Reviews for Quantum Science Audio (QSA) Yellow Entry Level UK Mains Fuse - 3A, 5A & 13 Amp

This is my second QSA yellow fuse. The first fuse I bought went in my Wireworld Matrix 2 and gave me an excellent performance. This new fuse went in my NRG-X2 cable to my Technics system via the mains, which seems a lot better. It provides a richer, cleaner sound and more detailed bass. It sounds more neutral and has a better soundstage.

I also had this fuse burn in for 96 hours, and, wow, I've been told it needs 200 hours to burn in properly.

I have left more detailed reviews of this fantastic little fuse, but the best endorsement I can give is that, so far, I have purchased four Yellow and one Violet fuse, plus another Yellow on order. I also listened to Hifi Tuning Supreme, Supreme Diamond, and SR Purple, and these QSA fuses, whilst improving every metric, were more “natural” to my ears.

Give one a try and move it between components to gauge where it improves the most—it does vary, but I guarantee you will want more.

I first plugged this in an Audioquest cable to my Naim Nap300 and noticed a decent improvement in clarity, good enough to be pleased with the cost outlay. A few days later I switched it to a Chord power cable into my Chord S6 power block. This has the plugs for my Naim Nac252 and sources; the improvement was even greater.

There is no warming or changing the sound, no shift in highs, mids, or lows, but instead a significant increase in precision, detail, and clarity of sounds.

Amazing. Now, I'm putting another back in the power amp, too.

From initial scepticism to trying one, I now have a number of these fuses and can confirm they are definitely a worthwhile upgrade. The improvement is relatively much greater than the cost of the fuse so, on this basis, they are excellent value.

They make the sound more “natural”, and there is a palpable increase in clarity. As mentioned, I started off with one to assess its benefit, and the effectiveness does vary with different components, so it is worth auditioning across your system.

In summary, I would recommend trying one and auditioning the benefits in different parts of your system and I am sure you will want to buy more fuses.

I can wholeheartedly recommend QSA fuses. I started with one Yellow to hear for myself, tried it in a number of components and have been so impressed with the level of improvement relative to cost (equivalent IMO to a £650 set of interconnects or power cable!) that I will roll them out one at a time across my system, checking improvement each time.

I also have one Violet, which is even better, but having already invested heavily in power upgrades, the Yellow is a cost sweet spot for me.

Fundamentally, detail, coherence, timbre, and listening pleasure improve. They do need time to bed in and continue to improve.

Having sceptically dipped my toe into the waters of fuses, I am now convinced, and this is my second.

This yellow fuse, without a doubt (to my ears), improves the soundstage, naturalness, and dynamics. How dramatic the effect is varies with different components. For example, there is a marked improvement with my sources and reasonable improvement with my headphone amp, but a lesser improvement with my power amps, probably because they already have excellent power regulation.

Absolutely worth auditioning because the improvement on the right component is excellent value.

I finally sorted out my system and interconnects and was happy with everything.

I was massively sceptical about power upgrades but thought it was worth a dabble to see if there would be any incremental gains, so starting with power cables, I found surprising gains. Then fuses came into the frame with even greater scepticism, and I dabbled with cheaper fuses from another company, which justified my scepticism by making my ears clench.

Following some excellent input from Mark at Futureshop, I was persuaded to try this QSA Yellow with 96 hrs burn-in. My ears have certainly been unclenched, and I have been surprised by the improvement.

Most of my plugs are Furutech, so it’s a faff to change fuses around, but I have one plug with a fuse cassette that powers a streamer, and this yellow fuse has removed any hint of digital glare. Plus, the sound is natural and engaging, with increased clarity and soundstage without changing the character of my system. So, I’m convinced that other fuses are on order, and I’m looking forward to auditioning for analogue components in particular.

I recommend trying this fuse, particularly if you’re generally happy with your system because there are real gains to be had.

I put this in my WireWorld Matrix 2, and what a massive difference.

This feeds my Blue & Black QSA fuses in my system, making the sound and picture exceptionally good.

After buying a very good QSA Light Blue fuse, I decided to go with this QSA Yellow.

I used this fuse for my Wireworld Matrix 2 strip and was blown over by how much more quality it gave me.

Even more clarity in the bass, and improved my C1OLED TV picture quality. But the sound on my hifi is so much sharper and clearer. This fuse is unbelievably good.

I'd had the QSA Light Blue (QLB) 13A fuse for around ten days (and have already submitted a review for it—check that out if you have a mind to) when I decided to buy the QSA Yellow (QY) earlier than I'd planned because I was so impressed with the former.

I've possibly not yet fully broken in the QSA Yellow (nor even the QSA Light Blue), but I can confirm that it sounds better already. The QSA Light Blue was previously in one of the £25 MRCU ready-wired mains cables used for my Acoustic Invader preamplifier. It sounded better there than with my Gustard R26 DAC. Incidentally, I've found the two fuses to work better for me in the "wrong" direction in my MRCU mains plugs.

At first, I simply tried the QSA Yelow alone for my preamp. Next, I simultaneously tried both the QSA Yellow (for my preamp) and the QSA Light Blue (for my DAC) and vice versa. Surprisingly, both combinations sounded worse than with the QSA Yeelow alone. Hence, I have subsequently moved the QSA Light Blue to the mains cable for the integrated amp (an Audiolab 6000A) I use in my second near-field system. It gives a noticeable improvement there, too -- so I haven't wasted my money on it.

I've no real idea why a (singular) QSA fuse makes a difference, but my ears tell me it does. If you're anything like me, you too may have noticed that your (untreated) system sounds 100% at its best *only occasionally* (mood? weather?). Most of the time, it sounds at only around 70-80%.

When I used a QSA Light Blue, it not only improved the sound to around 130% but, in my opinion -- more importantly -- did so *reliably and consistently*.

As for the QSA Yellow, I'd put the improvement (so far) on the same subjective scale at around 150%. I probably won't be spending three times as much as the QSA Yellow on the QSA Violet (£620) -- diminishing returns seem quite possible, and in any case, I'm more than satisfied with what I've got.

What are the perceived sound improvements through the Decware ZF15M open baffle clones used in my primary system?

. Better and more holographic soundstage
. Better dynamics
. More easily discernible instrumental/vocal threads
. Better tonality/timbre
. Increased subtlety and refinement
. Noticeably greater emotional engagement. I've been playing tracks that I'd tended to skip more often. The QSA fuses seem to have breathed new life into them.

I'd summarise by saying that the return on investment for both fuses far exceeds what I've obtained from other system tweaks I've introduced in the past. If, as I am, you are the cautious type, you might consider dipping your toes into the weird and wonderful world of fuses with the £86 QLB as I did -- maybe even with the £50 QSA Black. One could easily spend as much on equipment supports for a smaller effect. I've found I don't have to strain to hear the improvements -- they're obvious from the start and get better as the fuse beds in.