AudioQuest PowerQuest 505 Power Conditioner (Schuko)

The AudioQuest PowerQuest 505 is a rack-mountable power conditioner with seven Schuko outlets, the first in the line to also filter in common mode, clearing out a significantly broader spectrum of interference.

There's a price gap between the no-frills 303 and the Niagara league. The 505 fills it — without you having to rebuild your rack or empty your account.

Why the PowerQuest 505?

The PQ 303 works only in push-pull mode. The 505 adds a second filter stage on top: common-mode attenuation from 30 kHz to 100 MHz, also at more than 22 dB. That catches exactly the interference that today comes from Wi-Fi routers, mobile networks, powerline adapters, and LED drivers, which use power cables as an antenna. Combined, that's roughly 19 octaves of ultra-linear noise dissipation. Three low-impedance high-current outlets stay reserved for amplifiers, four filtered ones for sources, with a total allowance of 10 amps.

What you get

A metal chassis in full rack width with 2U brackets in the box, destruction-free surge protection up to 6000 volts or 3000 amps, and shutoff at 270 volts. Included is the PQ-715, a direction-controlled power cable made of LGC copper with AudioQuest's ZERO-Tech and RF/ND-Tech — so the technology sits in the cable, not the outlets. A sensible starting point you can still upgrade later.

Who is the PowerQuest 505 for — and who isn't it for?

Straight talk: for a compact chain of an integrated amp and a streamer, the 505 is more than needed — a PowerQuest 2 or 303 is enough there. If you need power reserves for impulse-hungry power amps, you'll only find them in the 707 or the Niagara line. The 505 is made for ambitious hi-fi systems sitting in an RF-polluted living environment.

Our verdict

The 505 is the point where mains filtering stops being an accessory and starts becoming a component. fairaudio reached the same conclusion: "The playback comes across as a bit calmer, the spatial structure stabilizes and grows in its dimensions." – Michael Bruss, fairaudio, April 2026, awarded the "Kauftipp" (Buying Tip) rating. Whether the 505 or the 707 belongs in your system is something we're happy to discuss: 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 / broadband mains filter, Schuko version (EU), 2U rack-mountable
• AC outlets: 7 (3× high-current, 4× ultra-linearly filtered)
• Max. input current: 10 A RMS at 220–240 V
• Noise dissipation: Ultra-Linear across roughly 19 octaves — push-pull over 22 dB (30 kHz–1 GHz), common-mode over 22 dB (30 kHz–100 MHz)
• Transient Power Correction: not present (only PowerQuest 707 and the Niagara series)
• Surge protection: destruction-free, 6000 V / 3000 A; extreme-voltage shutoff at 270 VAC
• Power cable: AudioQuest PQ-715, direction-controlled, LGC copper, with ZERO-Tech and RF/ND-Tech, included
• Dimensions (W×H×D): 43 × 8.6 × 34 cm (9 cm H with feet)
• Weight: 4.9 kg
• Included: PowerQuest 505, PQ-715 power cable, 2U rack brackets, user manual

Frequently asked questions

What is ZERO-Tech, and where does it sit?

ZERO-Tech is AudioQuest's conductor geometry with no characteristic impedance, and it sits in the included PQ-715 power cable, not in the unit's outlets. It's meant to transfer current without compression. The effect shows up mainly at the connection to the wall outlet — right where all the current has to pass through.

What's different between the PowerQuest 505 and the 303?

The 505 additionally filters in common mode from 30 kHz to 100 MHz, covering roughly 19 octaves. It also comes with the higher-grade PQ-715 power cable. Outlets, rack format, and current capacity are identical — the difference is in filter quality, not capacity.

Is the 505 enough, or should it be a Niagara?

For most ambitious hi-fi systems, the 505 is enough. Once several large power amps come into play, or you exceed 10 amps, the Niagara 3000 or 5000 becomes the better solution. Tell us what's being connected, and we'll work it out together.

Why order the PowerQuest 505 from HD Zürisee?

Because we know the whole line side by side and can tell you where stepping up is worth it — and where it isn't. Add to that everything that makes a specialty shop by Lake Zurich what it is: personal advice, an in-house technician, and warranty handling we take care of for you.

Pairs well with

The included cable can be upgraded later: the selection is under Power cables. Larger models are in Mains Filters & Power Conditioning, the full range in the AudioQuest world.