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In Reply to: RE: Fuse direction? posted by mojul on January 14, 2023 at 08:15:39
The fuse is operating in an AC circuit. The amplifier has two power transformers. The line fuse is between (in series with) the incoming AC hot side and one lead of the primary of each of the power transformer. Current will reverse direction twice each cycle. (120 times per second if the AC is 60Hz)If the fuse was operating in a DC circuit then there might be a possibility that it could be directional.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 01/15/23Follow Ups:
Hi Tre
I believe your picture shows the inside of the Gamut D200?
I very much love the sound of this single MOSFET amp, had a Sirius DMX 100 before, that also was a single MOSFET. The Sirius company changed name to GamuT and I think their sound is in family, although the D200 is in a another league ;-)
mojul
"If the fuse was operating in a DC circuit then there might be a possibility that it could be directional."
Have you personally experienced DC circuit fuses that perform noticeably different when direction gets reversed?
What are the characteristics of the performance differences?
I'm assuming you're talking about "normal" fuses intended to prevent overcurrents with carefully engineered melting metal elements...
"Have you personally experienced DC circuit fuses that perform noticeably different when direction gets reversed?"
No.
To me this is all very silly without a base line. The only way to tell if some fuses are better than others (and I think that is where we should start before we get into directionality) is to run a unit without a fuse and see what that sounds like (and tests like) and then see if we can even hear a difference when you put a fuse in for safety. If we can't hear that then the whole "directional fuse" question is moot.
How much of a voltage drop do you think happens across a fuse?
There are things that might make a theoretical difference but that does not automatically make them audible.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
OK. I see. Good points.I'm skeptical the evidence from such experiments would support altering the original design in most cases but....
If the voltage drop, presumably caused by the fuse current modulating the element impedance, in audio equipment protection fuses, is noticably finding it's way into the audio signal in some pieces of gear.....and users truly have taken modifying some aspect of the safety design to overcome the damage it does to the products performance, maybe it would be best for everybody if that piece of gear would get removed from the market before someone gets hurt.
Edit: BTW definitely not holding my breath waiting for that piece of gear to surface as it would immediately be laughed off the market and out of existence and I am under the assumption that unqualified individuals, prone to monkeying with their safety circuits, being a bit stunned seems more likely.
Edits: 01/16/23 01/16/23 01/16/23 01/16/23
"is to run a unit without a fuse and see what that sounds like (and tests like) and then see if we can even hear a difference when you put a fuse in"
There are people claiming certain fuses sound BETTER than bypassing the fuse! Until I try it myself, I will not rule in or rule out the possibility, but it does nauseate me a little bit that fuses exist that cost near $3000...
That's LAST years price.
If they've gone up in price 10% (like a cup of coffee has) since then, well...
"Once this was all Black Plasma and Imagination" -Michael McClure
... getting started. I believe their top-o-the-line Gold level comes in at $10K. I believe it has just launched.
Thanks. I gotta see this to believe it.
QSA audio
Errr, a fuse using AC has no direction due to the voltage passes each way (forward and backward) thru the fuse. Anything you hear is placebo effect.
Yes, as has been covered 1000 times before. I have no subjective experience in this arena...I'm just reporting on what's currently available in the marketplace.
Below is a link to a post by Ralph of Atma-Sphere, regarding fuse direction, where he says perceived differences in sound are due to voltage drop. The less drop, the better the sound, according to him.
At the time, I misinterpreted his post to mean that the internal element of fuse itself was causing the voltage variation. When asking him about it when the subject came up again elsewhere, he explained that it was due to the amount of contact between the fuse and its holder. Apparently one direction often gives better contact than the other, and said, "Boutique fuses are a little better at this in general".
Note that I've never tried his suggestion, but the explanation always made more sense to me than those who believe in better alignment of the electrons from a $100 fuse, or some such thing.
Ralph is generally pretty good with his comments, but that one was nonsensical.
Of course there is a minute drop in voltage across a fuse. But that voltage drop will not increase (or decrease) if the fuse is switched in orientation.....all other things being equal. You could measure voltage across a fuse, switch its direction and measure again. Do that 100 times and compare the results and there'd be no consistency at all regards direction.
