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What You Need to Know
What Is a Power Conditioner, and Why Might You Need One?
The AC power in your home runs on technology that’s about 100 years old. It was built for light bulbs and electric motors. It was never built for the audio and video gear we use today.
Modern homes are full of noise on the AC line. WiFi, cell signals, dimmer switches, LED bulbs, and computer power supplies all add electrical noise — and so do your neighbors’ homes.
AudioQuest has measured what this does. Up to a third of a high-resolution audio signal can be lost or covered up by AC noise before it ever reaches your speakers. Once that detail is gone, no other piece of gear can bring it back.
A power conditioner sits between the wall and your equipment. It filters out the noise, gives your amp the current it needs on big musical peaks, and protects your gear from voltage spikes and surges.
In our experience, a good power conditioner will almost always noticeably improve the sound of any high-end audio system. The PowerQuest 505 brings real AudioQuest engineering — the same surge protection, the same wide-bandwidth filtering, and the same included power cable as the higher-end 707 — at a price that lets almost any serious system benefit.
What Makes the PowerQuest 505 Notable?
The PowerQuest 505 was designed by Garth Powell, AudioQuest’s Senior Director of Engineering — the same designer behind the reference Niagara line. It sits in the middle of the PowerQuest lineup, above the 303 and below the 707, and it carries forward most of the features that matter for a clean, quiet power feed.
Ultra-Linear Noise-Dissipation — Greater Than −22 dB
The 505 attacks AC line noise across a wide bandwidth. It runs a 30 kHz – 1 GHz Differential Mode filter plus a 30 kHz – 100 MHz Common Mode filter.
Together they handle the two kinds of noise that most commonly plague AC power: noise riding between hot and neutral, and noise riding on both conductors together. What this means: quieter backgrounds, better fine detail, and a picture with more contrast and punch.
Twelve Outlets, Two Purpose-Built Banks
Four High-Current outlets for your amplifier, integrated amp, powered subwoofer, or powered speakers — components that need more current on musical peaks.
Eight Linear-Filtered outlets for your source gear: streamers, DACs, CD players, preamps, phono stages, TVs, game consoles, routers, and networking gear. Each bank is engineered for the kind of draw behind it.
Non-Sacrificial Surge Protection
Most surge protectors are “sacrificial” — they work once. After a big surge, the parts inside are used up and the unit stops protecting your gear, even though it still passes power.
The PowerQuest 505 doesn’t work that way. It’s rated to withstand repeated 6,000V / 3,000A surges — the most that can pass through a home’s electrical panel — without wearing out.
Extreme Voltage Shutdown adds a second layer of safety. If incoming voltage goes above 140VAC, the main relay opens in under a quarter of a second. It resets on its own once power is safe.
A Proper AudioQuest Cable in the Box
And crucially at this price point: the 505 ships with a proper AudioQuest PQ-715 power cable already included. It’s a 2-meter detachable cable with Semi-Solid Long-Grain Copper conductors, ZERO-Tech for uncompressed current, and RF/ND-Tech for noise dissipation.
The plug is flat-to-wall for tight installations. Many conditioners at this price ship with a generic cord from a bin, or no cord at all. The 505 comes ready to run.
What the Pros Are Saying
Alpha Audio reviewed the PowerQuest 505 as part of a three-way group review of the 303, 505, and 707, putting each unit on their test bench with deliberately noisy switching amplifiers in the system. Their consistent observation across the PowerQuest line: overall noise drops and there’s less audible impact from the dirty amplifier with a PowerQuest plugged in.
Most reviews and customers say the same things about the 505: darker backgrounds, more clarity in the midrange, and a cleaner soundstage. For home theater users, the picture contrast also gets a clear bump once the AC is cleaned up.
How Does It Connect to Your System?
The back panel has 12 total outlets arranged in two banks, and it matters which outlet you use for what:
Four High-Current outlets — for your power amplifier, integrated amp, AV receiver, powered subwoofer, or powered speakers. These are engineered for gear that pulls more current on musical or dynamic peaks.
Eight Linear-Filtered outlets — for your lower-draw gear: streamers, DACs, CD players, preamps, phono stages, TVs, media players, game consoles, routers. These get the heaviest filtering for the quietest background.
The 505 is a rack-friendly 3.4” tall, 17” wide, and 13.4” deep, and weighs just 10.8 lbs — so it slots easily into any rack or sits neatly on a shelf. Rack-mount ears (2-RU) are included in the box.
The 505 ships with its own AudioQuest power cable — the detachable 2-meter PQ-715, with a flat-to-wall plug for tight installations. Plug it into the wall, plug your gear into the 505, and you’re running.
Who Is This Product Best For?
