Quantum Science Audio

QSA 5 x 20mm Orange Slow Blow Fuse

Frais d'expédition calculés à l'étape de paiement.
Valeur du fusible de la science quantique: 100 milliampères
NOTE: Due to the overwhelming number of fuse variables, each fuse is ordered from QSA as they come in. It can take up to 6 weeks to receive your fuse. Keep that in mind when ordering.

Who knew something so insignificant could transform the performance of your audio components? We sure didn't, until we tried the QSA fuses. QSA's proprietary metallurgical treatment process makes their products very powerful component upgrades. One of our top tweaks!

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QSA 5x20 Red Slow Blow Fuses

Who Knew Something So Physically Insignificant Could Sonically Transform Your Audio Components.


"...many high-end audio tweaks I've heard sound great, but none have matched the QSA's remarkable performance. I repeat, none." - Clement Perry, StereoTimes

"Same..." Mike Garner, Tweek Geek

Please Note ALL QSA Fuses Are Special Order & Non-Returnable

    Quantum Sciences & Their Philosophy

    Quantum Sciences has been working on research and development of their fuses for over 22 years. Their proprietary technology removes what they call "bottle neck distortion" making the sound reproduced by your components more alive, unbelievably dynamic with an ultra dark sonic background.

    The Fuse: One Of The Biggest Bottlenecks in Audio Component Performance

    Their belief is that the biggest bottleneck in an audio components' performance is the fuse. all of the power feeding your component (probably from a very expensive power cord) ultimately runs through this tiny filament of wire, a $1 part, before it enters your system. Power cords can an do help, as does power conditioning, but ultimately it is the fuse that is the weak link in the power chain. QSA has spent 22 years working to eliminate this bottleneck. Their line of fuses spans a wide range of performance levels and price points. All are designed to eliminate the distortions created by a typical fuse. The end result are fuses that allow your components to perform their best. Drawing you into the music on an emotional level you might not have thought possible.

    QSA's value proposition and challenge to the customer it that these fuses will outperform the sonic benefits power cords, and cables costing many times more.

    Customer Comments

    - "This thing is amazing! Only 24 hours in but it sounds exactly as you and others have described. I'm thrilled!"- Evan S., Red fuse

    - "After about 3.5 hrs listening, first 1-2 hrs Meh..2-3.5hrs these are SERIOUS fuses, Freakin Amazing at times!"Tom J., Violet and Black fuses

    - "Just to let you know the fuse already arrived today!! I immediately installed it.The effect is fucking bonkers!!!I installed it in my Lampizator Pacific Dac with 300B's Molybdenum tubes from Elrog ... This Dac has turned into a sonic beast! It was already super fast, but this is now a stereoid version of what it used to be... It's insane, and completely what I hoped it would be. The money is heavy, but the sonic result makes it `almost' cheap."- Nico K., Red/Black Fuses

    - "The clarity and quietness of these fuses is uncanny." - Chip F., Yellow fuse

    -"Thanks for the amazingly quick ship on the new QSA fuse! If this is the 2nd from the bottom of their lineup, I can't imagine what some of the higher priced versions do. Installing this in my Decware Torii MK III was a revelation, and I had already tried several other after-market fuses!"- Chris P. Blue Fuse

    Our Impressions

    Our listening tests of the Red Fuse ($1400) convinced in seconds of their value. It is no understatement to say that they are a paradigm shift in our concept of what matters in the audio system. These tiny devices bring out the emotional/musical potential of any component like no other tweaks or accessory we have EVER listened to has. The amount of performance that these fuses allow your component to perform at is well worth the asking price. We guarantee it.

    Bottom Line: These fuses offer the most significant upgrade in sound quality compared to any other accessory, cable, or tweak we have ever tried. It's not even close, they redefine value for high end audio.

    "...$1422 each! That's crazy? I lamented, "This is just way too much to ask for a fuse, sir." Tsang's only response again was, "this fuse will outperform any tweak in your system. Looking at my components, I started taking an inventory. I've some serious tweaks in my space, namely the Novum Resonators, various Entreq ground boxes, Jack Bybee's iQSE Fatboys, alongside Kemp's AC conditioner and Frank Acoustics Ultra Bank products. All are excellent. None are cheap...

    ...Knowing the sonic improvements heard between the standard $28.50 Black series to the $711.00 Purplemodel, I admit, I wasn't sure what to expect. Insuring directionality, I just popped them in and just let the music play for the next 24 hours. Upon my return, I immediately noticed how much of a deafening silence had crept over the system. Weirder was this quiet did not affect the high frequencies negatively whatsoever. In fact, the opposite occurred. The top-end opened up with a sense of relaxation and ease, which aided a remarkable sense of brilliance. Bass was quicker afoot and possessed details that made me sit up and pay closer attention. Voices appeared more transparent but with more harmonic realism, flesh tone, and focus. Out of all these obvious improvements, the absolute lack of noise stood out the most. The top-end sparkle improved with more excellent sparkle, weight, and shimmer (yes, cymbals carry weight). All in all, the QSA Red series fuses introduced an altogether different sonic fabric that is rarely associated with digital sources and its playback - regardless of format or resolution. This, dear reader, is the magic of analog!..."Clement Perry, StereoTimes

