was placing the two jitter reducers in a daisy-chain to see if the ASCR up-sampling from 44.1khz to 96khz sounded better through the iPurifier into the DAC than simply redbook resolution through the iPurifier alone. What I think I've discovered so far (more listening tonight and over the weekend in store) is that putting the iPurifier in front of the ASCR sounded better than putting the iPurifier between the ASCR and the DAC. This seems to correspond with the theory you outlined above, i.e., sending a cleaned-up almost jitter-free signal into an ASCR should greatly reduce the jitter that would otherwise become re-encoded in the output data.

 

I'm secretly hoping I prefer the two in some combination to just the iPurifier alone, so I don't feel I wasted 4 times the money on the stand-alone ASCR/jitter reducer. Of course, maybe the ultimate solution is one iPurifier in front of the ASCR and one also in front of at the DAC, so that I get to spend more money. Ha!

 

BTW, I've always read that a benefit of upsampling before the DAC is to bypass a potentially more damaging digital filter inside the DAC. Could upsampling through the stand-alone ASCR/jitter-reducer in theory improve the sound, or is this just wishful thinking on my part?

 

Thanks again for all the info, and for a great, affordable product.