Shielding components from EMI/RFI... Help please

Thanks, Sarcher. Interested to hear if the Cat6 makes any difference.

I have an update...

I have installed 7 copper plates inside my preamp/dac. They are each 16 gauge, or .06", which is fairly thick. I grounded each plate to the chassis. I bolted 3 plates around the analog output stage, 3 plates around the power supply, and 1 large plate to the underside of the lid.

The results are surprisingly good. The noise floor dropped noticeably. The resolution increased slightly. The high frequencies got smoother. I can turn the volume up about 3dB with the same comfort level.

I've tried quite a few tweaks and mods, and this is one of the most audible. The results are much more obvious than when I recently added ERS cloth to the preamp/dac. Total cost for this mod: about $100 in copper from an online retailer, who also cut the plates to exact sizes.

Next up: I'm building a copper/aluminum enclosure for my reclocker. The enclosure will be grounded to a dedicated ground rod I just buried under the house...

...to be continued.

Bryon

I installed my shielded cat6 today. I think it made a slight improvement but it could just be my imagination. I had to reboot my NAS and Linn DS afterward. It takes a long time for the NAS to reboot so it makes it difficult to do a proper A/B comparison. It looks like the Linn DS ethernet port has metal tabs on the sides so I think it is shielded. I don't know if they connected the port to ground though. My NAS also seems to have a shielded port. The only thing in the chain without shielded ports is the router. So I plugged in both ethernet cords next to each other and then wedged in a scew between the metal shields on the RJ45 plugs to tie their shields together. Does anybody think that will work?

The only thing in the chain without shielded ports is the router. So I plugged in both ethernet cords next to each other and then wedged in a scew between the metal shields on the RJ45 plugs to tie their shields together. Does anybody think that will work?

I doubt that is necessary. As long as the shields are grounded at one end, I would think that should be sufficient. And I would expect that which end is grounded doesn't matter, since what you are trying to do is to prevent rfi from escaping from the cable.

In other situations, as you may realize, if the signal flow is unidirectional and only one end of the cable shield is grounded it is generally desirable for that to be the source end, so that rfi that may be picked up won't be conducted to the destination component. But that is not applicable in this situation, because rfi pickup is not the concern (and probably also because the link is bidirectional).

Regards,
-- Al

Almarg, I have heard of interconnects with the shield only connected on one end. I was not sure if that arrangement would work in this application.

Thanks again.

Sean

Sounds like the Cat6 experiment has produced uncertain results. I've already ordered shielded Cat6 from Amazon, so when it arrives I will let you know if I hear any difference. In the meantime...

I can now report that my shielding experiment has produced fantastic results. I hesitate to use the word 'fantastic,' because I don't want to diminish my credibility by overstating the facts. But the fact is that the addition of shielding has produced very impressive results.

I had an audiophile friend over who is familiar with my system and he said "It sounds like a different system." THAT might be an overstatement, but it is fair to say that the system sounds MUCH improved. Two improvements are particularly noticeable: Greater resolution and less high frequency grain and glare. The difference in these two categories is so pronounced that you can literally hear the improvements from the next room.

Here's everything I've done so far:

-Custom cut 16ga. copper plates around the Meridian G68's power supply, analog output stage, and the entire underside of the lid. All plates are grounded to the chassis.

-An aluminum/copper enclosure around the Empirical Audio reclocker. The enclosure is grounded to a dedicated ground rod under the house, and the reclocker is electrically insulated from the enclosure.

-An aluminum/copper enclosure around the Sonos. The enclosure is grounded to the dedicated ground rod, and the Sonos is electrically insulated from the enclosure.

The biggest gains were achieved by adding copper plates inside the Meridian preamp/processor. I added plates in three separate stages, and each time there was a clearly audible improvement. Apparently, in this case, more is more.

I don't know how generalizable my results are to other preamps, because my Meridian G68 is undoubtably much noisier than the typical audiophile preamp. But my G68 is also my dac, and I suspect that similar results could be achieved with other dac's or players.

It bears repeating that I am not an ideologue when it comes to shielding, as you can see in this thread. My (admittedly limited) experiences have led me to prefer unshielded or minimally shielded analog interconnects and power cords.

But digital interconnects and digital circuits are another story. For a while I've suspected that shielding most (all?) things digital is a good idea, and the results of this experiment confirm that suspicion. Of course this is a sample size of 1, so I recognize that YMMV.

Bryon