QSA 6x30mm Fast Blow Fuse

The fuse in your component is a standard part chosen for price. The QSA 6x30mm fast-blow fuse is a drop-in replacement that Stereo Times' Clement Perry says outperformed every other tweak he's heard, and it takes a minute to install.

A treated fuse, in the standard size, with the standard rating.

The Design

A fuse is a safety part, and QSA builds this one as a drop-in replacement for the standard 6x30mm fast-blow fuse: the same dimensions and the same rating, installed the same way. QSA describes its process as Musical Metal Molecule Alignment Technology (MMMAT) and Metal Active Technology (MAT), which it says make electron flow through the metal more efficient. QSA keeps the details of the process to itself, so we judge it the way Stereo Times' Clement Perry says he does: by listening. QSA lists CCC, CE, UL, and VDE safety certifications for its fuses. Fast-blow fuses open quickly on an overcurrent, and the 6x30mm size is larger than the common 5x20mm.

QSA fuses are directional, and the direction matters. Each carries an arrow, and QSA's guidance is to start with the arrow pointing toward the component's chassis; where the fuse holder sits sideways, try both directions. Perry's first impression was negative until he corrected the orientation, and Greg Voth heard a clear degradation with a fuse installed the wrong way. Turn the component off and unplug it before changing any fuse.

Each step up the ladder is a step up in treatment and in price. Our impressions: Yellow is the entry point and a worthwhile upgrade; Violet sounds more natural and musical; Red is where the QSA character becomes unmistakable; Black/Red steps up image density and resolution; Gold is QSA's reference level. Perry noted that the gaps grow as you climb, with a larger jump from Violet to Black/Red than from Yellow to Violet.

Our Experience

We've installed QSA fuses in our own reference system, in customer systems, and in components we've evaluated, and the improvements have been consistent and significant: more inner detail, better pace and timing, greater naturalness, and a more dimensional soundstage.

Plan for a long burn-in. QSA's guidance is about 24 hours before serious listening, but Perry found the Red/Black needed roughly 600 hours to fully settle, with the Silver still improving through 600. Leaving the system playing on solid-state gear is an easy remedy.

Where It Fits

Open your component's manual or read the fuse itself to find its size, rating, and whether it's fast-blow or slow-blow, then order that exact value; Stereo Times' Mike Wright advises matching the value exactly. If your component uses a larger 6x30mm fast-blow fuse, this is the version. Our advice on level: start at Red or Black/Red if you want to hear what QSA does, then decide whether to go further. Fuses are ordered as needed and can take up to 8 weeks.

Press Recognition

• Stereo Times, Clement Perry (2021), reviewing the QSA fuses. Perry named QSA his Most Wanted Component and Publisher’s Choice for 2021, writing that none of the tweaks he’s heard have matched QSA’s remarkable performance. He also made clear that he judges the products by listening rather than by QSA’s technical explanation. Read the review at Stereo Times
• Stereo Times, Mike Wright and Greg Voth, reviewing the Purple (Violet) fuses. Wright, who calls himself a skeptic, heard more realism, inner detail, and presence in his VAC preamp and amplifiers and gave them his highest recommendation. Voth heard more depth, bass power, and musicality in his power amplifier, and found that orientation mattered. Read the review at Stereo Times
• Stereo Times, Clement Perry, reviewing the QSA Silver fuse and Silver Jitter AC adapter. Perry found the Silver more transparent and dimensional than the Red/Black he had lived with for two years, and reported roughly 600 hours of burn-in. Read the review at Stereo Times

Unsure of your component's fuse type, rating, or the right level to start with? Give us a call before you order, and we'll help you get it right.

Specifications

• Size: 6x30mm
• Type: fast-blow
• Ratings: 250 mA to 20 A
• Levels: Yellow, Violet (labeled Purple), Red, Black/Red, Silver, Gold
• Treatment: QSA MMMAT and MAT
• Directional: Arrow marks direction
• Safety certifications listed by QSA: CCC, CE, UL, VDE
• Ordering: Special order, up to 8 weeks; non-returnable; trade-up program available