Fuse sound quality


Ok, I’m in the dorm room of “the Experts”. So please clear this up for my little brain:
I have a power cable the size of a garden hose coming in. How can this little fuse with a little sliver of metal, affect sound quality?


My unscientific take is that it’s the point of entry to your device “the gate keeper” you want the best flow of power that’s possible.


Complete speculation on my part:
Since a fuse is inherently a non-linear device (e.g. it doesn’t react proportionally the same to small currents as it does to large currents) and it needs to be near the non-linear region to be an effective fuse, it modulates the current based on the current flowing thru it. Combine that with AC that isn’t symmetrical because of things like half wave rectification (which only draws power on one polarity of the AC waveform) and you end up with different differences with different fuses. Slow blow fuses add even more complexity to the situation.


We have discussed, debated, argued this many times without resolution.

I am a skeptic by nature and have trouble accepting a fuse is going to sound different than another fuse. I am particularly skeptical of the claim of fuse directionality in an AC circuit where, by definition, the current is flowing in both directions equally - the current flows both directions on both legs of the circuit every cycle. Directional implies the fuse is acting as a diode and restricts/filters current in one direction but not the other. Affecting one-half of the waveform differently than the other does not intuitively appear to be a good idea.

At least one fuse maker states his fuses are not directional until installed. The use makes them directional and you need to keep them installed the same way.

I find interesting that no one, at least to my knowledge, has opened a specialty fuse up and found anything other than a wire and some stuffing.

Perhaps expensive fuses ameliorate the negative impact of an inexpensive fuse.

One would expect the best sound would be no fuse, straight wire in eliminating the fuse holder and fuse entirely. I have compared a run of the mill fuse with a good quality jumper. I heard no appreciable difference when bypassing the fuse holder and fuse.Then again, perhaps a fancy fuse sounds better than straight wire; the fuse itself process the signal.

In conclusion, not yet being able to articulate an explanation does not mean a phenomenon does not exist. Many hear differences in fuses, including directionality.


I continue to find this a fascinatingly wonderful hypothesis. Fuses, by their very nature, are nearly in failure mode at all times.


Only a very small proportion of the current flowing into the device via the power cable actually flows through the internal fuse/s, right?


The only fuse I ever had blow was in a P10. Twice. Lucky it wasn’t one of those $50+ fuses. PS Audio must believe in them, they used to sell them. I have some.


I haven’t thought about why they sound different but for me the few different ones I’ve tried did, and one even more dramatically so depending on the direction.

I did not spend much, bought one SR Black used, and another Padis new but paid ~$35 from Germany. I believe they OEM for Furutech.

Anyway, both were an improvement in the BHK pre for me. I preferred the Padis over the SR. The SR sounded about the same both directions to me, the Padis was much more distinct.

I put it in and listened for just a few minutes, shutdown, flipped it and the soundstage opened up. I flipped it back and the stage shrank some, not WOW but some.

To put the change into perspective, if someone changed the fuse or flipped it and I didn’t know, would I be able to tell, probably not. It’s an inexpensive way to satisfy the need to tweak.

Alas my BHK has eaten both fuses so I’m back to the stock. Were they both not up to 2A spec or does the BHK draw more than it should at startup? I don’t know. Not worth fussing over, but I probably will get another Padis (eBay from Germany) sometime in the future.


Try VH Audio. Good prices and a nice guy to deal with.


You’re not the first to mention the BHK pre blowing fuses. Mine blew one but I’m sure it was my fault, plugging the cable into the back with the power switched on.
I went a couple months back with the stock fuse and just recently put in another Blue. No doubt it sounds better—enough to not feel too silly paying $149. for a fuse. Like so many things, it’s a happy mystery to me.


“Only a very small proportion of the current flowing into the device via the power cable actually flows through the internal fuse/s, right?”

I am not sure what you mean.
All the “current flowing into the device via the power cable” will flow through the main fuse or circuit breaker.


No, I don’t think it does.


This is an easy subject to misunderstand. You’re both right. All the voltage and current used in a device flows through the fuse. That’s for sure.

I think what Brodric means is that because the fuse is so tiny and without impedance, there’s no voltage drop across it, thus no current expended within it. Kind of like a zero Ohm resistor.

But the power definitely travels through it.


A fuse definitely has resistance, because you are relying upon resistive heating with current until, when overcurrent is reached, the heat can no longer be dissipated quickly enough and the fuse melts. The resistance increases as the fuse gets hotter. The fuse is thus a non-linear element, and not really anything you would want in a signal path unless it was absolutely necessary.


I am amazed at people that can hear these differences. Not to be a jerk but I would like to see some DBT on this. Power cords, yes. Power conditioners most certainly. Good interconnects etc. all add up to a lot imo. Fuse not so sure. Are PSA’s fuses even in the audio path? Often designs are not just for this reason. I do agree a nice jumper should be better but with my luck…


There was a change in fuse spec in the UK for 230/240 volt BHK amplifiers because at switch-on the inrush current could take out the fuse. I bought a packet of 5x20mm. T2AH250V TL Ceramic fuses at a cost of £1.50 ($2 US) for 10… My mate who is dedicated in the pursuit of audio perfection had told me changing to top spec fuses was a no brainer, huge improvement! Tom was horrified that I would sully my BHK300s with such cheap quality shit( his actual words ) Well, I noticed no degradation in sound quality…

When Tom goes on holiday with his wife I look in on his property and pick up his mail, etc. and he does the same for my wife and I…
Last summer when Tom was away from home I swapped his super expensive fuses on his BHK250 ( fuses on either side of the IEC socket ) with two fuses that cost 0.15 pence each…
On his return he was happy to be back listening to good quality music… I thought he might not notice any drop off in musicality (initially) after being away from his system for two weeks…‘but I was waiting on a reaction’ !

Well, 9 months later and just prior to my mate and his wife going to visit their daughter and family I produced the two expensive Audiophile Quality fuses and told him they would be settled down and sounding at their best on his return… He fired off a few profanities at me but we did see the funny side…

I am not saying that fuses don’t make a difference / improvement, because people do notice a difference but, any perceived difference wasn’t big enough for my mate Tom to notice over a 9 month period listening to his system with the cheaper priced fuses …!


I’m convinced that fuses can sound different although it’s the biggest mystery to me in my system.
I wish the guy with the yoooge brain would splain it. Of course, I’d have to read his reply 28 times to even begin to understand it but I’ d love to know.


Instead of a fuse(s) on an amplifiers power supply why not fit a circuit breaker ? Circuit breakers are very sensitive to fault conditions on the DC side of the power supply as well as the transformer primary winding. A 5A or 2A subminiature breaker in the HT line of a power amplifier will give safety in the event of an output stage fault. Depending on the type of circuit breaker used this also brings the added advantage of being an ON-OFF switch, thereby reducing the wiring and extra switch contacts that degrade performance by introducing extra impedance into the supply line. It would save money. And no need for any expensive super fuses !
Just a thought ?
But I dare say it would only lead to discussions about the best sounding subminiature breakers !


You are positively evil. :slight_smile: