Quantum Science Audio (QSA) Yellow Entry Level Slow-Blow Fuse

Item code: QSA Yellow Slow

4.8 10 reviews ✓ Verified
Future Shop are very excited to introduce Quantum Science Audio, the undisputed heavyweights in the audiophile fuse space. With more than 22 years of research into what they call 'Bottle Neck Distortion', QSA products can enhance your enjoyment of yo…
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SPEAKER CABLES:

A quantity of 2 means you will receive a pair of speaker cables e.g. for your front left and front right speakers. By entering a quantity of 1, you will get a cable for a single speaker e.g. centre speaker and this option also enables you to vary the length (and termination) of your cable for each speaker.

OTHER CABLES:

A quantity of 1 means you will receive a single cable in the case of aerial, satellite, subwoofer, digital coaxial & optical cables and a pair of cables in the case of 2 rca to 2 rca analogue audio cables.

NON-CABLE PRODUCTS:

A quantity of 1 means you will receive 1 of the specified products.

£166.67 ex. VAT
Available — built to order, dispatches in 48 Hours
Delivery: Royal Mail Tracked 24 FREE  ·  DPD Next Day from £8.95  ·  DPD Saturday from £12.95
Order before 4pm (Mon–Fri) for same-day dispatch
Our promise: 30-day returns · Free burn-in · Built in our UK workshop · 12 Months warranty · Expert support on every order

Quantum Science Audio (QSA) Yellow Entry Level Slow-Blow Fuse

 

Please note: we cannot guarantee that all fuse ratings will be in stock, so longer lead times may apply.

Future Shop are very excited to introduce Quantum Science Audio, the undisputed heavyweights in the audiophile fuse space. With more than 22 years of research into what they call 'Bottle Neck Distortion', QSA products can enhance your enjoyment of your system in a way that is remarkable for such a small component, until recently considered irrelevant by many in the industry. Since all current that enters a power cable or component in your system must pass through the fuse before it proceeds, the quality- or lack thereof- of the fuse can make a drastic difference to your system's performance. QSA fuses aim to reduce the negative effects of what QSA describe as 'bottlenecking', which can help your system perform to its full potential.

Much of this may sound outrageous, but only to those who have not had the chance to hear it for themselves. Having conducted our own listening tests, and based on external feedback, we are convinced that these fuses- all the way through the range- offer an upgrade to a system that can match components many times the price.

The Yellow fuse is another significant step up from QSA's Light Blue fuse. It may be entry-level by QSA's standards, but it will still outperform fuses from any other brands at higher prices.

 

Stereo Times Awards

"I can tell you this: many high-end audio tweaks I've heard sound great, but none have matched the QSA's remarkable performance. I repeat, none." (Read More...)

Product Review - Clement Perry, Stereotimes - Most Wanted Components 2020, 2021 & Publisher's Choice 2021, 2022

 

 

Please note: fuses are directional, so please ensure you install your fuse accordingly. If you are not sure on the correct direction, simply try it both ways- you will be able to hear the difference.

 

About Quantum Science Audio (QSA)

Quantum Science Audio (QSA) is a company that focuses on designing and manufacturing high-end audio equipment and accessories. QSA is committed to incorporating advanced technologies and scientific principles into its audio products. It aims to push the boundaries of audio reproduction by applying concepts from quantum physics and other scientific disciplines. QSA believe that by harnessing the power of quantum science, they can create audio systems that deliver exceptional performance and fidelity. The company's product lineup typically includes a range of audio accessories. These products are designed with attention to detail and often feature innovative engineering techniques and materials.QSA's focus on incorporating quantum science into their audio solutions sets them apart from more traditional audio manufacturers. They aim to provide audiophiles and music enthusiasts with a unique listening experience beyond conventional audio reproduction.

QSA specialises in manufacturing QSA home audio fuses. QSA Home Audio Fuses are designed to enhance your audio setup by potentially reducing the noise floor in your system. The range consists of 9 different fuses, each offering a unique level of performance enhancement. The entry-level black fuse serves as a starting point, while the gold fuse, positioned at the top end of the range, is claimed to deliver notable improvements to the noise floor. The listening experience is subjective, and individuals are encouraged to audition the fuses themselves to assess the impact on their audio system. QSA fuses aim to minimise bottle-neck distortions, potentially resulting in a quieter background that allows the music to emerge with improved dynamics and liveliness.

QSA products incorporate Quantum Science Audio's proprietary technologies, including Musical Metal Molecule Alignment Technology (MMMAT) and Metal Active Technology (MAT). These technologies aim to promote efficient electron flow and enhanced conductivity within the products.

