Best means of isolating digital equipment i.e. DACs, CD transports, wall warts etc.


Is it better to route these digital noise polluters through a conditioner, isolation transformer or both in series?  Is a "digital" power cord sufficient by itself or could it be used with any of the above without negative side effects?  There are a lot of anecdotal observations in many old threads.  Can anyone help clarify based on what they have found?  I'm getting ready to add a dedicated circuit for my audio system and will be reconfiguring power cable connections.
jc4659
@tomic601 I don't have the luxury of 3 dedicated circuits; I will only be able to add one.  Right now I have my analog plus ayre codex DAC plugged into a hydra 2 conditioner (clean side).  I use a distributor to gain extra outlets since the hydra only has two.  All devices which use a switching power supply are plugged into a power strip which is plugged into a MGE 250VA isolation transformer.  I am assuming this prevents noise from going back into the circuit.  Please correct me if I have this wrong.
Eric, you have to be careful with Parts Connexion. They can be a terrible rip off. They sell 14 gauge three conductor shielded power cable for $100/linear foot. But here is basically the same stuff for $3.00/linear foot
https://www.wireandcableyourway.com/belden-9367-14-awg-1-triad-shielded-300v-power-limited-tray-cabl...
You can make a wonderful shielded power cord for $45.00 and make them to fit perfectly. 
If your power is reasonably clean all you need is shielded power cord not only to keep stuff out but to keep stuff in, isolating your interconnects from the power cord. 
In reality there is no such thing as a dedicated line. It all goes back to the same panel and mains. The individual lines are sized to the circuit breakers. Very few system in their entirety are going to trip a 20 amp breaker. Adding more current capability may make you feel better but it will not improve the sound in any way. As far as noise is concerned all the stuff in the house is connected to that panel. So, see if any of it causes noise. Turn your system all the way up and turn an the AC. Stick your head in the speaker. Do you hear it? Next the refrigerator. Turn down the thermostat. Do you hear it in the speaker? What about the washing machine or the blender. If you have good components you will not hear a darn thing and if you do not hear a darn thing forget about it. You do not have a problem so stop wasting money on a problem you do not have. 
two lines are fine, i would swap the Hydra and the Transformer and see which sounds better.

on the post above, maybe...but first get your audio clean circuit off the dirty leg of the AC panel, that is the one with refrig compressor and motors.

also good to tighten your panel connections including grounds on a periodic basis - dont do any of the work i mentioned in this post if unqualified.
@jc4659 - the best way I have found to isolate components of any kind is to ensure they are NOT plugged into receptacles that are "daisy chained" together in a parallel configuration.

The daisy chained approach is often used in many power strips and power conditioners - so I avoid using them

I have one outlet providing power to my entire system...
  • connected to that outlet is an extension lead with a single dual outlet on the other end
  • into that is connected my amp and a second power distribution box
  • each outlet in the distribution box is linked via it’s own pieces of wire to common neutral and live connection points
  • that, in effect, connects each device directly back to the wall outlet
  • so it is as though each device is plugged into it’s own wall outlet

This seems to eliminate any noise pollution issue in my system.

I also use very good power cables that eliminate cable generated noise, so the background of my system is extremely quiet.

regards - Steve