AudioQuest PowerQuest 303 Power Conditioner (Schuko)

The AudioQuest PowerQuest 303 is a power conditioner in 2U rack format that splits seven Schuko outlets into three high-current and four filtered outputs, and comes with a matching power cable right out of the box.

It's the entry point into AudioQuest's current rack generation: not some little strip to tuck behind the sideboard, but a unit you install and then forget about. That's exactly how power supply should be.

Why the PowerQuest 303?

Instead of a simple filter, the PQ 303 works with AudioQuest's Ultra-Linear noise dissipation: more than 22 dB of push-pull attenuation from 30 kHz to 1 GHz, evenly across the whole range. That's exactly where cheap filters fall short — they attenuate hard in one narrow window and build up resonance peaks elsewhere. Three low-impedance high-current outlets are reserved for amplifiers, active speakers, and subwoofers; four filtered ones take the sources. Overall, the unit can be loaded with up to 10 amps.

What you get

A metal chassis in full rack width, complete with 2U mounting brackets — included, not sold separately as so often happens. The surge protection is destruction-free and withstands repeated tests at 6000 volts or 3000 amps; at 270 volts mains voltage, the unit disconnects itself automatically. And the cable to the wall is already in the box: a direction-controlled PQ-416, two meters long.

Who is the PowerQuest 303 for — and who isn't it for?

Honestly: if you want to optimize display devices separately or protect network and antenna lines, reach for the PowerQuest 3 instead. If you're looking for more headroom for large power amps, you'll find it in the 505 or 707. For a tidy hi-fi rack with one to three amplifiers and a few sources, the 303 is the right basic setup.

Our verdict

The PowerQuest 303 is unglamorous groundwork done right: properly filtered, properly shielded, properly cabled — and with the included PQ-416, no hidden follow-up costs. Not a unit chasing spec-sheet records, but one that brings exactly the calm to many systems that was missing before. Whether it's the right size for you, we'll quickly work out together: HD Zürisee in Wädenswil, 044 680 22 00, WhatsApp 076 534 22 00 (text only, no calls), shop@hdzuerisee.ch.

Technical data

• Device type: power conditioner / mains filter, Schuko version (EU), 2U rack-mountable
• AC outlets: 7 (3× high-current, 4× linearly filtered)
• Max. input current: 10 A RMS at 220–240 V
• Noise dissipation: Ultra-Linear (RF/ND-Tech), push-pull over 22 dB from 30 kHz to 1 GHz
• Transient Power Correction: not present (see PowerQuest 707)
• Surge protection: destruction-free, 6000 V / 3000 A; extreme-voltage shutoff at 270 VAC
• Power cable: AudioQuest PQ-416, 2 m, direction-controlled, included
• Dimensions (W×H×D): 43 × 8.6 × 34 cm (9 cm H with feet)
• Weight: 4.65 kg
• Included: PowerQuest 303, PQ-416 power cable (2 m), 2U rack brackets, user manual

Frequently asked questions

Is a power cable included?

Yes, a direction-controlled AudioQuest PQ-416, two meters long. That means the unit is ready to use right away, which is by no means a given for mains filters in this class. A higher-grade power cable remains possible as a later upgrade — we'll tell you when that's really worth it.

Does the PowerQuest 303 fit in my rack?

Yes. The chassis is full rack width and two rack units tall, and the mounting brackets are included. Without feet it's 8.6 centimeters tall, with feet 9 centimeters. It works just as well freestanding — just plan enough space behind it for seven Schuko plugs.

How much current can the PowerQuest 303 handle?

Ten amps RMS in total at 220 to 240 volts. The three high-current outlets are enough for integrated amps, power amps, or active subwoofers of typical size. For very powerful power amps in continuous use, you should reach for the Niagara 3000 instead, which allows 15 amps.

Why buy the PowerQuest 303 at HD Zürisee?

Because we like to do the math before we sell: what's hanging on the system, how much current does it draw, is the 303 enough or do you need more? As an authorized dealer, we then also handle installation, service, and warranty — with our own in-house technician.

Pairs well with

In a rack, order pays off: more filters are in Mains Filters & Power Conditioning, cables for the connected devices under Power cables, and the brand's full range in the AudioQuest world.