When you think about it, the notion that a fuse can make a difference is not that implausible. If, as most designers of high-end audio electronics will admit, the kind of wire used for a component's internal wiring can make a difference, then why not a fuse? After all, the job of the fuse is to melt when a certain level of current is reached, so might there not be differences in how various fuses react to current at lower levels, possibly constricting or otherwise influencing the power used by the component? The HiFi-Tuning fuses use pure silver wiring, gold-over-silver endcaps, and ceramic rather than glass casings for better resonance characteristics. But a plausible mechanism of action and the use of high-quality materials are one thing; audible improvements are something else.
My first test involved the PS Audio GCC-100 integrated amp, a product I hold in very high regard; if its performance could be improved simply by replacing a fuse, that would be great. I talked to the PS Audio folks to find out what the GCC-100 uses in the way of a fuse, and was told that it uses two, both located on a circuit board, and that accessing them was a bit tricky. Before tackling the job, I unplugged the GCC-100's AC cord for a couple of hours to allow its capacitors to discharge, then removed the screws securing the chassis cover and gently lifted it a bit, looking for the wiring harness that would have to be unplugged before I could proceed. Once I'd located and unplugged the harness, replacing the fuses was pretty easy.
Before doing any of this, I spent some time listening to the GCC-100 to refresh my memory of what it sounds like. Yes, the tonal neutrality, resolution, transparency, and rhythmic thrust that had originally impressed me were still there. If the HiFi-Tuning fuses were to improve on this, they had their work cut out for them.
But improve the sound they did, and not just marginally. The PS Audio GCC-100 now sounded clearer, more dynamic, with improved transients—simply better all around. The difference was big enough that I didn't feel I had to go back and forth between fuses to convince myself that I was hearing it. But I did so anyway, if only to satisfy myself that what I was hearing was not the result of the mere act of replacing fuses, which to some degree can't help but serve to clean the contacts of fuse and fuse holder.
It wasn't. The improvement in sound was far out of proportion with the $60/pair cost of the HiFi-Tuning fuses. (Under its Critical Link label, PS Audio markets special fuses for its own products that are priced about the same as those from HiFi-Tuning. I briefly tried a pair of Critical Links in the GCC-100, and they, too, produced an improvement over the stock fuses.)
As I note in the main body of my Onkyo A-9555 review, the A-9555 benefited similarly from the use of the HiFi-Tuning fuses. As with every tweak, your mileage may vary, but the HiFi-Tuning fuses, available from www.ultrasystem.com, represent what I found to be a very worthwhile sonic improvement for a relatively small investment.—Robert Deutsch
Go Blow a Fuse, Michael Fremer, February 2007 (Vol.30 No.2):
When I was a poor audiophile, I loved tiny tweaks. Without switching out components, I could improve my system's sound without spending too much money. Bypassing or replacing cheap capacitors, cleaning connections, applying Star typewriter-cleaning gum to vibrating headshells, and other tiny tweaks made memorable sonic improvements.
I recently replaced the cheap fuses in my Musical Fidelity kWP preamplifier with fuses made by HiFi Tuning in Germany, sent to me by The Cable Company. These have silver filaments, ceramic bodies, and gold-over-silver terminations, and damn if they didn't seem to produce a subtle but noticeable improvement in smoothness and coherence. For less than $30 each (available in various sizes they're worth trying, if only for the diversionary entertainment.—Michael Fremer