Hi-Fi Tunig Fuses & Parasound A21

Fuses are not in any signal path except in the broadest sense that many of the electrons used by an amp can somehow become signal…sort of…One of the most telling aspects of the premium fuse charade promoted by, as an example, the athletic SR fuse salesmen in the main SR thread, is an utter lack of understanding of or desire for any sort of reasonable technical explanation of how or why these "special" (and relatively expensive) fuses work their magic. I asked once, and was told to call SR as why should these SR Super Fans do the "heavy lifting" for me?…they simply have no idea beyond referring to the Quantum Tunneling or high voltage exposure or other nonsense used in SR promotion baloney. I smell fraud all over this stuff, and any other inexplicable techno tweak like tiny aluminum "transducers" (some know what "transducer’ actually means), and have tested the efficacy of Special fuses and found them to be a silly waste of money. The astonishing imagined benefits of pricey fuses is simply one of those head scratchers to people who are in the amp design business, and any of them I’ve asked about this stuff simply say something like hey, fooling people into thinking what they paid through the nose for is worth it if enough others claim it to be so is all some people need.

From the silent majority, we have a 180 (or is it 360?) degree view on the subject of fuse directionality.

atmosphere = +100

geoffkait = -100

Atmasphere is certainly not alone in his contention, which btw he has indicated in past threads he has confirmed via measurements. See my post dated 10-28-2016 on page 58 of the long-running thread https://forum.audiogon.com/discussions/synergistic-red-fuse?page=58, in which I cite relevant comments not only by Atmasphere but by three other highly experienced designers of well-regarded audio electronics.

I also state in that post, as a highly experienced electronics designer myself (in the defense electronics field), that "claims of directionality in fuses [are] fundamentally irreconcilable with any reasonable understanding of how electronic circuits work." While also completely recognizing, of course, "that an understanding of how electronic circuits work can’t explain or predict everything about what we hear or don’t hear from our systems."

Finally, even if contentions that fuses inherently have audibly significant directional characteristics are correct (which they are not), it would stand to reason that the effects of any such directional differences would be completely swamped by the much greater directional differences that would presumably be caused by the vastly greater lengths of the associated wiring. In the case of AC mains fuses that would include the wiring in the primary of the power transformer, the internal AC wiring of the component, the wiring in the power cord, and presumably even the AC wiring inside and outside of the house.

Geoff (and others, most of whom are also not electronics designers) will of course disagree with all of this, but that’s how I (and the four well-regarded designers quoted in the post I referenced) all see it.

Regards,
-- Al

atmasphere
5,020 posts
11-16-2016 10:59am
I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse. This is not caused by reversal of the fuse but how it makes a connection. Quite often by reversing the fuse you get a better connection because the fuse sits better in its holder and thus there is a lower voltage drop across it.

IOW its the connection, not that its reversed. If the only way to get the fuse in the holder is by removing the fuse cap, you might not have much option but to reverse the fuse to see if the contact is better."

Sorry, Charlie, nice try. But that’s simply not true. When the fuse itself, without the fuse holder even involved, there is a bigger voltage drop for one direction over the other. Hel-loo! Besides, careful and thorough testing reveals that the direction of the FUSE is actually more obvious in listening tests than any directionality the contacts of the fuse holder may or may not produce. More importantly, the direction of all wire, not only the wire on fuses, is directional. You can say that it’s the contact until you’re blue in the face, it’s no skin off my nose. This is an excellent example of the Backfire Effect, the more someone’s belief is challenged the more he believes he must actually be right. Common in this hobby, I might add.

I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse.

This is not caused by reversal of the fuse but how it makes a connection. Quite often by reversing the fuse you get a better connection because the fuse sits better in its holder and thus there is a lower voltage drop across it.

IOW its the connection, not that its reversed. If the only way to get the fuse in the holder is by removing the fuse cap, you might not have much option but to reverse the fuse to see if the contact is better.

6.3A fuse ?

Thank you. I have just bought one Hifi Silverstar for the main fuse. Will try it and let you all know the result.

FYI  The Parts Connexion has a sale on HifiTuning Fuses going on now.  I am awaiting the arrival of four silver star fuses.  They were 60% off!!

Hello,
I am thinking of replacing the stock fuses of Parasound Halo A21 and have a couple of questions for this audience who have hands on experience with fuse replacement.
1. It seems to me that the main fuse which is in the signal path would be the most important fuse to replace and would yield the max improvement in sound. Replacement of the 4 internal fuses in the rails not being in the signal path might be optional. Would you agree?
2. My fuse options are Hifi tuning Supreme and Synergistic Quantum Black. I read rave reviews of Hifi tuning fuses used in Halo A21 but not so much on the new Synergistic Black fuse. Did anyone have an opportunity to compare these two fuses?
3. I tried cleaning the main stock fuse with DeOxit Gold contact cleaner and the result was a very harsh sound as if the fuse was not broken in. I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse. Did anybody experience this behavior with the direction of the fuse be it a stock or an expensive audiophile fuse?
Thanks

Given this option for the A21 is it the same on the A51's?

Thanks again guys. I would start with the AC Main fuse first then.

Milpai,

Glad to see you are thinking about this upgrade. Agree with the above description of benefits in general. I realize these are a fairly spendy add-on, especially if you are replacing multiple fuses. But for the benefit I think they provide in terms of improved sound, I am surprised at least some high end manufacturers do not specify them as OEM.

I agree with Rodman 99999, also Maggies are known for the ribbon tweeter with outstanding high`s, the fuses gave an obvious improvement with even more resolution way way up in frequency, that was a pleasent supprise.
Len W

The best way I can describe the difference is, "more organic". ie: Vocals sounded more as though they were coming from an actual body(chest resonance), upright bass had a woodier body resonance, I could hear more skin and stick on drums, could sense more of the rosin in the sound of bowed instruments. One probably wouldn't miss these things, if they never listened to live music(or, at least, not often or closely enough).

Thanks Len and Rodman99999.
Roadman99999, I like your idea of first replacing the AC Main fuse first.
BTW, what differences did the fuses make in your systems?

Replace the AC Main fuse first, and if you appreciate the differences that makes(a VERY likely probability); replace the rail fuses as well. Happy listening! BTW- NONE of my HI-FI Tuning fuses are coming out either.

Not Parasound but I have replaced every fuse in my ARC PH7, Ref 3 and ARC Classic (tube) monoblocks with HI-FI tuning fuses. None are ever comming out!
I did not put them in all at once. I did them one at a time and moved on to the next. They even worked great on the Maggie speakers. I know what I hear and none are comming out!

Len W