Differences between various Quantum devices

David,

I have the PurePower APS 2000. Plugging in the PP2000 into the QX4 lowered the noise floor significantly in my system. Cleanliness, clarity, and most sonic characteristics improved at a level of a component upgrade. To get the most out of the QX4, you will need to upgrade its power chord (I use the Elrod Statement.) and optimize its placement within your system set-up; I have mine sitting on top of the CD player.

John

That's good to know John. I rate Pure Power very highly, so it's nice to know you found a clear improvement with the QX4.
Do you pass the mains through the QX4 to the APS 2000. I know that is the way you are supposed to do it, but I spoke to a Nordost rep at the UK national show last year. He suggested passing a cord from your conditioner to the QX4, then into a low draw piece of electronics, such as a pre amp or CD player. This avoids any risk of exceeding the current available through the QX4. If you place that unit in the middle of the rack, it will still boost the other components of your system. It might be worth trying.

If I read their web site correctly it seems that they are simply filtering or "Cleaning the mains".

From their website:

"QRT’s proprietary circuitry acts at the source of the problem, reducing EMF noise and RFI interference effects on the mains waveform, audio and video signals – and it does it without limiting the voltage swing or altering the impedance of the AC supply. Which makes the job of your hi-fi’s power supplies and active components much, much easier – and that’s what you hear from your system or see on your screen. Use a QRT purifier and you’ll experience a lower noise floor, greater clarity and separation and increased dynamic range, qualities that are just as apparent (and measurable) when it comes to the color, definition and detail on your AV display as they are in the context of a really great stereo set up. The result? Greater overall musical and visual coherence, more stable perspectives, greater realism."

If someone knows how to do this without using classical EMI and RFI filters they sure have stumped me.

The differences between Quantum devices are too small to be detected. ;)

David12, My QX4 is plugged into the wall and the PurePower 2000 is plugged into the QX4. The CD player and amplifier are fed by the PurePower (no pre-amp). When needed, the PP has reserve in its battery; so, I have not had current problems with my 600 watt per channel RMS amplifier. In fact, the amplifier sounds better going through the PurePower than directly to the wall.

John