PADIS vs Furutech fuses


I now have about 260 hours on my PADIS fuse and ready to some listening. The PADIS fuse appears to look exactly like the Furutech fuse. It has the same blue casing with the PF logo on one side. Actually, the only visible difference between the PADIS and Furutech is that the Furutech has “FURUTECH” printed on the opposite side. However, there are actually differences:

My very initial thoughts on the PADIS fuse (in the first few hours) was that the PADIS seemed somewhat dryer sounding than the Furutech. The PADIS did not have the typical “cold / wet /chimey” tones that fresh rhodium plated Furutech components generally have (I’ve tested Furutech rhodium fuses, power cord connectors, interconnect – they all initially contribute this cold/chime character).

I have often stated that Furutech rhodium is painful to burn in. I have burned in many Furutech fuses and it goes through several painful areas. There are days in Furutech rhodium burn-in where I would sit down to listen and the sound would just be so bright / harsh / hard-edged that I said “I can’t listen to this”. At that point, I would just walk away and let it continue to burn in. With the PADIS fuses, it never got that painful. I could hear the burn-in process changes, but it was always listenable. At the 180-200 hour mark, the PADIS did get very bright/hard-edged, but it was still somewhat listenable (I did not have to walk away). At 220 hours it was fully resolved.

Now, for the comparison. I will say that the PADIS is an excellent fuse. For the money, you really cannot beat it, unless you need a warm signature (in which case you need an Isoclean fuse). Both the PADIS and Furutech share the same essential sonic signature. However, there is definitely a difference. The PADIS sounds very good – do not get me wrong, it is an excellent fuse. However, the Furutech really did have an improvement. The tones on the Furutech were just a bit more pure and true sounding. The Furutech had a more “solid” sound to the audio. The Furutech had a bit more punch and meatiness to the bass / midbass. The PADIS, on the other hand, was a bit more loose in the highs, causing the high frequencies to be a bit more messy and rattling. This does cause the PADIS to sound a bit more dry. The PADIS also did not have quite the depth of soundstage when compared to the Furutech.

Now some people might sit down with me and say “I can’t hear a difference” or “your just splitting hairs”. I might be. The difference in sound is VERY subtle, but to me it makes a significant improvement. The differences could also be revealed when listening over a longer period (like 20-30 minutes). The music with the Furutech is just more engaging.

If you have very low resolution or warm equipment, it is possible that you would not hear the difference at all. However, on high resolution stuff, the Furutech could make that equipment “shine” just a little bit better. The PADIS is an excellent buy. For half the cost, you get a whole heck of a lot of performance (almost a no-brainer if you’re still running a stock fuse!). For those who want to bleed out the most amount of performance and resolution – the Furutech is worth the cost.

There are a few possible reasons I can think of that would cause the PADIS/Furutech difference:

- Furutech fuse state a special damping filler inside to reduce electrical resonance. I cannot find an reference to a damping filler for the PADIS fuses.  This could be why the PADIS sounds a bit more loose/dry/harsh in the highs

- Furutech does a Cryogenic treatment process. I cannot find any reference that the PADIS fuses get the same treatement.

- Rhodium plating. It is possible that the Furutech fuses are manufactured with a much thicker rhodium plating. I know Furutech likes a thick rhodium plating on their A/C connectors. The PADIS could have put a thin plating on their generic “PADIS” fuses. This could help explain why my burn-in process was not as painful.

Anyways, those are my findings. Maybe next year I’ll do a BLUE vs. Furutech analysis.

auxinput
Regarding the fuse breakin device shown at the link Nonoise provided, which I hadn’t previously seen, one of our other members recently asked me for advice as to the specific parameters that are involved in constructing such a device (which are not indicated in the video, and if not properly chosen COULD EASILY RESULT IN BLOWN FUSES). Here is the answer I provided, which apparently worked out well in his case:

I did some calculations of the resistance of various light bulbs based on their wattage ratings, which reflects their "steady state" resistance following the brief warmup that occurs at turn-on. I also measured their resistances with a good multimeter, which reflects the "cold" resistance they would very briefly have just after turn-on. The bottom line in each case was well over a 10:1 difference between those two resistances.

Which makes using a light bulb a tricky matter at best. Depending on the fuse rating and the wattage of the light bulb you would probably have either too little "steady state" current to be effective in a reasonable amount of time, or too much current during the instants following turn-on, which might blow the fuse.

I also thought about the possibility of using a resistor instead of a light bulb, since a suitably chosen resistor would provide essentially the same resistance immediately following turn-on as it would subsequently. However the problem with that approach, assuming you would be powering the setup with 120 volts AC, is that the power handling capability of the resistor would have to be very large.

So what I would suggest is that you use a Variac in conjunction with the light bulb approach. I suspect that you can find a used or possibly a new Variac inexpensively at eBay. That would allow you to bring up the AC voltage applied to the light bulb/fuse combination slowly, to avoid excessive current flow while the bulb is heating up.

The resistance of the fuse itself would be negligible compared to the resistance of the bulb. The resistance of the bulb can be calculated from its wattage rating (its actual wattage rating, not the "incandescent equivalent" rating) based on the following relation:

R (in ohms) = (120 volts squared) / (wattage rating)

So for example a 53 watt halogen bulb having a 75 watt incandescent equivalent rating would have a steady state resistance of:

R = (120 x 120)/53 = 272 ohms.

The resulting current would be:

I = E/R = 120/272 = 0.44 amps

For a bulb consuming 100 watts:

R = 144 ohms
I = 0.83 amps

For a 250 watt bulb:

R = 58 ohms
I = 2.1 amps

The burn-in current should be limited to no more than around 1/3 or at most 1/2 of the current rating of the fuse.

Variacs intended for 120 volt applications can generally be turned up to put out voltages that are somewhat higher than that, so you would probably want to use a multimeter to determine the setting corresponding to 120 volts.


... Regarding flicker bulbs, a point to keep in mind is that the only audio components whose AC power draw fluctuates significantly are power amplifiers that are not biased in class A. Or subwoofers or speakers which incorporate such amplifiers. Class A amplifiers, preamps, other line-level components, phono stages, etc., all draw essentially the same amount of AC current at all times.

Regards,
-- Al


@auxinput, I had to reread what I wrote several times before I realized what I did and then when I typed this, I did it again! I have to pull my mind out of the gutter now and again for perspective. 

@almarg , I had no idea that something that looked so simple and innocent could be so deleterious. Thanks for posting.

All the best,
Nonoise
I followed Al’s advice above when building my DIY Fuse cooker and it worked like a charm. Cooked two HiFi Tuning Supreme 2 amp coppers for four days with no issues and I have heard no further changes in the sound of the fuses after installation. .

The most significant thing IMO is that Al’s calculations demonstrate that the 3 amp flicker bulb used in that video does not pull enough current to do anything to exercise the fuse. The 100w incandescent bulb with the 2 amp fuses in series as suggested from Al’s calculations worked great for me.

Dave
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