You have a nicely-assembled stereo or home theater system and you want the next layer of improvement — a quieter, cleaner foundation for everything you’ve already invested in.
You want real AudioQuest engineering — Ultra-Linear Noise-Dissipation, Non-Sacrificial Surge Protection, common- and differential-mode filtering — without stepping up to the Niagara line.
You’re putting together a multichannel home theater system and you need surge protection plus noise filtering across 12 outlets, with a rack-ready form factor.
You want a turnkey solution. The 505 ships with a proper AudioQuest power cable already in the box — no extra buy required to plug it in.
You don’t need the 707’s 45-amp Transient Power Correction circuit — either because you’re running an integrated amp with more modest current demand, or because you’re primarily powering home theater gear with their own high-quality internal power supplies.
Building Your System? Here Are Some Great Companions.
The 505 ships ready to run with the included PQ-715 cable. Two clear upgrade paths beyond that:
- Upgrade the wall cable — AudioQuest NRG-X3. The next step up from the included PQ-715. Perfect-Surface Copper (PSC) conductors, AudioQuest’s RF/ND-Tech for noise dissipation, and Direction-Controlled winding. A small upgrade that’s easy to justify on a budget. Browse AudioQuest NRG cables.
- Ultimate upgrade — AudioQuest NRG-Z3. The full hi-fi+ 2025 Award Winner — 7-strand semi-solid concentric Perfect-Surface Copper, silver-plated shield conductors, and the strongest noise-dissipation topology in the NRG series. If you want to push the 505 as far as it can go, the NRG-Z3 is the way. Shop NRG-Z3.
- Step up within the PowerQuest line. If you run a high-current power amplifier, consider the PowerQuest 707 (same form factor, adds 45-amp Transient Power Correction) or the 20-amp flagship PowerQuest 909.
- Component cables. Upgrading the cables running from the 505 to each of your components is the natural next step after the conditioner itself. Browse all AudioQuest power cables.
Features & Specifications
Twelve Outlets, Two Purpose-Built Banks
Four High-Current outlets for your amplifier, AV receiver, powered subwoofer, or powered speakers. Eight Linear-Filtered outlets for your lower-draw gear — streamers, DACs, preamps, TVs, game consoles, networking gear.
Ultra-Linear Noise-Dissipation > −22 dB
Wide-bandwidth linear noise reduction — not just a narrow window. The 505 addresses both differential-mode noise (riding between hot and neutral) and common-mode noise (riding on both conductors together) for consistent improvement across the audio and RF spectrum.
Non-Sacrificial Surge Protection
Withstands repeated surges of up to 6,000V / 3,000A — the maximum that can pass through a home’s AC electrical panel — without wearing out. Most surge protectors use MOVs that degrade every time they absorb a surge. The 505 doesn’t.
Extreme Voltage Shutdown
If incoming AC voltage rises above 140VAC, the main power relay opens in under 0.25 seconds to protect connected gear. It resets automatically once line voltage returns to a safe range.
AudioQuest PQ-715 Power Cable — Included
A proper 2-meter detachable AudioQuest power cable is in the box, using Semi-Solid Long-Grain Copper conductors, ZERO-Tech for uncompressed current transfer, and RF/ND-Tech for noise dissipation. The plug is a flat-to-wall design for tight installations.
Compact, Rack-Ready Form Factor
At just 3.4” tall (3.5” with feet) and 10.8 lbs, the 505 is easy to place on a shelf or in a rack. A 2-RU rack-mount kit is included in the box — not optional, not sold separately.
Designed by Garth Powell
AudioQuest’s Senior Director of Engineering and the designer of the entire Niagara and PowerQuest lines. Powell is widely regarded as one of the top power-conditioning engineers in the audio industry.
Quick-Reference Specifications
| Power & Filtering | |
| Rated Current | 15 Amps (RMS) @ 120V |
| Ultra-Linear Noise-Dissipation | > −22 dB |
| Differential Mode Filter | 30 kHz – 1 GHz |
| Common Mode Filter | 30 kHz – 100 MHz |
| Surge Protection | Non-Sacrificial, withstands repeated 6,000V / 3,000A surges |
| Extreme Voltage Shutdown | 140VAC; relay opens <0.25s; auto-resets when safe |
| Outlets | |
| Total Outlets | 12 |
| High-Current Outlets | 4 |
| Linear-Filtered Outlets | 8 |
| Main Power Cable | 2m detachable PQ-715 (Semi-Solid LGC, flat-to-wall plug) — included |
| Dimensions & Weight | |
| H × W × D | 8.6 × 43.2 × 34.0 cm (3.4” × 17” × 13.4”; 3.5” H with feet) |
| Weight | 4.9 kg (10.8 lbs) |
| Rack Mount | 2-RU rack-mount kit included |
| Warranty | |
| Standard Warranty | 5 Years |
Frequently Asked Questions
Frequently Asked Questions
Will this actually improve the sound of my system?
