The new Synergistic Research BLUE fuses ....

A hypothetical question---no snarkiness intended---for those who have heard a significant improvement in sound by installing an "audiophile" fuse in place of a garden variety one: For the absolute best sound possible, it makes sense to consider the possibility that the altogether elimination of a fuse may be expected to result in sound superior to even the best "sounding" fuse (parenthesis for the benefit of those who don’t cotton to such a notion). When I had Ric Schultz "modify" (if you know Ric, you know his mods are far more than mere "mods" ;-) my Audible Illusions Modulus 2 pre-amp, I was given the choice of having the fuse removed from the pre-amp. Being young(er) and opposed to compromise, I elected to have Ric remove it. In the promotional literature for his mod, Ric stated removing the fuse would enable the pre to provide slightly improved sound quality. Having heard the modified Modulus only with the fuse removed, I can’t testify to the truth of that claim.

So my question is: Audiophile-grade fuse enthusiasts are obviously very serious about doing whatever is possible to squeeze the maximum potential out of their gear. Does that include throwing caution to the wind by removing the fuses from their electronics? ARC tube power amp owners know (or should know) that the company made the engineering choice to not fuse their output tubes, as they feel fuses in those locations compromise the sound quality of their amps. The penalty for doing so is damage to the amp in the (inevitable) case of a tube going bad. Are there any audiophile fuse proponents willing to go "all the way"?

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February 29, 2016 by Paul McGowan

Here’s a subject that simply drives some people nuts. Fuses.

Change the power fuse in a DAC or preamp and the sound changes, depending on the type of fuse you change to.

I first became aware of fuses and their sonic differences in the 1980s. We were working on releasing the 200C power amplifier, designed by Bob Odell. This 200 watt per channel amplifier was the best sounding power amplifier we had ever produced and we labored long and hard polishing every part and decision to perfection. In those days we relied upon an output fuse to protect the loudspeaker and the amp from each other. Too much current passes through the amp and the fuse blows, disconnecting the power amp’s output.

The prototype amplifiers didn’t have output fuses. It wasn’t until we got to the production versions that we added them, and that’s when the trouble started. The production amplifier didn’t sound as good as the prototype: thinner, weaker, with less bloom and midbass strength, relative to the prototype. Why the two sounded so different was a real head scratcher.

When faced with such differences, you start removing any changes between the two until they sound the same. It didn’t take long before we discovered it was the damn output fuse.  Short it with a clip lead and the fullness of the music returned.

This vexed us greatly because we wanted the sound of no fuse while enjoying the benefits of its protection. Different types of fuses sounded differently too. We gold plated the fuse and its holder to see if that would help. It did. But not a lot. We even tried bypassing it with a small capacitor. That helped to, but wasn’t a good idea. And neither solved the problem.

In the end we came up with a clever scheme. We took the feedback for the amplifier not from the amplifier’s output, but from the output of the fuse. Thus, the fuse was included in the amplifier’s corrective feedback loop, and the fullness returned to the music. (For those of you giving this some thought, we also added a 100Ω resistor in parallel with the fuse so if the fuse blew the amp would remain stable).

With the clarity of hindsight there are many explanations of why this mattered, damping factor changes not the least of them.

The point of the story is simple. Fuses matter. But why should they matter in the AC circuit? I don’t have a great answer handy. But we’ll look some more tomorrow.