2. tech-talk
  3. 130448-107

Fuses fuses fuses

Ok, this is about fuses

1- a standard Bussman fuse is UL approved. Are any "high end" fuses UL approved?

2- do any component manufacturers supply their gear with any of the usual suspects of high end fuses as opposed to a standard Bussman?

3- let's say fuses do make a difference. Given incoming power is AC, why could fuses be directional? 

Not meaning to light any fires here- 

thanks in advance 
128x128zavato
geoffkait's avatar
geoffkait
23,365 posts
 

georgehifi
Of course engineers have measured fuses.

Not in the way you promote them, they wouldn’t be stupid enough.

Cheers George

>>>>>If you’re pretending to be dense you’re doing an excellent job. ( Juror #2 from 12 Angry Men)

Who do you think measured the directionality of fuses that are shown in the HiFi Tuning data sheets? Engineers. And they measured fuses in EXACTLY the way I promote them. I.e., conductivity is better in one direction than the other. Duh! 
geoffkait's avatar
geoffkait
23,365 posts
 
Time for a fuse measurements recap. Interpretation of measurements. All aboard!

INTERPRETATION OF MEASUREMENTS (HiFi Tuning data sheets)

(verbatim)

There is a measurable difference in directivity of fuses. Mostly that will be due to the way the melting wire is manufactured. The difference is in the range of 5 % . That is in the range of variations due to the factoring process, but the difference is measurable with all types of fuses.

The resistance of the fuse itself is dependent on the length and thickness of the melting wire. At pure DC- resistance measurements, of the commercial available fuses, the solder type with leads gives the best results. Worst results gives the fuse with a glass tube and spiral shaped melting wire.

The high end fuses all give better results in conductivity, the cryogenically treated fuses from HiFi-Tuning give the best results, while the rhodium coated fuse from Padis gives the highest DC- resistance.

For DC applications it ́s recommended to use the solder type fuse or the cryogenically treated fuses from HiFi-Tuning Germany.

The drop in resistance up to the factor of 8 is clearly measurable and also could be detected in listening test.

Fuses with a glass tube and a spiral shaped melting wire are additionally by a factor of 20 more sensitive to micro phonic effects. Fuses with a glass tube and a straight wire still by a factor of 5.



bdp24's avatar
bdp24
9,865 posts
 

Modjeski tested the resistance of the Hi-Fi tuning fuses in both directions, and found a difference of 0.038 milliohms. I don't know about 5%, but 0.038 milliohms is an EXTREMELY small difference. I have no doubt that fuse directionality proponents will say the difference in sound is due to other factors. Like what? Oh yeah, wire directionality ;-).

Roger called and talked to both the Hi-Fi Tuning fuse U.S. distributor, and the fuses German designer. Neither knew what the term "high breaking capacity" means. Roger strongly advises against putting a Hi-Fi Tuning Fuse in a DC circuit (tubes run on DC), as a fuse lacking hbc will not protect an amp---by blowing, when a tube goes bad---as they all eventually do. Even a new tube with a short will blow a fuse capable of performing that function, which the HFTF in a DC circuit is not.

Roger Modjeski characterized  the Hi-Fi Tuning Fuse as "junk". But then he's delusional ;-).

almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
Geoffkait 7-16-2017 (quoting the HiFi Tuning paper)
There is a measurable difference in directivity of fuses. Mostly that will be due to the way the melting wire is manufactured. The difference is in the range of 5 % . That is in the range of variations due to the factoring process, but the difference is measurable with all types of fuses.
From the threads I linked to in my post above dated 7-13-2017:
Almarg
In fact, all or nearly all of the directional differences in resistance were vastly smaller than 5%, with the exception of the "standard glass fuse." However, even in that case, if per my comment and Roger's comments the OVERALL resistance for both directions is insignificant, the DIFFERENCE in resistance between the two orientations will certainly be insignificant.
Roger Modjeski
From the Tuning Fuse data sheet their 2 amp slow blow 5x20 fuse has a resistance of 24.077 milliohms in one direction and 24.115 in the other direction and 26.257 in the holder. If a butterfly flew by while the measurements were taking place we might see a bigger difference than the 0.038 milliohm difference in direction. Of course it might depend on which direction the butterfly was flying. But never mind, the direction measurements were made with DC and we are using these fuses in AC circuits. Perhaps if the butterfly flies clockwise vs counterclockwise there will be a difference.

Sorry I just had to put that in to keep up with all the humor that has been presented here.

[Note: 0.038 milliohms is 0.000038 ohms]

Almarg
Regarding the measurements described in the HFT paper ... which purport to support the notion of fuse directionality:

IMO those numbers are so miniscule as to be:

(a)Laughable.

(b)Very possibly attributable to changes in the voltage of the battery in the measurement meter, from measurement to measurement (each measurement imposing a slight drain on the battery), and from minute to minute. Or if the meter was AC powered, to the very slight differences in AC line voltage that may occur from minute to minute, as various loads are turned on and off at nearby locations.

(c)Very possibly attributable to differences in contact pressure and contact area between the meter’s probe tips and the contacts on the fuse. The paper presents separate measurements of fuse resistance as measured in a fuseholder (for just one direction), indicating that the direction-related measurements were performed by touching the meter leads directly to the contacts on the fuse.

(d)Perhaps even contributed to by differences in the resistance of the measurer’s body, that would have been paralleled with the resistance of the fuse if he or she had fingers on the probe tips and/or the fuse contacts while the measurements were being taken.

(e)If Geoff’s comments about all wires being significantly directional are to be believed, then these differences would be totally swamped by both the resistances and the alleged direction-related resistance differences of the vastly longer associated wiring. In the case of mains fuses, that would include the power transformer and the power wiring in the component, as well as the power cord and the AC wiring in and outside of the house....

.... Yet despite all that, and despite similar comments about the HiFi Tuning measurements that have been provided in numerous other posts going all the way back to the "Fuses that Matter" thread that began in 2012, Geoff continues to assert that the HiFi Tuning measurements support the notion that fuses are inherently directional.

Regards,
-- Al
 

geoffkait's avatar
geoffkait
23,365 posts
 
bdp24 - Well, if I can be so bold at least we now know Roger Modjeski must be deaf if he can’t hear the difference in fuses. He’s deaf and stubborn. Amp manufacturers! Harumph! Uh, Mr. Smarty Pants - Why should there be ANY difference whatsoever in measured resistance if fuses are not directional? They should measure exactly equal. He’ll-loo! None of you Barko Lounger experts have figured that one out, eh? Besides, HiFi Tuning acknowledges the differences in measured resistance don't compor entirely with the sonic differences. It's a Strawman argument on your part to put words in anyone's mouth that anyone thinks there must be some other, as yet unexplained, reason for the sometimes great difference in the sound between fuses and between directions. 
More to discover