You might want to think about building a dedicated computer server like the one described in the link. General purpose computers are ill-suited to hifi for the most part. You may get a minimal improvement from those filters, but you'll lose 24/192 streaming ability, you need HiSpeed for that.

http://www.computeraudiophile.com/content/494-computer-audiophile-pocket-server-c-p-s-v3-topangas/

How to get the lowest amount of interference in your audio system. 
This goes  for all analog as well as digital and analog and is based on asymmetry in power supplies be them SMPS (switch mode) or linear (transformer)

Remove all interlinks so you have ONLY separate equipment.
Note that equipment that is double isolated differs from those that have safety ground.
Also note that safety ground is NOT a the same as  RFI ground !
In general all safety grounds are extremely lousy RFI grounds.

You will need a voltage finder.
I use a sort-of screwdriver tester designed to show Live an Neutral.
Not the kind with a neonlight in it but this one can show voltages in a few coarse steps.
Another option is to use a multimeter.
It should have AC voltage AND AC current measurement capabilities.

Connect a mains fed audio component to mains (3 pin to 3 pin socket) and hold the tester against the RCA or other connector (the screen or common).
OR multimeter:
1 testlead to a safety ground or something you KNOW is REALLY grounded.
Other testlead of the meter to the RCA shield or other connector.
Set the meter to ACV(oltage) first and choose the highest range.
Set the meter lower when needed.
Note the voltage.
Now set the meter to AC A(mpere = current.
Same testleads on the same pins/conditions
Choose a setting of several 100mA (10A settings won’t show anything).
Go to lower settings to read a proper value.
Note that current.

Now, and this is NOT possible in certain countries, plug the mains connector in the  mains outlet but phase reversed (rotated 180 degrees).
Redo the measurements and compare the results.

Mark the lowest voltage/current setting on the mains socket and mains plug so you can always find the lowest current.

Quick and dirty method only your finger and sometimes a metal surface needed.
Plug in the single audio component and make sure it is on something isolated (plastic or something)
Now rub your finger over a metal cover or put a metal plate on top of the audiocomponent and connect that to the shield of the RCA connector with some wire.
If you ‘feel’ your fingertip (where you touch the metal) to ‘bounce/vibrate’ a bit you will know there is current leakage.
When you feel nothing the leakage is very small.
Again reverse the polarity on the mains plug (rotate the plug 180 degrees) and test again.
Note the position of the plug opposite a mark on the mains socket for the lowest ‘ripple/hum/bounce/vibration’ in the finger tips.

Note that equipment with figure- 8 mains connections also need to be marked as these can easily be set in the wrong position.

When all equipment is tested and set for lowest leakage current connect them with clean interconnects (clean the RCA’s too if dirty/oxidised) and this will be the best situation.

Those with weird sounds or plagued with  ticks from external  equipment e.t.c. or faint hum or whizzing noises may find their equipment to be totally silent.
If still plagued with unwanted signals then one can resort to ferrites (do little if nothing mostly), mains filters (may also worsen things !) or separation transformers.

Thanks for that tutorial Solderdude.
I still don't understand half of it but I'll eventually get there, lol.
I'm sure it's pretty simple.

I still don't understand half of it but I'll eventually get there, lol.
I'm sure it's pretty simple.

I 'hunt' for RFI problems professionally now and then and can assure it is very difficult 'seeing' where the troubles come from when you don't have extremely expensive RFI receivers to show you where the problems MIGHT be coming from.

In general most equipment has a higher leakage current when connected to mains.
This is because mains has a Live wire and a Neutral wire.
The Neutral wire should not have any voltages with respect to ground, the Live wire (that's why it is called live) only has a voltage on it.

Transformers leak through capacitance between primary and secondary windings.
The bigger the surface (bigger power transformers) the more capacitance the higher the leakage.
The closer the primary and secondary winding (toroid = close, E and R core is wider apart) the higher the leakage, except when a 'shield' is used between the windings.
The reason why switching L and N in a transformer helps for HUM related leakage currents (not so much for RFI) is because in one case the N wire is closer to the secondary wires where the leakage is the least as there is no voltage present. When (by switching phase) this winding is connected to the L wire there is a high voltage and thus leakage present.
This is why it is 'important' the L (brown) and N (blue) wires of a mains transformer as this should lead to lowest leakage when connected correctly.

For SMPS it is very dependent on the circuit used and filtering applied.
No real guidelines here.

When the tutorial is followed the system should be the least susceptible to garbage on the mains.

So... that IFI thing is good?