I recently bought a Tripp Lite IS250 250W Isolation Transformer, to add into my system, which is as follows: PC -> optical cable -> DAC1 -> Lyr -> (headphone out) HE-6; (rear rca out) KRK subwoofer -> KRK rokit 8 monitors Before adding the Tripp Lite, I had a very noticeable noise floor in my KRK speakers even with no audio playing. I added the tripp lite, plugging only the DAC1 and Lyr into it; leaving the speakers and computer all still on surge protector / power strips on the wall outlet. Since adding the tripp lite, the KRKs are dead silent, no noise floor at all. I suppose the Lyr, being a powerful and very sensitive amplifier, was not doing too well with "unclean" power or some voodoo thing that I don't understand, and the Tripp Lite fixed that issue and the Lyr is getting "clean" stuff now and not putting out a noise floor to the KRKs. I do live in a 70s apartment, so maybe the power from the wall is pretty "crappy." That I can accept, but what about this: I previously did not notice much of a noise floor listening to music through my HE-6 headphones -- these come straight out of the front of the Lyr, unlike the KRKs which are plugged into different things and have power supplies of their own, etc, etc. However -- and this is where I think I am probably imagining things -- I feel like my headphones are clearer now than they were before, now that the Lyr/DAC1 are lugged into the isolation transformer and not a plain surge protector. It is as though tings are cleaner - if there was any static background noise in the headphones before, it is further reduced now, I just can't be sure of it because it seems subtle or something. Well - subtle -- that's the thing, I haven't done a scientific back and forth blind test yet, but it seemed like a big difference to me, I "noticed" the new clarity (or imagined it, your choice) right away as soon as I first tried the headphones after installing the isolation transformer. Any thoughts? edit: Also, I might add that this transformer is extremely, extremely heavy for it's size. It's like a solid brick of iron or something. It is very cool and I like it. And, though the amazon.com image was of a white metal box; mine is sleek black.