With balanced isolation transformers, the Niagara 7000 is an 86 lb. beast.
There's no reference system without linear power correction
Garth Powell, the designer of the Niagara 7000, has an elegantly simple way to prove that his black box works. It's called the difference file.
Digitally record the output of your DAC or preamp (or entire system at the speaker cables if you have the right equipment) with the system plugged into the wall, and then plug it into the Niagara 7000 and record the same track. On a computer, align the recordings perfectly, flip the phase on one track and sum them. This causes the matching parts cancel out. If the two tracks are identical, the difference file would be totally silent. If the power conditioner is making a difference, the difference track will have sound: you will hear everything that was masked in the direct-from-wall playback.
The Niagara 7000 offers transient power correction, allowing connection of power amps and subwoofers. We got the chance to hear two difference tracks, one from a Niagara 7000 and one from an unnamed power conditioner at about the same price point. We weren't sure what we'd hear—maybe some squeals and howls and clicks? We were startled to hear music. It was metallic and thin, but we could clearly hear a crowd cheering and clapping and then instantly identified the opening bars of 'Mediterranean Sundance / Rio Ancho' from Friday Night in San Francisco by Paco de LucÃa, John McLaughlin, and Al Di Meola.
That's a lot of information to lose, and that's between two power conditioners. The difference is even more pronounced when the system is plugged straight into the wall.
"Power Conditioners Are Not for Power Amps"
The engineering challenge for a power conditioner is not to remove noise, but to remove noise linearly across all the octaves. Otherwise, says Garth, "It'll act like a dynamic graphic equalizer."
But what of the popular wisdom that power conditioners work on low-current and steady-current devices such as DACs, phonostages, and preamps, but are not for power amps and powered subwoofers? The thinking here is that power conditioners aren't able to supply the transient current demands of power amps, and thus act like compressors, greatly blunting dynamics.
Enter "transient power correction" and the four high-current outlets you see on the left in the photo above. These outlets have less noise dissipation, allowing for lower impedance and greater current delivery, but more importantly, the Niagara has a current reservoir, supplying up to 90 amps over 25 milliseconds. This is more than enough current and time to cover all those demanding leading edges. Not only can you connect power amps, but you should, because they get more dynamic and immersive on a Niagara.
If you have a high-end setup, the AudioQuest Niagara 7000 is an essential component to push your components to their full capability. Think of it as finding a great road or track for your sports car, and not confining it to potholed city streets. If the 7000 is above your budget, AudioQuest pours much of its technology into the Niagara 5000 and Niagara 3000, each at lower prices but designed for the highest fidelity systems.