jerryg123

Fuse standards are not UL. Safety standards are set forth by the N.E.C. in the US ...

You are mistaken - UL most certainly sets standards and issues certifications for fuses. Some info specifically referring to fuses and fuseholders is here on its website:

" ... We can simultaneously provide Global Market Access solutions for the UL Mark in North America, as well as other certifications for markets around the world ... "

OK, so I finally (hesitatingly) just recently jumped on the audiophile fuse bandwagon. It’s my first time, even though I’ve been reading about them for years now. I just purchased two HiFi Tuning Silverstar series fuses, but have yet to install them. I realize the models I purchased are not the most expensive on the market, but it’s a first step.

What doesn’t sit well with me regarding these audiophile fuse ratings is the fact that some audiophiles, due to some audiophile fuses prematurely or mistakenly opening up (popping or blowing - whatever word you want to use) in equipment (from what I’ve read in this thread and on other message boards), may need to increase replacement fuse amperage ratings when replacing them.

IMO there shouldn’t be two different amperage ratings standards - one for standard non-audiophile fuses, and one for audiophile fuses. If my HiFi Tuning fuses blow on me, they will not be replaced with higher amperage rated audiophile fuses. It’ll simply be lesson learned.

I get the feeling that some of these audiophile fuse makers haven’t been in the business of making fuses long enough to have figured it out, or maybe haven’t done their due diligence research (as well known companies like Bussmann or Littelfuse have done), if they’re simply recommending increasing amperage ratings (other than what is spec’d by the equipment manufacturer) when replacing blown audiophile fuses.

Just in case you’re interested, I’d like to tell you a little bit more of my above situation. I’ve been in radio broadcast engineering for decades now, and have dealt with many "professional" manufacturer’s products over the years. I also consider myself an audio-enthusiast, and love music, and have always loved music (and audio in general). No, I don’t own $10,000 amplifiers, or $50,000 speakers, but I think I do know audio pretty well, and what makes an audio system sound great (low noise floors, eradicating hums & buzzes, flat frequency response’s, amplifier damping factors, the right acoustics, clean AC power, of course the list goes on and on). I think my ears are also still communicating pretty well these days with my brain, with *very little* Tinnitus, even after decades of attending loud concerts, and patronizing loud dance clubs (I always have rested my ears in super quiet spaces, after being in extremely loud environments).

My home system is not your typical audiophile type setup, but I treat it as one. In radio, we need to send one source to many different locations, and to do that, we utilize what is called a distribution amp (DA). In the radio days of analog, we used analog DA’s. These days most radio stations are 95% digital, so the DA’s are now digital too. My home environment is still about 95% analog, and that doesn’t bother me one bit (Ha, I think there’s a pun there).

In radio, since equipment is typically powered up 24-7-365, and lightning is striking your broadcast towers throughout the year(s), you get a pretty good indication of what the workhorses are, and which are not. Over the years I have found that the Audioarts 8400 DA is definitely a workhorse, while providing, IMO, incredible audio performance at the same time. I employ two of these devices in my home system in parallel. That provides me 1 stereo analog balanced input, resulting in 16 stereo balanced outputs.

I have one main source system (turntables, CD players, computer soundcard - my streamer, cassette deck, etc.), which via DA’s, feeds other amplifier and speaker systems in my house. The DA’s are mainly balanced analog devices, utilizing NE5532 op-amps (all original Phillips brand in mine). These DA’s allow my mixer output (which handles mixing for the above sources), to be fed to 16 devices (currently using only 13 of the 16 outputs). I can send that high quality mixer feed to other amplifiers in my house or garage, in balanced analog mode.

So you see the Audioart’s DA’s are really the heart of my system. This is where I inserted the HiFi Tuning fuses (1 fuse in each DA). Since these DA’s have been powered up non-stop for over 21 years now, I thought it was time to also replace the 470uf 63v power supply filter capacitors in them (2 in each unit), even though the current ones were showing no sign, at all (that I could hear), of needing replacing. Since there’s about 10 stereo cables connected to each DA, which need to be labeled and unplugged first, I only wanted to tackle this job once. So with parts in hand...

I don’t know if I’ve opened my particular personal DA’s before (I have with other Audioarts DA’s at other radio stations), but when I did, I didn’t find any heat fatigue at all, from the voltage regulators, or op-amp sockets. After 21 years of constantly being powered up, I was very impressed by that. The nichicon power supply filter caps were not buldging in any way whatsoever, and showed no visual sign of needing replacing. Maybe that is due to the space I allow the DA’s to breathe (1 open rack space above and below in the rack), or because the DA’s have been immaculately designed right from the start (which I know they have).

So after replacing the power supply filter caps (with Vishay’s - which even though they have the exact ratings as the nichicon’s, are now physically larger), installing the HiFi Tuning Silverstar fuses (315 mA slo blow), and lifting and re-seating all 18 NE5532 chips in each DA, I’m pretty sure I don’t hear much difference in sound at all, compared to the former components, and to tell you the truth, I really didn’t expect to hear any. To me, these DA’s have always sounded like a wire with no gain, in other words, these DA’s sound like they are invisible to my ears, and that’s exactly the way I want them to sound.

As you can see, utilizing 315 mA fuses, these DA’s use very little current, even when driving all 8 stereo outputs. All of the DA outputs are set at unity gain, so really these DA’s are barely working at all. Not that I needed to, but I also used a Variac, and brought the voltage up slowly when firing these DA’s back up, with the new caps in them. The HiFi Tuning fuses did not blow.

Audioarts’ 8400 Distribution Amplifier

The hot end is the forward end of the fuse which as you say goes straight in to the power supply.

How does that work with it being AC?