This requires no subjective evaluation, no voltage measurements, no anything. It's implicitly obvious based on the conditions the fuse is operating in.What we have here is schlock marketeers creating a belief in the audiophile brain and then selling a product to that belief. :)
Dave.
Edits: 01/16/23
Is that a lot also depends on in what the fuse is being used.
In the case I measured, the amp was a zero feedback tube amp with a rather large filament circuit (about 19 Amps). Because there's no correction, yes, changes in line voltage most definitely affect it (not only does the plate voltage go down but the tubes cool off a little as well)! To measure the effect on such an amp, measure output power, distortion and output impedance. With greater voltage drop, the output power decreases and the other two metrics increase.
WRT fuse direction, that is so much poppycock. What is happening is the fuse isn't perfectly symmetrical and can get a better connection in the fuse holder one way or the other, so less voltage drop. For this reason people wind up thinking they are directional, which obviously is impossible.
You can get the same effect by rotating the fuse in its holder without reversing it; measure for the least voltage drop.
We make a class D amp that employs quite a lot of feedback and as a result of the rejection offered by that feedback, does not seem to respond to fuses at all.
The takeaway is the current draw, the kind of load and what feedback is present all play a role.
There's nothing I'm not getting Ralph. I well understand there are different applications where fuse voltage drop might have a significant, maybe even audible, effect.What this thread is about, and what my comments have been about, is only in regards to fuse 'directionality'.
Cheers,
Dave.
Edits: 01/20/23
-
I suppose Ralph's sensibilities are why I've hung onto his voltage drop explanation as at least some form of an explanation for my otherwise skeptic nature.
One other thing which hasn't been touched on in this thread, and the primary reason I haven't tried a boutique fuse for myself, is that I don't know if I can trust their ratings. I'm not willing to sacrifice an expensive amplifier because the 4 amp boutique fuse I'd spend $150 on, actually wouldn't open until current reached 8 amps.
I think if that's the reason you're not trying boutique fuses you're missing the whole point.
Dave.
I don't think that I'm missing the point. I'm a born skeptic, but I don't consider myself such a pedantic theorist that I wouldn't at least try a boutique fuse if I had one, to prove to myself that these guys are imagining things.
Note that the key word is "try" though. I have no desire to actually buy a non-UL rated, non-returnable, disposable item like a fuse. But if someone handed me one, I wouldn't not try it.
This is not pedantic theory we're talking about here.If you hold open the possibility of trying fuse orientation to prove to yourself something then......? (This is the point I'm referring to.)
Some things are factually obvious without experimentation to prove it. If I have a wheel of known circumference and desire to know how many revolutions it takes to travel 100 yards, I don't need the wheel and a football field to determine that.
Dave.
Edits: 01/18/23
a Buss, Fusetron, or Littlefuse has an element inside it one half inches long ...that's for what used to be the standard size. I have cracked open a few over many years to see what the construction is and there is nothing in there to indicate that that small piece of wire soldered into both inside ends of the caps has anything to do with making a better sound if reversed. Only the addition of ingesting alcohol or drugs does that, or listening in the early morning and then listening in the evening after tweaking something like a 'normal fuse'. Just pulling a fuse out, cleaning the ends, and applying some Silclear or Deoxit will make a small difference.
And what about the specialty boutique types? Maybe, but I feel sorry for those who live for stuff like this instead of focusing on the god dam music.
Yeah, I think I'm pretty much with you, man.
Just asking to try and be sure someone doesn't know of something I've never thought about.
You never know around here. maybe.
I kind of half expected something like for example fuses temp coefficient of resistance cropping up as a real time system performance variable needing managing in some products.
Not that I expect that's a common problem for reasonably designed circuits.....
I am with TRE, fuse direction makes no difference same as cow dong makes no difference placed on speaker wires.
"cow dong makes no difference placed on speaker wires."
Not sure how putting cow dong on my speaker wires wouldn't change everything.
Cost is atmospheric.
.
Have Fun and Enjoy the Music
"Still Working the Problem"
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