Received my Audioquest PowerQuest 707 Power Conditioner yesterday.
Bottom line: I'm keeping it. It significantly improved the overall presentation.
Before installing the 707 my system sounded wonderful and I had no complaints. As to noise: None I could hear even with my ear against the speaker. However I read many reviews where others had a similar situation and yet found an improvement with a PC. I think the more resolving the system the more potential benefit there is with a PC. Especially with Digital components. Noise is Kryptonite to Digital. Maybe analog components such as Turntables and Phone preamps may not benefit as much. But if you have any type of decent setup you should notice an improvement especially if your power is dirty or there is a lot of Wifi, EMF, etc. And remember nearby Solar panels,WiFi and mobile phones and towers can introduce noise not present on the line.
As background my system consists of:
Accuphase P4600 Power Amp
Aurender N20 Streamer
MSB Discrete DAC
Harbeth C7ES-XD Speakers
I chose the 707 because It looks like the sweet spot in the AudioQuest range. It's the top of the PowerQuest line before the Niagra line. Its specs are very similar to the Niagra 1200 plus it includes a heavy duty AudioQuest Power Cable. It reduces both Common mode and Differential noise. It has non-sacrificial surge protection, extreme voltage monitoring and shutdown and Transient Power Correction that offers 45 Amps of transient reserve power for the High Current outlets designed for power amps and sub woofers. That last feature is not included in the 1200 which is $300 more and doesn't include a cable. The unit has 12 outlets:8 for line components and 4 high current for amps. So for $1295 it was a reasonable price and why I decided to try it. So how did it perform?
My system was extremely quiet with no perceived noise but with the PC it added another level of blackness to the background. That allowed minor details in the recordings that I never noticed before to be heard.
The soundstage width and depth were unchanged however the instruments and instrument groupings in the image became more defined. They are more in focus with no smearing between images so imaging was noticeably improved.
The upper frequencies especially strings are more silken and refined. I thought they were that way before adding the PC but after they became even more relaxed and natural.
The overall presentation is more calm, relaxed. Large orchestral climaxes are reproduced without strain, harshness or over brightness in strings and brass.
As a result I found in my many reference tracks I could increase volume 2-3db with no sign of effort.
And of course there is surge and extreme voltage protection.
In my setup I connected my digital sources: Streamer, Network Switch and the Digital power supply of my DAC to the first line bank. Each bank is isolated from each other. I connected the Analog power supply from the DAC to the second line bank. I left the High Current bank empty. At some point I'll try my amp plugged into the PC. For now it remains into the wall. And Accuphase strongly recommends using the wall only.
So overall it's a worthwhile improvement and one that is a bargain considering the impact it has made to my system. I'm sure I could get some additional improvement by moving up to the Niagra 3000 but that is $3900. If I was definitely going to connect the amp to a PC I would consider that as the reserve power is even higher.
As to the noise issue. I appears there is noise that is not readily noticeable until you remove it. Even with good power coming from the wall there are improvements that can be found and I suspect non-line generated noise is present all around us and has subtle effects on the sound.
I will post this review on a new thread as a 707 review for those looking for a PC.
