Originally Posted by Ronnie
And lastly Dave, why MIGHT the GISO have an impact??

IMHO the Galvanic Isolation offered by the GISO could function in a similar way to Ruby Ferrite Podule described above........i.e. that it would filter out undesired RFI / EMI from entering the Sooloos Endpoint.......thereby reducing internal RFI.......thereby allowing more effective conversion to LPCM......and the main result is lower Jitter on the digital output .......and a more pleasing Musical Sound emanating from our kit

However, due to having to deal with RFI mitigation in the 'day job', I feel that the GISO (just like the Ferrite Podule and RFI filtering in the ID41) is more of a "Cure" than a "Prevention"

And as with everything else, it's better to Prevent RFI than to cure it

So, I think the previously mentioned measures to reduce RFI on the Sooloos network is something that people should look at......i.e.

a) a dedicated Switch for our Sooloos kit;

b) Shielded and Screened SSTP cable for all Sooloos transfers (even a good idea throughout the home network)

c) moving any Wifi Access points as far as possible away from our Endpoints to reduce ambient RFI

d) minimizing the use of Powerline Networking devices throughout our home networks and especially not using Powerline connections to Sooloos Endpoints [as they are known to introduce high RFI levels]

It could be then argued that these steps would leave little for the GISO to do (minimal audible benfit) and that would be correct.......but as I said, I believe Prevention to better than the Cure


Summary
Meridian have done a lot to reduce the amounts of Internal RFI within their various devices

By using the few simple steps above, we can help by not reintroducing RFI / EMI in the vicinity / environment of our Sooloos Endpoints

We can add to that by using GISO's, Ferrites and similar measures just before the Endpoint to reduce any remaining RFI entering the Sooloos Endpoint via the network cable

Hi Ronnie,

I agree with you 100% in principle and it's clear now that the GISO gets its gains simply by reducing RFI that would otherwise be passed into the ID4x and beyond.

I think your recommendations for preventative measures are bang on and I've gone a bit further than that, with an upgraded PSU on my dedicated switch and quite a hairy-arsed RF mains shunt filter (Vertex). I also have dedicated mains (much cleaner than ringmain), but I still got a very big impact from the GISO.

I'd guess that, even with very thorough efforts to minimise additional RF ingress, it's ultimately going to get in there from several sources that can't be avoided, including mains.

As you say, adding GISOs or ferrites after taking all the avoidance measures might be a good route. It's certainly worked for me. But with the new level of detail and subtlety that I'm getting with the GISO and given how easily I got it, I'm thinking I need to spend some time working out how to go further on the prevention side. In essence, I see things exactly as you do, although my gut feel is that, even in a very well-sorted system (or perhaps more so in a sorted system, due to extra resolution), the GISO may add that extra two levels of refinement that can't practically be achieved with pure prevention.

Again, it's time to experiment a bit :-)

808v5, MD600 & DSP7200.1
Dedicated audio mains supply