    What Reviewers Are Saying

    Not one, but THREE Stereotimes reviewers have given QSA fuses their endorsement for 2020 Most Wanted Components. Read below to see what each reviewer had to say. Full Article
    publisherschoice2020.jpgQuantum Science Audio Ultra High-End Fuse($2,844 ea):"...Upon placing two of the QSA Red/Black fuses in each Behold amplifier (I have two amps which require two fuses each - plus an extra fuse for my preamp), I turned up some music and just sat there slackjawed.The room filled with sounds from the studio I never detected before. When cymbals hit, the rivets sounded like rainfall. WTF is going on??? The music developed a renewed sense of PRaT that it never had prior. The music began flowing out of my loudspeakers in a way that closely resembled the Audio Note gear in my downstairs rig. That's an 8-watt 300B SET setup and sounds ever so sweet and delicate. The upstairs rig is more like a 600 lbs gorilla - with wings: bigger and bolder, but with the same earmarks that relay the music in the purest sense of the word. These are sonic enhancements said to be impossible to achieve from solid-state components and digitally-based systems. Not True.
    ...The QSA doesn't sound like a significantly impressive-sounding fuse as much as it sounds like ahidden technologyhoused insideof a significantly impressive-sounding fuse. The QSA Red/Black fuses somehow freed up what I can only describe as bottlenecking occurring inside the amplifier and directly at the fuse-holder. ...Yes, the QSA products are insanely expensive, as are a lot of things in our hobby. But make no mistake, the QSA Red/Black fuses are also about the most impressive after-market tweak to have graced my listening space. Yick Man was right; his fuses do sound as good as any $10,000 AC cords I've owned. (Review in the works Clement Perry)

    Quantum Science Audio Ultra High-End Fuse($2,844 ea):My first reaction to hearing about the benefits of changing to these fuses was incredulity, to say the least. Then, when learning the price, I actually laughed out loud and said ”no way, I don't give a s**t what they do.” I now have to admit that I have to eat those words. The sonic improvements these fuses make are simply astonishing and that is an understatement. In my system (Behold BPA768 amp & pre-amp), there were immediate and DRAMATIC improvements in every aspect of sound that you can think of, (bass, midrange purity, sweet highs, immense soundstage, etc.) with the result that everything becomes more like the real thing and listening pleasure is increased to a level that continues to amaze. Are they worth the money? Let's just say I, and others, have spent far more for an improvement in sound that falls far short of what these things do. (Ron Cook)

    Quantum Science Audio Ultra High-End Fuse ($2844 ea): "... Once installed I could not believe the effect that took place in my system after a 24-36 hour break-in period. My system was currently functioning at an exceptionally outstanding high level. I thought any improvement in the sound, going forward, would be a small one. Boy, was I wrong! These tiny miracles allowed my system's current significant attributes to expand beyond what I thought possible. Every characteristic we lovers of music hold important in sound reproduction became so much more pronounced. I'm delighted to say that at least four Stereo Times colleagues who now have these fuses in our systems have all experienced a similar dramatic result...this is one time where all of us who took the plunge feel it was well worth the cost. This is why I have chosen this QSA fuse as my 2020 Stereo Times Most Wanted Component. (Dan Secula)

    What Customers Are Saying

    Chris S.

    The QSA Top of the Line Fuses

    I have 4 components - Power Conditioner, Transport, DAC and Amplifier. All four have the Red/Black fuse installed. I installed the first three fuses six weeks ago and just installed the Amplifier fuse three days ago. My experience with burn in is interesting. After five weeks, the first three fuses were still improving the sound - still getting better every day (although it is decreasing). This is fun because the stereo sounds better every day even though I have done nothing. Of course the sound changes the most in the beginning; the first few hours it changes a lot. The same is true for the first few days - big improvement every day! Some highs (like a triangle or bell) didn't sound right for the first 2 days, but then they were better than ever.
    • The Sound
      • General Impressions
        • Everything sounds more beautiful
        • There is more emotion in the music
      • Specific Impressions
        • Much lower noise floor
        • More micro-detail is revealed
        • There is less glare (I didn't even know I had glare!)
        • Individual voices and instruments are more apparent
        • They don't blur together when massed together
        • I think it is called individuation
        • The soundstage is deeper, wider and higher
        • The sounds are more solid in the soundstage
        • There are no gaps in the soundstage
        • Everything sounds natural
        • Frequency Response is linear at all volumes
        • Understanding lyrics is much easier
        • Bass goes deeper than before
        • Bass is better defined and easier to follow

    The music just "pulls you in." You don't want to stop listening - very addictive.

    These changes have been The single best tweak I have ever made! And I have been tweaking my stereo for 40 years.


    These fuses are directional, as indicated by the arrows. If after installing the fuse the music sounds thin, harsh and brittle you may have it facing the wrong direction. Try reversing the direction of the fuse and listening.


    Break In

    Most of the break in is done in the first 24 hours. But they will continue to improve and change for up to a month in some instances.

    More Than One Fuse

    If your amp or any component has multiple fuses inside, the most important fuse to upgrade is the mains fuse. The mains fuse is usually the one with the fuse holder on accessibleon the outside of the component, or on the inside right wherethe power is connected initially. Replacing the other fuses has a very minimal effect.


    The QSA fuses are warranted from defects for 1 year.


    If you cause the fuse to accidentally blow during the warranty period, we will replace it one time.