In our experience, a good power conditioner will almost always noticeably improve the sound of any high-end audio system. AudioQuest states the PowerQuest 505 reduces AC noise with Ultra-Linear Noise-Dissipation across a wide bandwidth, and protects your gear from surges.
Results vary depending on how dirty your AC is, how detailed your system sounds, and how much noise your other gear injects onto the line. Most users report darker backgrounds, better detail, and — in home theater — a noticeable bump in picture contrast.
Which outlets do I plug my amp into, and which are for my source gear?
Plug power amplifiers, integrated amps, AV receivers, powered subwoofers, and powered speakers into the four High-Current outlets (clearly labeled on the rear panel). Plug streamers, DACs, CD players, preamps, phono stages, TVs, game consoles, and networking gear into the eight Linear-Filtered outlets — they get the heaviest filtering for the quietest background.
Will a power conditioner limit the dynamics of my amplifier?
Many conditioners do choke the current an amp can draw on musical peaks. The PowerQuest 505 provides four High-Current outlets engineered for amplifiers and other variable-current gear.
If you own a high-current power amp that pulls serious current on peaks, the step-up PowerQuest 707 adds Transient Power Correction — a 45-amp peak current reservoir.
For small-to-medium amplifier demands, the 505 is the right choice. For high-current amps, consider the 707 or the 20-amp PowerQuest 909.
Do I need this if I already have a good surge protector?
Surge protection and power conditioning are two different jobs. A basic surge strip blocks voltage spikes but does nothing for AC noise — and most use throwaway MOV parts that wear out with every surge.
The 505 handles both jobs at a high level: Non-Sacrificial Surge Protection that withstands repeated 6,000V / 3,000A surges, plus dual differential-mode and common-mode filters that no surge strip can provide.
Do I need to buy a separate power cable?
No — the 505 ships with a 2-meter AudioQuest PQ-715 detachable power cable already in the box. It uses AudioQuest’s Semi-Solid Long-Grain Copper conductors, ZERO-Tech, and RF/ND-Tech, with a flat-to-wall plug.
It’s a genuinely good cable, ready to use out of the box. If you later want to upgrade, AudioQuest’s NRG-X3 or NRG-Z3 are the natural next steps.
How does the PowerQuest 505 compare to the 303 or the 707?
The PowerQuest 303 is the entry point. It has the same 12-outlet form factor and Non-Sacrificial Surge Protection, but filters differential-mode noise only (no common-mode filter).
The 505 adds a 30 kHz – 100 MHz Common Mode filter — addressing the noise that most commonly plagues modern AC lines (switching power supplies, LEDs, wireless devices).
The 707 goes further still: wider 30 kHz – 1 GHz common-mode bandwidth, plus a 45-amp Transient Power Correction reservoir that protects amplifier dynamics.
Pick the 505 if you’re running mainly home theater or moderate two-channel gear. Pick the 707 if you have a power amp whose dynamics matter.
Is the surge protection guaranteed? What happens after a surge?
AudioQuest’s Non-Sacrificial Surge Protection is rated to withstand repeated 6,000V / 3,000A surges — the most that can pass through a home’s electrical panel — without needing to be replaced. There’s no joule threshold after which protection stops.
Extreme Voltage Shutdown adds a second layer. If incoming voltage exceeds 140VAC, the main relay opens in under a quarter second. The PowerQuest 505 itself comes with a 5-year warranty.
See It in Action — Garth Powell on AudioQuest Power Conditioners
AudioQuest’s Senior Director of Engineering, Garth Powell, designed the entire PowerQuest line. In this discussion from AudioQuest’s official channel, Garth explains the first principle behind his power-conditioner designs: a power amplifier’s first job is unrestricted current delivery to the loudspeaker, and nothing in the AC chain should impede that transfer of energy.
What’s in the Box
- AudioQuest PowerQuest 505 Power Conditioner
- Detachable 2m AudioQuest PQ-715 power cable (Semi-Solid LGC, ZERO-Tech, RF/ND-Tech, flat-to-wall plug)
- Four pre-installed rubber feet
- Two 2-RU rack-mount brackets and mounting hardware
- Owner’s manual and warranty documentation
- 5-year warranty
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Want to learn more about power conditioning and how it affects your audio system? Visit our Learning Center for guides, tips, and expert advice. For a deeper technical dive from AudioQuest’s Senior Director of Engineering, Garth Powell, download AudioQuest’s “Power Demystified” whitepaper.
