I did a review at PFO on the Iso clean and still feel my comments were accurate. I have backed off the suggestion of adding silver paste to electrical connections, now prefer clean connection and no additives except (maybe) Caig Pro Gold.
In my system, the change from stock fuses to Isoclean fuses was absolutely positive. The Isoclean mostly reduced distortion and grunge while tightening up imaging and improving the sense of placement. This kind of upgrade is so right that you accept the change as part of the music within a few minutes. It's very much like the benefit offered by a fine aftermarket power cord, but in miniature.
In my listening evaluation, the Isoclean fuses were installed into the holders on the back panel of each Aesthetix power supply. The Improvement was obvious from the moment the system was turned on. Better still, everything continued to improve for several days as the fuses settled in.
There is something I should point out here about installing Isoclean fuses. Each fuse is marked with an arrow, indicating the direction the current should flow. Take care to not reverse these, as it harms the sound.
I might also add the best fuse is no fuse. People who've modded maggies and taken out the fuse on the ribbon have been amazed by just how good Jim's ribbon design is! (of course one had to have adequate protection elsewhere to do this.)
While I appreciate the humor, one should give them a listen before dismissing out of hand
I'm sure many of us have spent more on accessories that clearly didn't walk the walk eg. cables, AC line conditioners, room treatment, etc. Also, in the scheme of things, $50 for an sizable sonic upgrade isn't a whole lot of money considering the investment many of us have in our equipment.
I spent a few minutes reading the data. It was kind of hard as it seems to be some kind of scanned document with European nomenclature (e.g. comma used instead of decimal point).
At high level, I was surprised by the level of precision they used to measure resistance. Typical ohmmeters we use is usually accurate to 0.1 ohm. Anything more than that and you start to measure the resistance of the probe wire and resistance between the probe and what you are measuring. The measurements they have is in *milli* ohm or one thousands of an ohm. So the best one measures 0.044 ohms and the worst, 0.155 ohms. What is surprising is that they then take this to two more decimal places. So the first value is listed as 0.04447! I have no idea how one can measure something this repeatedly. I suspect changing temps, or just remeasuring would result in wildly different values to say nothing of what strict process must be used to attach the measurement device to DUT (device under test).
Later, they go to even three decimal places after the mOhm value. Unless I am reading these numbers wrong, I can't fathom how they do this without at least specifying why their test methodology is right.
As far as directionality, they explain why there could be a difference in construction but not why the device would measure differently. Again, I would have loved to see data on how repeatable their results are.
That said, there are two points on the other side:
1. They are right about soldering fuses being better than using sockets. The sockets invariably become lose, causing large resistance and random failures.
2. I have seen fuse elements go back and forth as the music plays in some amps! So clearly there can be issues with fuses that are rated for low amps.
So the notion of high quality fuse may be right but I personally am not moved by their measurements without more data.
We have experimented with the Hi-Fi Tuning and Isoclean fuses in some equipment. Some equipment improved and some got worse. I believe that I now have 7 Isoclean fuses in my upgraded (modified) Onkyo PR-SC885 Pre/Pro that definitely has improved the performance of the unit.
...And there is good reason for skepticism in this case.
Power Supply Fuse: For an amp using 1kW from a 120v supply that is less than 1A going through the fuse. My amp uses a 10A fuse in this position which has a nominal resistance of less than 0.04 ohms for a power dissipation of less than 40 milliwatts. The voltage drop is 40 milliVolts. The amp runs mainly Class A but let's just say it went crazy and ran in Class B so that would give a power demand swing of 250 Watt, a corresponding current swing of 0.25 Amps, swing across the fuse of 10 milliVolts and a power swing across the fuse of less than 10 milliwatts.
B+ Rail Fuse: My amp uses 1A fuses here which have a resistance (by measurement) of about 0.2 ohms. B+ is about 600V. The DC impedance of the output transformer primary is about 300 ohms which is in series with the fuse. The added loss due to the fuse is less than 1% and it is a constant. The AC resistance of the primary is 1500 ohms. Fuse's contribution to this is even more nada.
Although the paper reference above mentions frequency-dependent impedance measurements it neglects to present them in the paper. My experience is there is no significant frequency dependence at audio-related frequencies.
I suggest that anyone with a high-end stereo system, using good quality parts, who is experiencing sound changes associated with different fuses should have it serviced by a qualified electrician.
Since I am not an EE and have not tried audiophile fuses in my system, I thought i would take a look at what the good folks at PS Audio had to say about the audiophile fuses.
"Critical Link fuses are built to replace the stock fuse inside your equipment to enhance performance.
While small in physical size these are, as their name implies, Critical Links in the AV chain.
Every aspect of your AC power chain, from the start of the AC power until the music reaches your ears is a critical link that has a direct impact on the performance you enjoy.
The engineering team at PS Audio advocates building a strong AC power foundation and the Critical Link fuses are a key element in that power foundation. Much of the foundation is built around the wall receptacle and the cleaning and regeneration of pure AC that feeds our equipment. But no less important is the power path into our products.
If you view the AC power chain in the same way you might think of water flowing through a hose, then it is easy to imagine how the flow can only be as strong as the weakest link in the chain. In the case of a piece of stereo equipment, the weakest link in the chain happens to be the fuse.
A fuse is built around a very small piece of wire designed to melt in case too much current flows through it, thus protecting the equipment from overload. All the power your equipment consumes must pass through this tiny restricted wire.
It is ironic that we can pay so much attention to perfecting our power cables and delivery systems while ignoring these small electrical impediments called fuses.
What’s different about a Critical Link fuse?
A standard stock fuse is built with little concern for high-end audio video applications. In fact, fuses haven’t changed much from their introduction by American inventor Thomas Edison over 100 years ago.
Fuses are typically built with glass bodies, tin end caps and low grade conductor material inside. They are prone to vibrations, voltage drop across the conductor and are the cause of a surprisingly audible negative impact on our equipment.
Critical Link fuses are built entirely different. The end caps of a Critical Link fuse are machined out of OFC copper rather than tin.
The all important conductor is also made from OFC copper and welded to the end caps.
Because vibrations are damaging to sonics, the inside of the Critical Link fuse is filled with in a Polyolefin tube foam damping material and the outside shell of the fuse is built from a non-resonant ceramic material.
When the Critical Link fuse is finished, it is sent to a -196ºC cryogenic immersion bath which improves conductivity even further.
So, once you replace your fuse what can you expect to hear? Your whole system will sound better, faster and more accurate across the line. Dynamics improve, transients sound quicker with greater energy and inter-note separation improves as well. For instance, a plucked string instrument will have greater snap and realism without sacrificing definition. The improvements are very audible almost immediately.
Due to the consumable nature of fuses no warranty is available nor does the 30 day in home trial apply."
Humph. I'll just note that -196 degC is liquid nitrogen temperature; if they were really interested in good sound, they'd use liquid helium to get a much lower cryogenic temperature (about -269 degC, just 4 degrees above absolute zero). I honestly have never thought about the negative impact power-line fuse vibrations have upon my system... I have used ceramic-encased fuses, but as required for flame resistance, not for their anti-vibration properties. I would try them, but $60 buys a lot of CDs. I am curious to see what benefits a controlled listening test will reveal, however.
Back to the techie threads - Don "the geek"
p.s. In the primordial past I measured the impact of various fuses, or no fuse, on the performance of speakers and was able to measure differences. They were slight, but there. However, after blowing the tweeters in a pair of good speakers, my boss decided that the sonic loss was much less than the cost of new tweeters...