It is important to note that individual experiences and results may vary when using audio fuses, and personal preferences play a significant role in evaluating their impact on audio systems.

QSA takes pride in its team of audiophile engineers who strive to design top-of-the-line audio products. The company aims to deliver natural sounds, rhythms, and music that resonate with listeners deeply and emotionally. With their groundbreaking science and technology, QSA accessories offer a new generation of audio enhancement, allowing users to experience greater detail and clarity in their audio playback. Quantum Science Audio products are designed to provide audiophiles with a transformative audio experience, uncovering new depths and nuances in their favourite music.

 

We use Royal Mail 1st Class services for our Standard Delivery.

Orders received before 4.30 pm Monday to Friday are usually dispatched the same day by FIRST CLASS post (unless premium postal or timed courier services are selected), subject to stock availability. This does not apply to custom-length cables and speaker cables as these require a longer timescale to terminate. This also excludes all cables selected for the burn-in service. Please note, we do not process orders on national holidays in the UK. Over 98% of our orders are delivered the next working day including Saturdays.

Standard delivery is usually within 2 working days, although 98% of all orders are delivered the next working day including Saturdays. In extreme cases, such as delivery to the Highlands and Islands, this may take 3 days.

All items are fully insured and come with an invoice from Future Shop. We use the Royal Mail for delivery of small packages and DPD Local or DHL for items that weigh over 2KG. Items over 2KG are fully insured and will usually be delivered within 48 hours of placing your order subject to stock availability. For international orders, we use FedEx or DHL services where customers have selected this option.

 

 

Please note, special orders for non-standard cable lengths may be subject to longer deliver time-scales. This may vary from manufacturer to manufacturer.

 

We offer 'Free delivery on orders over £99' subject to the following terms & conditions:

  • Applies only to orders with £99 or more of items (including VAT at the UK rate), at Future Shop
  • Free Delivery on orders over £99 utilises Royal Mail First Class postal service for items weighing under 2KG. For items weighing over 2KG, we use DPD or DHL next working day services which deliver from 9.00am to 6pm within mainland UK (excludes Royal Mail Special Delivery Services and timed next day delivery services by DPD or DHL).
  • Applies only to deliveries to addresses within mainland UK and Northern Ireland addresses. Applies only to orders that are to be delivered to a single Mainland UK delivery address.
  • You will not be eligible for free delivery on your order if any items are cancelled or returned for a refund, bringing the total order amount below £99. Where items are returned, the refund due will be the cost of the item less any postage costs.
  • We reserve the right to change or discontinue 'Free delivery on orders over £99 promotion at any time.
  • FREE DELIVERY FOR ORDERS OVER £99 OFFER DOES NOT APPLY TO TRADE CUSTOMERS.

UK Postal & Delivery Charges - FIRST CLASS

Free UK delivery on all orders over £99*

Weight Price (FIRST CLASS UK POSTAGE)
0000g – 1000g £ 3.95
1000g – 1400g £ 4.95
1400g – 1800g £ 5.95
1800g – 2000g £ 6.95
2000g – 3000g £ 8.95

* Free Delivery on orders over £99 utilises Royal Mail First Class postal service for items weighing under 2KG. For items weighing over 2KG, we use DPD or DHL next working day services which deliver from 9.00am to 6pm within mainland UK.

Free Delivery for orders over £99 excludes Royal Mail Special Delivery Services and timed next day delivery services by DPD or DHL.

 

Special Delivery UK - Guaranteed Next Working Day

We have 99.9% of the UK covered With Royal Mail Next Day Special Delivery. We guarantee delivery to most UK addresses by 1pm the next working day. This includes Northern Ireland, Jersey and Guernsey. Some places take longer to deliver to but we still guarantee delivery within three working days by 5.30 PM.

For the Next Day Special Delivery service, orders must be received by Future Shop by 4.30pm weekdays. Orders after the 4.30pm deadline cannot be guaranteed for same day dispatch.

Please note, Royal Mail Special Delivery for next working day may not be possible where non-standard cable lengths are ordered. If this is the case, the item will be shipped via The Royal Mail Special Delivery service as soon as the cable is custom made.

For orders weighing over 2KG, we reserve the right to ship items using Next Day Pre-Noon Courier Services where Royal Mail Special Delivery option has been selected.

 

Channel Islands & Northern Ireland

We accept orders from all Channel Islands including Alderney, Jersey, Guernsey and Sark. Unless you select a premium service, Items weighing under 2KG are delivered using our standard UK delivery option above. For items weighing over 2KG, a surcharge may be applied for all deliveries to the Channel Islands as well as Northern Ireland.

 

European Countries

Deliveries to EU member states are not subject to 20% VAT after December 31st 2020 and therefore the 20% VAT on items is automatically deducted when you log-in, register or proceed to place an order.

The customer will be liable for the VAT at the local VAT rate, duty on the import and the brokerage service fee if applicable. This may need to be paid in advance to your local Customs & Excise office or the delivery company before your order can be delivered.

We offer the following shipping services:

  • Royal Mail First Class International Airmail Services - Items are usually delivered within 3 to 5 working days.
  • Royal Mail Standard International Mail Services - Items are usually delivered within 7-10 working days.
  • DHL Express International - Items are usually delivered within 24 to 48 hours. DHL orders must be received by 3:30pm for next day service to most destinations in Europe
  • Federal Express International Priority - Items are usually delivered within 24 to 48 hours. FedEx orders must be received by 3.00pm for next day service to most destinations in Europe.
  • Federal Express International Economy - Item are usually delivered within 48 to 72 hours.

We reserve the right to change your shipping method without notification if you select a method that we cannot use for your shipment (for instance, we cannot ship via postal services for items over 2 Kg to International destinations). If we need to change your shipping method, we will choose the least expensive shipping method for your order.

 

Worldwide - Excluding UK & Europe

Deliveries outside of the UK are not subject to 20% VAT and so the 20% tax on items is automatically deducted when you log-in, register or proceed to place an order.

If applicable, the customer will be liable for the taxes at the local tax rate, duty on the import and the brokerage service fee. This may need to be paid in advance to your local Customs & Excise office or the delivery company before your order can be delivered.

We offer the following shipping services:

  • Royal Mail First Class International Airmail Services - Items are usually delivered within 7 to 10 working days.
  • Royal Mail Standard International Mail Services - Items are usually delivered within 15 working days.
  • DHL Express International - Items are usually delivered within 24 to 48 hours. DHL orders must be received by 3:30pm for next day service to most destinations in Europe
  • Federal Express International Priority - Items are usually delivered within 48 hours. FedEx orders must be received by 3.00pm in order to ship items the same day, subject to stock availability.

  • Where the actual weight of the package significantly exceeds the shipping cost charged on orders, we may write to you for an additional shipping charge. For larger orders, items may be shipped in multiple packets at our discretion.

We reserve the right to change your shipping method without notification if you select a method that we cannot use for your shipment (for instance, we cannot ship via postal services for items over 2 Kg to International destinations). If we need to change your shipping method, we will choose the least expensive shipping method for your order.

Write Your Own Review

Quantum Science Audio (QSA) Yellow Entry Level Slow-Blow Fuse

We are interested in your opinion of this product. let us and other customers know how you feel by filling in the comment field below. Your review will appear in this section within 3 working days.

Please do:

  • - Write 50-300 words for the product
  • - Comment on the products value and effectiveness
  • - Tell us if you like the product, but most importantly explain why you like or dislike it
  • - Mention related products and how this one rates by comparison
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AJM ✓ Verified Purchase
Incremental improvements when used in power supply chain 21 December 2025
I have bought several of the QSA yellow fuses from Futureshop. I have found that there is an incremental improvement in the sound each time a Yellow fuse is used, and that using multiple fuses in series in the power supply chain improves the sound for each Yellow fuse swapped in. I have also found further improvements when a Yellow power supply wall plate is used in the power supply chain in addition to the Yellow fuses.

As other reviewers have noted, the net improvement I feel is significant value given the outlay, and these fuses represent very good value for money. A period of burn-in does seem to improve performance. Highly recommended.
PR ✓ Verified Purchase
Significant system upgrade 4 September 2025
Following my ‘jaw-dropping’ experience after fitting QSA Yellow and Violet 13amp fuses to my mains plugs and after reading about the fuses' aim to reduce 'bottlenecking', it seemed logical to replace the internal slow blow fuses in the two power supplies feeding my CD Transport and Streamer. Again, the improvement in detail is remarkable, resulting in a stunning soundstage. Combined, these fuses have significantly upgraded my system and, therefore, my entire CD collection. As such, a remarkable value-for-money upgrade.

The fuses do need a considerable ‘burn-in’ period, to be at their best but the wait is well worth it.
Petar Petrov ✓ Verified Purchase
QSA Yellow - this is the best fuse for me 3 June 2025
QSA make the sound most natural, but you have to buy a yellow fuse as a minimum.
Richard M ✓ Verified Purchase
Definitely worth the investment. 21 March 2025
So power upgrades make no difference? Here’s a few comments I received:

1. “The supply is AC, so the directionality of a fuse is irrelevant.”
2. From the US supplier of my DAC and amp: “Please don’t spend $$$ on aftermarket fuses; they will make no difference”
I was sceptical too. Having got to what may be my end game system I thought nevertheless it might be worth trying power upgrades with the reassurance of Futureshop’s excellent return policy - basically nothing to lose. Well I started with power cables and was surprised at the level of improvement and then thought of trying fuses, starting with a single yellow mains fuse.

To cut a long story short, I ended up investing heavily in cables and mains fuses, mainly QSA Yellow plus some Violets, but I bought one at a time, only moving forward if there was worthwhile improvement. Having upgraded mains input I thought it would be worth trying an internal fuse: obviously more risky because, unlike mains fuses they can’t be swapped around. This is my first internal fuse, for a headphone amp, and there was a real improvement after only 10 hours burn in so I’m very pleased. This is how I’d summarise:

1. The improvement comes in soundstage imaging, naturalness and clarity. I don’t mean a perception of clarity from enhanced treble but an insight from lack of noise or smearing.
2. The level of improvement from the fuse is greater £ for £ than the mains cable upgrade. This surprised me.
3. Value? With a fuse change costing maybe 10% of the cost of a component (I have some Yellow, some Violet), I would honestly say the improvement is at component upgrade level, so on that basis, it is excellent value for money. With the return policy, I would return something if it wasn’t.
4. OK so instant A/B comparison is not possible but the differences are unmistakable.
5. There is a difference in the sound with direction, mainly in the bass.
AJM ✓ Verified Purchase
significant improvement in stereo imaging 28 February 2025
I found a significant improvement in stereo imaging.
B ✓ Verified Purchase
Good product 21 January 2024
It was recommended that I try some aftermarket fuses for my Nagra equipment, and I have to report that the result is not insignificant.

It was well worth the investment, and I would recommend anybody with a good system to give it a try to improve the "weakest" link.
Josh ✓ Verified Purchase
Interesting 26 July 2023
Using QSA yellow fuse in my headphone amp. The sharpness is not as good as other fuses that I owned. But it also creates a complete soundstage which is more than just a two-channel system.
Peter Szajko ✓ Verified Purchase
Sound is amazing 21 April 2023
The sound is amazing. I can’t wait to receive the Orange fuses.
Improvement in the entire frequeny range when fully burned in ✓ Verified Purchase
Wonky start but great end result 5 April 2023
When you first swap these out, you notice increased soundstage, depth and bass quantity.

For my setup, as soon as it hit the 10-hour burn-in mark, the bass quantity dropped until it hit around 80 hours which is when it started to come back.

The tonality is quite wonky through the weird parts of the burn-in. But the closer it gets to the end, the more consistent it gets.

Great value for money. I highly recommend it and can confirm that it blatantly lowers the noise floor.

Drums haven’t had a sense of realism on my setup, even with power cable and interconnect upgrades! When these were implemented, it started to get to that level of dynamics.
karan gupta ✓ Verified Purchase
Worth it and more 8 June 2022
I didn’t want to think a fuse could matter, but this was a significant improvement in my system.

Highly recommended, and now I have to go through all my fuses!!

Frequently Asked Questions

The Master Fuse is Synergistic Research’s most advanced design, engineered for maximum resolution, dynamics, and soundstage depth. The Purple Fuse, while more affordable, offers excellent performance and long-lasting reliability. Both elevate your system, but the Master Fuse sets the highest benchmark in the range.
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Yes. Synergistic Research fuses (including the Master, Purple, Pink, Orange, and Blue) are directional. For best results, install them so electricity flows left to right when viewing the fuse label. Many listeners report subtle sonic differences when reversed, especially after the fuse has been broken in.
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Yes. For example, Synergistic Research Black fuses typically require around 200 hours of break-in, with about 90% of tonal change settling after 100 hours. Patience is rewarded, as long-term listening reveals deeper improvements in tonal balance, staging, and overall clarity.
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Hi-fi fuses are safe to use when they are the correct rating and type specified by the manufacturer. They function in the same protective way as standard fuses, but can use different materials, construction methods and optimisations. Some listeners report improvements in clarity, focus, and low-level detail after fitting a hi-fi fuse. These changes are typically subtle and system-dependent, making fuses more of a fine-tuning option than a primary upgrade.
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We have tried and tested various different fuses from multiple 3rd party manufacturers, as well as the standard off the shelf fuses, and we believe that audiophile fuses do offer improvements while maintaining safety standards. Like any fuse, audiophile fuses will still blow above their rated amperage to protect your power connections & equipment. We understand that it seems counter-intuitive for a fuse to make improvements, however, we, along with many other audiophiles, have found that there are improvements to be found when swapping out an off the shelf fuse for an audiophile fuse. We highly recommend trialing an audiophile fuse in your system to hear the difference yourself.
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Many users report improvements in clarity, dynamics, and noise floor when using high‑quality audio fuses.
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They are usually fitted in Uk 3 Pin plugs, IEC inlets, or internal fuse holders within audio equipment.
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Some manufacturers recommend a short running‑in period for best performance.
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Enhance Your Experience: Free Cable Burn-In Service with Nordost VIDAR Machine

 

Please take note of the following details regarding our cable burn-in service:

  • Cable Compatibility: We regret to inform you that we cannot burn-in cables with stripped bare ends or BFA plugs. In order for cables to undergo the burn-in process, they should be terminated or have connectors.
  • Timing: Cables will be burnt in for the selected period after processing your order. For custom-length cables, the burn-in process will occur after they have been terminated by the manufacturer or our engineers unless specified otherwise in the product description.
  • Availability: Future Shop provides our cable burn-in service free of charge, but its availability is at our discretion. While we strive to fulfil all burn-in requests for the specified time periods, please understand that during exceptionally busy periods, we may be unable to meet the demand due to limited connections on the Nordost Vidar cable conditioning machines.

The Nordost VIDAR cable burn-in machine integrates three key functions into one operation:

  1. Charge Neutralisation: It eliminates charges that accumulate around the cables and their insulation, ensuring a more balanced electrical environment.
  2. Deep Conditioning: The machine provides a wide band and deep conditioning process that affects the conductor core, resulting in changes to the signal transmission through the metal. This deep conditioning enhances the cable's performance.
  3. Ultrasonic Surface Conditioning: The VIDAR machine utilizes ultrasonic waves to condition the surface of the conductors, optimizing their contact and overall conductivity.

The VIDAR employs a proprietary combination of composite and complex signals to condition the cables. These signals comprise ultra-low and ultra-high frequencies, extending beyond the range of video frequencies. The signal moves back and forth along the cable, penetrating deep into the core with ultra-low frequencies and traversing the surface with ultra-high frequencies. This transmission method generates beat harmonics between the two complex waveforms, which permeate all layers of the cable. The circuitry of the VIDAR also drives electrons from the conductor into the insulation area, neutralizing electrical charges.

 

 

Nordost Vidar Burn-in Machine

 

 

So, what does this all mean for you?

The ultimate outcome of conditioning cables with the Nordost VIDAR is improved sound staging, increased detail, and an overall more musical presentation in your audio system.

Now, you may wonder why cable burn-in is necessary. During cable manufacturing, gasses become trapped as insulation is applied over the conductors. Additionally, new cables often possess high electrical charges, resulting in a brittle and bright sound that lacks the desired detail and depth for music production.

When cables undergo burn-in, the trapped gasses are dissipated, and small impurities in the conductor metals begin to exhibit diode-like behaviour, favouring current flow in a specific direction.

Here are the physical effects of the burn-in process:

  • Charge Neutralisation: The burn-in process neutralizes charges in the conductors and insulation, promoting a more balanced electrical environment.
  • Wide Bandwidth Frequencies: The conditioning affects how signals pass through the metal, enabling a wider range of frequencies to penetrate all cable layers.
  • Signal Transmission: The burn-in process establishes the directionality of the cable, optimizing signal transmission from one end to the other.

When cables are properly burnt in, you can expect the following audible changes in your audio system:

  • Fuller and Natural Sound: Your system should be capable of producing a more immersive and realistic performance with a fuller and more natural sound.
  • Increased Detail: You may notice enhanced details and nuances in the music, allowing you to perceive subtle elements that were previously hidden.
  • Improved Soundstage: The dimensionality of your system's soundstage can be greatly improved, creating a more spacious and immersive listening experience.

At Future Shop, our goal is to maximise your satisfaction. That's why we offer a free burn-in service on all our cables before they arrive at your door, enabling you to sit back and enjoy the benefits of properly conditioned cables in your audio system.

 

 


Download Icon  READ MORE ABOUT THE NORDOST VIDAR CABLE TREATMENT

 

Write Your Own Review

Quantum Science Audio (QSA) Yellow Entry Level Slow-Blow Fuse

We are interested in your opinion of this product. let us and other customers know how you feel by filling in the comment field below. Your review will appear in this section within 3 working days.

Please do:

  • - Write 50-300 words for the product
  • - Comment on the products value and effectiveness
  • - Tell us if you like the product, but most importantly explain why you like or dislike it
  • - Mention related products and how this one rates by comparison
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